Surplus electronic parts :
Stock and Crypto AI Prediction :

Today's live stream continues exploring the installation mindset. Duct experts Neil Comparetto and Michael Housh join Bryan to discuss ductwork, venting, and commissioning as they relate to the HVAC installation process.
Many problems that occur during installations stem from poor duct design. Ductwork requires a lot more thought and planning than just using ACCA Manual D. Duct sizing is important, and HVAC systems often lose efficiency to takeoffs and return drops that are too small; Michael and Neil like to make the ductwork as large as possible to improve the equipment operation and use large filters effectively. Some equipment coils also have more pressure drops than others, and the ductwork needs to be able to deal with that. Know the performance of your fittings and what their equivalent lengths are.
When you use filters, you want to make sure you maximize your surface area for the best filtration. The pleats of filters increase the surface area and effectiveness of each individual filter. Creating plenty of filter grilles and returns for your filters allows you to increase filtration without creating too large of a pressure drop. (Remember to use filters with high-quality media, and don't be afraid to diversify your filter selection if the ductwork has unique needs!)
Oversized units may present issues with the ductwork. Whenever possible, look for opportunities to downsize the HVAC equipment during a changeout or retrofit.
Turning vanes can confuse some technicians. These are usually more beneficial in supplies than returns, and they shouldn't present an issue if the ductwork is large enough in the first place. When installed correctly, these turning vanes can help even out turbulence and are great in cases where you have space constraints. When configuring elbows without turning vanes in the ductwork, make sure that the throat (inside) is large enough and that you have enough space for them.
When it comes to metal duct fabrication, you need to think about getting the ductwork off the shelf as quickly as possible. Retrofits can be tricky and may require some custom adjustments to the ductwork. Modifying fittings can take more time than creating your own transitions. You'll also want to pay attention to the size of your air handler; larger air handlers can leave you without enough room to make a good supply transition.
You'll also want to think about the ductwork's relationship to the structure. Neil recommends decoupling the ductwork from the structure as much as possible, such as through canvases. Cross-breaking is not as important as one might think, but you can still do it if you think the sheet metal might not be rigid enough.
Flex duct provides a unique set of benefits and challenges. Flex ducts reduce noise, are well-insulated, and are leak-free. However, they can lead to poorer airflow if installed incorrectly. Keep flex ducts straight and tight, and you'll have no problem.
When burying ductwork is a bad idea, strapping and routing are the processes that support the ductwork. Codes will give you a guide when it comes to the spacing between supports. Wider straps provide more support, especially if you can use a "saddle" material underneath.
Leak prevention is critical in sheet metal duct systems. The best approach to solving duct leakage issues is methodical, not reactionary. You'll get the best results by approaching a job with the mindset of minimizing leaks from the beginning; use mastic on your elbows and do as much prep work ahead of time as possible.
You only need to worry about venting when you use gas appliances, not heat pumps. Venting can go wrong when people size the flue incorrectly or use the wrong pitch on condensing appliances. However, most issues can be avoided by simply reading the manufacturer's literature. Pay attention to your terminations; avoid areas where terminations can be covered by snow. You should also check for signs of backdrafting, which is a dangerous condition.
Commissioning is the time to set airflow correctly. The more measuring and benchmarking you do, the more likely you will catch something that could cause problems later. Static mapping is a great commissioning practice. Of course, you'll also want to check the refrigerant charges or combustion analysis before walking away from a newly installed system. Even though we highly recommend reading manuals and using all your resources during commissioning, your best tool will be good old common sense.
We also discuss:
Duct design modeling software
Balancing dampers and design strategies
Strategies for sealing fittings
Drilling register grilles into place
Addressing leak points at the boot
Using a Ductulator or duct slider
Using rules of thumb
Gas piping
Orphaned water heaters
Using manuals
Check out information on the 2022 HVACR Training Symposium at
Read all the tech tips, take the quizzes, and find our handy calculators at

Start with i want to uh introduce our guests today. We've got a crackerjack team here with us to discuss, commissioning and installation. I think that's the technical word um, so we've got neil compareto from compareto comfort, solutions in virginia and then michael housh from housh. What's that? What's the what's the whole name of the company, the home energy experts house, the home energy experts? That's right! I knew it was something snappy like that um in ohio, and so i want to start with you.

Uh michael um just give us a quick introduction, because there's a lot of folks who haven't uh haven't met you before um, just what you do and how you got into the trade um, i'm a third year or third generation owner a little more than third year. Yeah our company started in 1954 by my grandfather, um, i'm kind of known for duck designs, my 3d drawings that i do um and i've kind of worked in most every aspect of the trade at some point. So that's brief description of me yeah. What i like about michael, is not only um.

Do you have a lot of uh experience on the design side, but also as a technician doing it doing installations and then also on the building science side? So as it pertains to the topics we're going to talk about today, i would definitely consider michael to be uh one of the foremost experts uh. Next we have neil compareto who we have to always introduce by saying neil compareto inventor of the comparator, cube um. Do you have you ever introduced yourself that way like either tongue-in-cheek or or you know, on the nose? Is that ever no? No, that's just me. Okay, you've introduced me a couple times a few few times.

Yeah yeah i mean when you invent something as prestigious as that featured on this old house. You know yeah you're a big deal. You really are you really are so um yeah. So tell us a little bit about you, neil.

Well, i'm a residential uh, hvac home performance contractor a third year contractor um started a business three years ago. I've been doing hvac since uh since 2000, so a little over 20 years mainly focused on installs. The the whole time and kind of you know started out. Just as a job and as i got more responsibilities, i kind of learned to love it and uh really dug in you know, probably about seven years ago and kind of progressed since then.

Um so yeah we're a small company. We're focused on high performance, hvac uh, trying to you know, do the high quality jobs trying to fit small units in big spaces, and we kind of do it from start to finish. Where we design build, commission and uh see the whole project through, and we do a little bit of not a little some home performance where we're doing you know attic insulation, encapsulations, crawl, spaces, uh things like that, so we're kind of focused on a holistic approach to Comfort um in residential houses, wow - that was a it, was quite an elevator introduction there very nice and and very true, very true, all very true, um yeah neil's, very thoughtful um installer. He always, you know, thinks through the details very well, which always makes it for a great discussion when we're talking about specifics of installation practices um, which is what we're doing today so um to start with.

I want to. I want to give both of you um. Just a few minutes to kind of riff on if you're going to, let's say somebody comes to you and um, they are having issues with their duck design, so we're going to start on the design side. I know this is an installation class, but but a lot of problems that happen in installation actually stem from poor designs.

So because i probably among the questions that i get most often they're about, you know, failures and design. How do i design duct systems better? So obviously, we've got the you know kind of the trite answer which would be well. You know use zach manual d, that's what that's what everybody says um, but where would you start for somebody who honestly wants to do a better job than they've been doing? Because i know especially for you, neil, i know, you've walked down that path of, as you got into different designs, having some struggles. So where would you where? Would you point people first i'll actually start with michael here uh i mean, i think, one of the keys and i in my market, it's actually kind of difficult to do.

Duct upgrades a lot of the time and so um. I focus a lot on near equipment. Changes and basically make everything as big as you can um, and so sometimes uh even uh. If you're just trying to uh make an existing duct system more efficient, it can be um like increasing the size of the takeoff is a big winner, a lot of times.

Um and then what we call the big air drop by, basically creating a very large return. Air drop um, roughly the size of whatever your filter opening is so we use a lot of 20 by 25 media filters, and so we have a giant 20 by 25. Return drop coming down um, so those tend to be the most helpful. Obviously, there can be some choices in equipment, selection and stuff too.

That can help. I mean some coils are just have a huge pressure drop um. That may be, you know above the pay grade of someone who's going out and installing something they may not have that choice or whatever, so they kind of have to deal with what they've got but um. So i'd say those are some of the main things for me is basically just trying to make everything as big as i possibly can yeah, especially close to the equipment.

That's something that you talk about a lot and i think, is a really um. It's a good thing that even an installer can focus on a lot of times as an installer. You have enough autonomy that you can make some choices about. What's right, next to the equipment, when you're doing a change out changeout and you may be able to say, hey look, we could we could fit a little larger media filter in here and we can make this return a little larger.

We can make the supply duct that attaches to the to the unit a little larger, and you can greatly improve the equipment um operation doing that because, obviously, the ductwork that's closest to the equipment. Um is going to be what affects the equipment operation uh the most now. Obviously, that's not the whole story. The whole rest of the duct system also matters obviously um, but the equipment or the ducts inducting next to the equipment and up sizing that, i think, that's great advice.

What are some of your top um things? To start with, neil, i mean you made a good point: you and mike um that you know at the equipment's, where pressures are the highest right, so um getting that right is really important. Um. If you get that wrong and you get the rest right, it's probably not going to work, um so low hanging, fruit or filters, making them really big as big as possible. Maybe even two.

If you're, you know filtering close to the equipment we like filter grills. So we can kind of dictate the size better, so sometimes you're limited in the mechanical room for space, but you can get a big filter, grill somewhere else, uh on the supply side. There's things like that. You know when i was in dc.

We did in a lot of retrofits um and where i would have uh like turning vein blanks. I don't know what you would call it, but basically, i you know measure a job up. I see some opportunities close to the equipment where maybe we're not gon na replace the duct, but we can insert our turning vein into a few of these branches off the plenum and it's just it uh. It really helps as far as you know, kind of mentioned.

Uh in introducing this question on manual d, but it really like if you're starting from scratch, it's just you know you have to go through the process. It's and it's not like a difficult process. It's kind of people i think, are intimidated by it, but um you need to find out what the heat loss and gains of your space are. You need to select the right piece of equipment and then you need to uh, do a duct design and it's as far as manual d, it's literally it's a spreadsheet and it's not that complicated and once you get, you know a little bit experience doing that you Can start, i want to say rule of thumbs, but you can start to speed up your process by not by identifying certain areas and knowing that you know if you, if you have 140, cfm or 150, that you know an eight inch round's gon na gon na.

Do it and you have some cushion there to uh, you know, make a turn or two with it and so yeah you know, and then you can always make the duck. You know make the ducks big. You can always dampen them down, not a big deal uh. Having ducks too big as long as they fit, so i think with that uh on that manual d topic like even if you don't use manual d or maybe a good starting point - is to find just the duct fittings and the equivalent length that they equal.

So that's like a certain section and um. I share it oftentimes i have it broken out where you can just kind of look through all the fittings and see like um and also going back to the near equipment stuff so like on a supply plenum. A lot of times around us they'll have just a straight take off square takeoff for the supply trunk coming off, where replacing that with uh like a riser take off, is you know, half the equivalent length of that one fitting kind of deal, and so a comp Like getting comfortable with even just what fittings are better performing fittings and so basically the lower the equivalent length, the better okay and so right, if you have a room to do a straight boot with the elbow, that's like 20 feet and 90 boots 80 feet. So yeah, if you have room to do certain things you can start.

You know it's almost become second nature, where you know i'm not going to do that because uh, i can do this and it's you know four times as good yeah again the the idea is that we're trying to reduce turbulence in our duct system and uh in Doing so, we uh reduce our resistance, reduce our friction um to the airflow and so that results in a better performing piece of equipment. That's the goal, and i i wanted you to talk a little bit more neil about the filtration question. You talked about that um a little bit in terms of using multiple filter grills. If you can, but i think some people they don't, they don't necessarily get it because they just think.

Well, you know what what's wrong with what's wrong, with just putting it the filter in the unit that is designed to come with the unit right, i mean that's it's designed for it. So to what advantage is there in putting these multiple large? You know two inch thick filters. Why does that make sense? Yeah i mean it's. It all comes down to uh.

You should want good filtration. I hear it all the time about. You know these see-through filters on how they're great and they're they do fine. And what else do we hear that the filters for the equipment not for people? No, i mean you're filtering air, there's tons of data out there, showing that when you run good filters, uh particles in your house are are way lower.

So you want to have good filtration, and in order to do that, you need more surface area. The equipment is really designed. The footprint of the equipment is designed for a merv 2 filter. You start putting the home depot.

You know 3m filters in there and we've all. You know, there's text on here: we've all seen it. It doesn't work even a lot of times. You know four inch filters.

Uh are questionable uh. If they're the footprint of the uh, the equipment, um heat pumps, we can get away with it a little more because we have a little bit more of a budget. Uh airflow budget, but um you know the goal should really be to um, make your filter as big as possible, and you know ways of doing that are you know. Michael does a great job with the uh, the big air drop um, where he puts the filter.

Um horizontally next to the piece of equipment that way you're, you know: you're you're, not limited uh as much on size. We like to filter at the filter, grills our return ducts. We basically test if we're doing a new system, we're testing duct leakage. So we know that if we put a filter at the return grill, we have tight ducts.

We put gaskets behind the filter or we tape them in that that equipment is going to be clean like forever. Basically, as long as the homeowners keep up with replacing the filters again, we like gaskets, because it's a little homeowner friendly, where you know it - does a really good job of minimizing uh bypass but yeah the gist is um. How are we going to get the filter as big as possible, so a five inch filter has pleats like this. You stretch it out.

It's you know ten feet and a one inch filter goes like this. So um you can either do it with uh media cabinets at the equipment or, if you have multiple filter, grills um. That's another great opportunity to to increase your filter without filtering without uh, sacrificing a big pressure drop, yeah maximum actual face area that we can get with maximum media surface area um and with good quality media, so higher merv rating. We can potentially get everything we want.

So low face velocity, meaning the air is moving slowly across the filter media, that's good, because the filter media can catch more right. We can also reduce our pressure drop because we've got more surface area for that air to move through at a lower velocity. So that's good because it's not affecting the equipment and so all in in many cases you can even make choices in terms of the filters that you choose so they're not terribly expensive as well, which is another thing i know you you know are also thinking about. Quite a bit uh.

This is the way that we, i got a lot of neil's advice for building my dad's house and we did an ultra low um pressure drop design on the air filter. We did the gasketed double filter back return and the entire system total external static it was an infinity system, was under 0.2 for everything and the system just performs really really well all metal dock system in florida believe it or not, and it just performs really really Well, so uh it can be done. I guess is the is the point there if you design for it now we don't always design for it and when we're doing changeouts, sometimes that can be challenging. We have to work with uh work with what we've got um.

Let's talk a little go ahead. Let me sorry, let me just add sorry add one more thing is um, especially in the changeouts, where a lot of times, where limited on what we can do, budget wise and sometimes uh. You know the equipment's too big. So when you, if you're able to downsize equipment, it magically makes a lot of things better.

The duct system, the filters, everything and there's there's a lot of opportunity out. There. We've done several houses recently taking a four ton unit and taking it to a two ton. Leaving energy monitors an ieq monitor, so we can see that it's maintaining temperature um but yeah.

So you know part of part of the duct. Design too is: is the equipment um in a retrofit yeah looking for opportunities to downsize the equipment is huge. I i i wonder if you want to talk for a minute about that, michael both the filtration side and then also um, you know finding opportunities to downsize equipment yeah for sure all of those are good things. What's popping into my mind during this conversation is a lot of these things have to come from the top down, which also may be difficult right like so either the sales person has to sell these items or your business has to yeah.

You know be on board with it right, so it can be kind of hard when you're the one just going to install the piece of equipment but um you know, like neil said. I think that downsizing a lot of times makes things magically better oftentimes. That's the biggest opportunity we have in my area, because ducks aren't always replaceable, like i mentioned in the beginning, and so by doing some near equipment things and um. Also, like you know, we used to always just do the same size filter for like every system.

You know what i mean and, and it was always like one inch, filter, racks and um. You know now we adopted a strategy of during our quoting process. We include a media filter and the price for the big air drop and make people decline it as opposed to um the other way around and 90 of people just kind of accept it, especially once we go through our conversation and stuff, but otherwise it's kind of Their problem, if they want to go with worse filtration and all these other things that make a system just kind of work, a lot better and keep it clean, and you know there's all these positive benefits, and so it seems to be something that makes uh or Is a lot easier when it's adopted as a whole from the company, i guess would be my intake or input there. What about the question of turning veins? It seems to come up a lot um.

I guess i guess this all has to do. Of course, with total uh effective length and uh equivalent length and then also um, you know the idea of turbulence, but a lot of people. You know they want to. They want to see.

You know rounded transitions on the outside um of a duck, but they don't think about the throat. Am i saying that right, there's throats on the inside right and then heels on the outside? Is that right, throw it in heel? That's right! Okay, yeah! I always get those ones mixed up. I don't know why, but i just do so. Uh talk about those kind of three things.

Um are those things that an installer should be thinking about. In order to uh, you know, keep air moving a little bit more laminar. A little bit more straight, i think, there's definitely setups that require it more than others. You know part of it.

Uh is less problematic. If you go with the theory of keeping everything as big as possible um, it also depends on what side of the system you're on turning veins are probably more beneficial in supplies versus returns. However, probably some areas like or systems like in florida in your area, where you have uh, maybe a a real, sharp turn into the bottom of the air handler um. You can get some weird turbulence and stuff there that turning veins could potentially help.

Uh have a more even flow across the coil and not uh be problematic. So it's really a and it depends thing and for me we'll use them if we're not able to make the duct size as large. As i want it kind of thing. If we have space constraints - and you can also have problems if turning veins are field installed and they're installed wrong, they can create worse problems, and so you have to know what you're doing um and so for for us.

It's kind of something that we let our sheet metal shop do or all like. I like to tinker with things, so i may make some and do them myself, but i'm not super confident in other people doing unnecessarily yeah anytime there's an opportunity to do something wrong and make it significantly worse. Um, i i prefer not to add it to the mix unless i need to so. I think turning veins um in residential applications can fall into that category.

If you're, not, if you're, not careful any thoughts on that neil yeah, i mean i definitely if you do them, you need to uh check that they're lined up right. I pretty much adjust. Probably 50 percent of them, see we we sub out our duck fabrication. So um, you know when i get them, i uh adjust them um a lot of times.

Michael made a great point where you know when you lower the velocity in a duct system, you can get away with a lot of things that are uh wrong um. So you know in the return close the equipment - it's usually easy to do that. So that was something that i had to uh to learn once i started uh with this company and really started testing stuff. Is you kind of learn what you can get away with and uh if you just upsize ducks slightly more than normal? You know your your static pressure goes way down and you don't have to use as many high performance fittings um, but no as far as just turning veins there in retrofits.

If, if you know what you're doing - and it's not that comp, you can kind of look and see how how's the air going to go um it. You know it's a good opportunity to fix some things that are um, that otherwise you'd have to replace and make bigger, um and and, like michael said again, the the radius uh. The throat is really what's important on elbows um and it really requires some space. So if you have a you know, if you need a tight turn, um and you're not going to be able to get that radius throat uh turning veins are are good for that um and a lot of times.

I don't even worry about the heel um. I just sometimes it's easier to draw a square and draw it and put some veins in it, but yeah the uh. I posted about this on facebook recently and it's really no uh benefit um. If the uh, the heel is, has a minimum benefit to uh to airflow when in comparison to the throat before we leave sort of the design side of this conversation, i wanted to ask you, michael about um russ king's software um.

If, if somebody wants to get into doing some duck design - and they want to follow manual d, would you would you suggest that, as a way for them to to get started, i actually haven't used it personally yet so i just wanted to. I have an either it's windows based, but it seems like the easiest on platform to some 3d modeling um and things like that. The i use sketchup and that's a little more advanced um, but it all kind of depends on what you're trying to do. I mean for me for the manual d design side i use a spreadsheet and so um when i know right.

Soft has manual d built in that's another big one, but these are all platforms that uh are windows based and i'm stubborn and refuse to use windows for anything so um, but yeah. I mean i first first on the quick model thing. I think they look awesome and it's uh reasonably priced, and so it also um does some stuff like um like or it it integrates with some florida energy code model deal, and so it may be beneficial to people in certain areas. I don't know yeah um i'll.

Just get uh i'll, get jenny and and russ on and have them have them do that that'd be a good idea we'll do that instead of me prattling on about something that i obviously don't know a thing about all right. So, let's get into some more of the um specifics of installation. So let's start with um, because you know both of you know something about metal, duct fabrication. I think probably michael's a little bit more uh does a little bit more of that than neil, but um.

You've both done a little bit on the channel on in a duck fabrication of different types, but let's start with on the metal side um. What are some of your you know if you're just gon na make uh, you know a simple transition uh on a supply or something like that? What are some things that you need to make sure that you're thinking about when doing that? Obviously, we're not gon na go step by step to the whole process. That's something that you have to learn through a lot of practice. But what are some mistakes that you commonly see, or some or some tips that you'd always want to give somebody who's going to be working with metal duct work? Maybe isn't super super confident with it? Well, my tip is uh, get it to off the shelf as quick as possible, so uh one transition to round or one transition to uh, something by eight inch, um that that's our uh, my my motto: um try to keep it as little custom as possible.

Now, if you're doing a retrofit, that's a little different and again i um i draw it up and have someone else make it, though i found michael's video on the transition really helpful, and i've done a few of those in the field um to the point now, Where i've done enough of them, um that i don't bother trying to measure that up, because sometimes that's a that's a difficult measurement to take where you're you're changing a bunch of stuff and to try - and you know, you're going you know from this size to this Size this way - and this way you got to be perfect, where, if you do it in the field um, it's not that difficult! You just do one side at a time i can uh michael, can probably speak to that better, but he's got a really good. Video out there yeah i mean so for i i would agree that you want to keep uh the custom fittings to a minimum uh. One other thing to look out for is you know, don't if you're doing a transition, that's offset. You also want to make that as large as you can is also better and and also easier to do, um, even though it's not always possible, but um i mean for us uh.

We always make our transitions and stuff in the field because, like neil said, it's things shift when you're uh actually putting something in and it may it's i've just found it a lot harder to get perfect or exactly right, and when you have to modify a fitting That was made can often take more time than just creating a transition or whatever real quick on site, and so that's why we've always done it. That way - and so i mean i feel, the method that i have is kind of foolproof and you can always get it right uh. It may take a little bit of time, but once you're comfortable with it, you can kind of do them pretty easily and so um that video is on the hvac school youtube page um. I forget what it's titled like: making a duck transition in the field or something along those lines: um uh, that's that's our method of doing it and what always works on changeouts um.

Now, on the return side, we have radius fittings made and - and things like that, we'll try to have that stuff pre-fabricate but uh when it comes to tying back into the supply plenum or something like that. That's where we just field cut, make them and it seems to work out better for us, because you can do it pretty quickly. Yeah, it's a lot easier to have one part of the duct syst like the uh that supply transition uh, you know unknown where you know what your return drop. You know what your transition to your filter is going to be.

You can get all that prepped up and then just leave like one fitting for field fab. Um is a kind of a pretty pretty good strategy, and another thing on that, too, is back to kind of the first thing we talked about about how important stuff is near: the equipment um, where you know you got to be careful with transitions and turns right Off the top of uh, you know on the supply a lot of times there there's not enough room. These newer air handlers are really big and uh. I've seen so many situations where even ones where we've been asked to do where we're like, i kind of want to turn this horizontal or something a lot.

You know, installers are very limited on what they can uh. You know how they can pivot in the field, but get it that first few feet of the supply funnel is extremely important if, if you can do gradual or make it big, it's really beneficial. Is that a baltimore raven right here? In the background, i think it's a pro. Is it um? It's nice out here.

It's probably about 85 85 degree, dew point you're not dripping yet yeah nerd talk all right so um. What are some rules of thumb on cross breaks and the use of canvas when, when do those come into play? And again, i'm literally talking out of ignorance here, because this is not something that that we deal with in residential, so uh when and where are those applied? Well, let me i'll jump in um, i'm a big fan of canvases for a few reasons, i'd like to decouple the equipment from the structure as much as possible, whether that's uh, you know on vibration, pads and then you know, try to put a canvas connector. As you know, on the supply and return as close as possible, um, and also i find with the canvas connector, it makes that one that last connection of duct um a lot easier to do um as far as cross breaking uh. You know it's kind of like a if you're, if you have like a 12 inch tall, uh fitting.

It's probably not. You know you probably don't need to cross break it as long as you're, not doing it with like some 30 gauge metal but yeah. Once you start getting uh larger uh pieces of metal and trying to avoid popping um you're going to want to reinforce it somehow and michael uh, you had uh i'm thinking of someone else. Someone else had a video there's, a tool, the hensley bender, or something like that.

It's actually, i made one um and it's really neat where you can kind of do bends in the middle of duct uh up to like 36 inches, where otherwise, if you're doing it in the field, you're gon na have to find something. You know pretty sturdy to bend the metal on, but when in doubt cross break it because it's pretty hard to uh. Well, it's not have you ever seen ducks with uh s-slips drilled into it and cross patterns. I i mean you can do the screwdriver trick so how we cross break them.

If they're already installed is, you know, take some straight edge and a big screwdriver and just scrape it across it and it creates a cross break. But for us i mean we're not we're basically never cross breaking anything in the field, but we're trying to keep our transition small and use. You know 26 gauge metal, um things like that um i mean you know, in my opinion, it's more of a like. I don't know how i can say this politically correct, but it's an i'm better than you kind of thing more than anything right so like if you have low static pressure and low velocity most likely your ducks not gon na bang.

So you know they're less beneficial, but they look sexy. So unless you don't line them up and they look like yeah, then they look like garbage, yeah yeah, but a lot of sheet metal shops. They have what they call beaded metal, so the metal, every foot or so has a bead in it, which essentially uh you know, makes it more rigid and uh. So a lot of when i purchase metal from a fabrication shop - it's not cross broke because the sheets of metal are beaded already yeah same with same with us would cross break would be more of something that we do ourselves or like the stock.

Rectangular ductus crawls broke a lot of times like they, whatever your eight by duct is and but right. So next i want to bring up neil's favorite topic of all time. Well, it's it's tied with air filters, but that is flex duct, because neil is in love with flex duct um he sleeps with flex duct it gets it gets really weird. Actually, i don't even want to tell you everything that i know about it, but um all right.

So let's talk a little bit about flex because i think and and i'm with you on this as well - that flex is actually a pretty good product if it's used properly and um just talk quickly kind of through your evolution of thought on that front, because i'm Sure you didn't start off being in love with with flex um. This is a relationship, that's developed. You know like a fine wine. Yes, i you know, i think, for the first.

I don't know 10 years of my career, i never installed any flex ever um. We we got a new service manager and he started installing flex so that those would be the run outs and we just kind of you know, threw it in there up size to the size and uh. We didn't measure anything so who knows how well worked uh? They didn't customers then call back. So i guess it was okay, but now moving to present day i mean we, i pretty much try to utilize flex as much as possible um, because it is uh leak free, it's well insulated.

It reduces noise. It's got a lot of a lot of benefits that rigid duck does not so the big knock on flex is uh airflow right, it's terrible for airflow, but if you um, if you pull it tight it, it literally is the same thing as rigid, like. I think two percent off um and uh, so i mean it - takes a little bit more um thought to do it like that and effort um, but uh yeah i mean we, we, i literally i i look for opportunities to put in flex uh and mainly it's Because of noise um because um, you know all metal duct system, you know it's just there's, there's a potential for noise where flex duct uh it does a good job. Speaking of that, i have a little uh project.

I'm uh i'm working on as soon as i find some time that uh i'm asking brian to help me with as far as publishing, and i think we're going to prove some people wrong as far as flex stuff goes, but i play it up a little bit. I don't i don't love it as much as you may think. I do, but i know it makes for good conversation online. So i'm welcome to uh.

I'm the flexed up defender i'll. Take that uh that weight, yeah yeah defending flex duct is right up there with um defending duct board, which reagan murphy recently did or defending goodman equipment um. Those three uh put you in unique territory, um so yeah and when neil says that it performs essentially the same as metal, that's based on testing, i mean that's, not that's not just something that we say. I mean that that's you actually tested and believe it or not.

You can actually test it. You know it really isn't impossible so uh which, when we get into the commissioning part, we'll talk a little bit more about that uh. What are your takes? Michael about flex, and maybe also some sort of your best practices is in terms of installation so that it does perform uh at its best yeah i mean you want to keep it straight for the most part straight and tight is flex. So obviously, you know we've all seen the flex systems that they just you know, take the whole box, don't even stretch it out and it's running and zigzags and craziness.

That's what gives flex a bad name and uh. So anything when installed improperly, it's not the product's fault, so i fall in kind of the category where i think flex is awesome as well. It's just often used poorly and so um. I come my a lot of my installation.

Experience was in commercial, and so we kind of used the same strategy. That was code, at least at the time that i did it in my area, which is keeping flex to about the last eight feet or so of a run for noise and um just easier to install a run versus like if you're doing a full metal run Out um, and so that's kind of my strategy with it in a lot of my designs, is, is taking the last five eight ten feet and using flex duct in that area of the run um. But obviously we also do stuff that, where the duct is more in a conditioned space, and so the insulation and stuff isn't as much of a consideration. Whereas if i'm putting ducts in attics, i'm going to try to use as much flex as i can, because insulating duct is hard and time consuming, yeah and difficult to get perfect, you know that's another big factor, especially if you're in a high dew point market like Ours, you, you have to make sure that every single inch of that ductwork is appropriately insulated, otherwise you're going to start getting sweating and other issues.

So that's another big advantage of flex, while i'm thinking about it. I wanted to ask both of you. If you are working with balancing dampers, because we touched on that quickly before i know both of you um, you know try to create pretty high performing duct systems in terms of leakage. How do you deal with balancing dampers so that they aren't these? You know leaky annoying things you know to work with, especially when you've got flex, it seems like they're, always you know a challenge with the arm and all that you have any kind of strategies there um in terms of how you how you deal with them.

I think neil's got this one well, this is a tale of two jobs um. So recently we did a job where we, it was a retrofit. It's not 95 percent of the duct system was new, but we were not able to uh redo the boots and we could not get the damp the registers with the dampers in that we liked. So we put balancing dampers uh at the take-offs and we had a 65 cfm of duct leakage right, which is very high for us, we're usually under 25, and when we want to show off, we can get it.

You know lower than that um. So it's just! It's like two holes for every system right, so our strategy, um, nine. Ninety five out of a hundred times is we're gon na put registers with opposable blade dampers on and we balance the system at the register. Uh the only real negative.

Well, there's two: i guess you could say. First of all, you should be using high performance, uh supply registers anyway, the ones that the five dollar ones at the supply house are they're they're, just not very good um. So if you know you can step your game up to like an extra 10 bucks register and you can get some really good ones um. So the downside to balancing at the at the uh register is potential for noise.

If you're going to take a six inch round and try to get 20 cfm out of it by dampering it down, it's it's going to make a little noise. But if you do it, you know decent duck design and you're within you know 20, 30 plus or minus uh it's negligible and it makes the balancing process a one-man job um with it with a flow hood, and it really speeds it up a lot and the Duck system is uh, naturally tighter for us, where uh, we don't do as many opposed blade dampers, even though we should, but a lot of my designs are uh also like performed by someone else, so i have a less say in kind of how it goes, but The ones for us when you're, using a um standard, uh damper in metal, duct or whatever is taking thumb, gum and once you've set it in position. You can thumb gum around the holes to make it more airtight. There are some also better dampers, like beefier commercial style, dampers with a hand, a bigger handle and stuff that have less leakage that you can deal with, but um a lot of the times we're buying takeoffs with dampers already in them and they're just kind of the Cheap style ones, and so we'll do thumb, gum around them um and that kind of helps with the leakage, but i'm also not shooting or or getting as low a duck leakage as neil is, but it often matters a little less in my area where i'm just Leaking it to the basement, anyways, so yeah.

Let me touch on that uh briefly, um is right. So what we do uh there's two methods, the one when i'm doing it and because i'm weird is you could take like one of those big blue uh wire nuts. Stick it on the back of it and then do and tape it so it'll still move freely, but in the wire nut, but it won't leak. So that's really weird - and i do that um, but you can also take like a couple of layers of mastic tape.

So you have like this big hatch, you know it's like the flex seal, you just slap it on the back loosely and then squeegee it down and um that helps as well but um but yeah uh. It's you you. Definitely! If you do not um do something. It's it's going to lead.

It's your uh! I don't know. I need a picture of this blue wire nut thing next time you do it. I need a picture. I have it somewhere and also i've gotten some crap, for this is uh, because it's not like uh astm rated or something but the uh.

The zip stretch tape that that people use for uh uh for um, like how zip the green uh barrier yeah. So i use that tape a lot and uh it's very stretchy um. So that's kind of how i finish that off ain't. Nobody got time for that.

So i understand that. So just put some mastic tape on it. Have you ever tried actually using flex seal? You know just just flex seal over that bad boy. You know after you get it after you get the dampers.

I fixed a drain pan with flex seal but never tried it on uh dampers, but yeah yeah might work. I don't know anyway, okay cool. So let's go into um strapping and routing, so we already talked a little bit about you know wherever possible. Well, i mean this is another thing it's like in our market and we still do it sometimes, but using you know triangles or you know, mixing boxes which i don't know why they call them that boxes rather than using uh.

You know y's or actual fittings um. So that's another big one and design that you can improve a lot and, like you already mentioned, if you're gon na, if you've got to make a 90 degree, turn well, then use a use, an actual fitting for that, but in terms of supporting strapping duct work. So that you're, not compressing insulation, that sort of thing you guys have any top strategies for that any sort of like special magic. Well, if it's insulated um, i like the the wider nylon, the black nylon strap, if possible, um, sometimes i'll i'll do a saddle under it uh i'll.

Take like a piece of bubble, wrap and uh. You know bunch it up just to help um but yeah. If it's in condition space it's in conditioned space, if it's insulated, it's probably not a big deal. If it's in the attic, you know you want to be careful, you don't want to bury ducks in a lot of places, especially in florida, so you're definitely going to want to strap it up.

Somehow one way to do it, it you know you got to what you're trying to do is avoid compression right. So it's a tricky balance of supporting the duct properly and then avoiding compression. So if it's flexed up you're gon na have to do it every four feet or so five feet, if it's metal duct, you can get away with a little bit farther span. Um you can use metal, strap uh before you insulate it or you can like leave a section uninsulated and then come back around it um.

If you're worried about um compression uh, we don't. We don't have as big of a conductation issue as you guys do, but it's real enough that we we have to um, be mindful, but i know you guys are it's just another level down there in terms of um? Actually, first off michael, do you have anything else to add to that i mean i kind of think that whole four foot thing is kind of a good rule for basically everything you know like every four or five feet, just strap it up and so uh, especially. I think, with flex duct the more the merrier to keep it straight and tight um a metal unless i'm using uh, you know spiral pipe. That comes in ten foot length like five foot, anyways right so or whatever so just strapping it.

Every four or five foot is probably a good rule of thumb for everything. Well, i don't. One of my tips too also is um. You know, especially this is more like a new construction.

Uh situation is to try to do as much of prepping on the ground. Um, where you're cutting you know your takeoffs you're sealing your takeoffs, you're, insulating, so um and then putting up duct in ten foot. Sections is not as big of a deal so then um, you, you know. If you look at the code book, i'm pretty confident in this, you don't have to strap metal duct more than every 10 feet um.

Maybe you could take yeah so um, but yeah. That's just a little. You know a little side, but again it's a good tip to do as much as you can on the ground. Yeah they just get heavy and stuff.

Once you get the takeoffs and stuff it's harder to do. Rectangular duct, in that fashion, duct is easier to do in 10. Foot sections, but you know yeah. I try to do as much roundup as possible.

I mean usually uh, head height is the determining factor, but you know roundups a lot faster, cheaper, easier to do less leaks, uh, just pretty better performing really yeah. It's just. It's got a lot of benefits to it in terms of duct leakage. Obviously you're the you're.

The king of uh of low uh duct leakage neil what are some of the areas that maybe get neglected um i mean. Obviously anybody can slap a bunch of mastic or duck sealant or pookie. If you prefer to call it that i prefer that you don't uh. Call it that uh as a sealing technique, but what are some of your maybe top techniques or things that you see that get missed um.

I i think takeoffs people um, like the airtights, we call them they, they uh rely too much on the uh. Let me back up: they rely too much on the gasket. The problem is no one tests it right, so they have no idea uh. I think a lot of people think they're doing a pretty good job with duct leakage until they actually start really testing it um.

So my trick is uh. It's first of all. It's a mindset where you want it not to leak and you're gon na have to you know, identify potential uh issues with that, but back to what i was just speaking on a minute ago, is by trying to do as much as possible. So if you know you're going to use 10 elbows go ahead and mastic those 10 elbows set them out in the sun.

Let them dry, for you know an hour or so your take offs paint them up just do as much prep work as as possible. If you're, if you're, first of all and again i get that not everyone has the opportunity to slow it down a little bit. But if you're um thoughtful with your order of operations a lot of times you you can stay busy and prep stuff. So where you know, if you're doing a several day job day, one and two it doesn't look like much is getting done and then day three is like.

Oh wow, like all that just happened because you you put in the prep work um. I've found that, if you're reactionary, if you're cutting stuff in place, sealing it in place, the uh, your your outcome is not going to be as good yeah. That's one of the things that uh eric melly uh talked about last week and actually in the podcast that we did together just doing as much as you can on the ground if you're gon na do anything off of a ladder, if you can do it on The ground you're going to be able to do it a much better job of it. So just in terms of prep and mindset on an installation just always thinking what you can do beforehand and what you can do on the ground, which you can prefab too.

As much as possible, i don't know that i mentioned this to either of you guys really to anyone yet, but it looks like we're gon na have our an opportunity to do. I don't know if opportunities the right word, but we're going to be doing some residential new construction for uh high production in a high production environment for the first time, and it was actually kind of an eye-opening thing, because when i used to do this years ago, Um and so there's sort of your standard flow. You know you're rough, your trim, your start um sort of set up, but but actually in this particular subdivision, they've, actually split it up into five steps in order to further optimize um every step in the construction process, because they're, essentially turning out houses start to finish. I think in eight weeks is their construction timeline um.

Some of you will know who the client is just based on that alone: um, but they're. You know industry-leading in terms of how fast they turn on houses and so um. But when you break it down into those kind of steps, you can actually start to do a pretty good job, because you get really optimized on exactly where everything's going. You know your penetrations everything that you're doing you're doing in this very orderly way, um, and so there are some advantages to kind of thinking of things.

In that way, you know efficiency is not. I guess my point being efficiency is not always a bad thing. It can actually uh lead to some better results in some cases in doing that, prep, work and prefabrication is a big part of that as much as you can even do. If you do it in a shop, do it in the shop before you even bring it to the job site in some cases, but same with design right where, like it's kind of a similar thing, you either, you know you're going to try to take your time Ahead of time and and think a lot of these things through before it's go time, and that makes go time much easier.

You know or you're just going to shoot from the hip and see what happens and that's kind of where our industry you know is where it is with lots of poor performing systems out there. You know so uh makes sense, but eight weeks is pretty quick on a house yeah for sure for sure yeah. The process is important, whether it's everyone's process and they all have to mold together whether it's you know the sales process, the install scheduling manager process and the installers, and everyone should have a process, and they all should kind of work together. On the mastic thing, too.

Uh neil was talking about setting it out in the sun, but one of the things that we do that works pretty well is like the battery powered fans or whatever you know that a lot of people will have or the floor dryer type of fans that plug In and so we'll set them near that, and it helps dry things quicker um. I would also say a lot of times like a thin coat and then a thicker coat does a really good job too. If you're able to break steps down in that way, where you can kind of put a thin coat on metal, duct work at least and then go back and hit it with you know, a little bit. Thicker coat tends to do a good kind of duck.

Sealing job because a lot of times, first time you hit it, i don't know if it's the oil on the ductwork or whatever it can crack and do some things that sometimes you need to hit it again. So all right! Well, i'm going to give you one another. One of my little secrets is a denatured alcohol, but you got to be weird to rub down your fittings before you mastic them, but uh. It does help with that.

I and i don't do it every time, but if it's really really bad um, i'm gon na you know try to wipe it down, especially if you're gon na use some kind of tape. Also where we use a lot of mastic tape. Also, i mean because it's not always practical to use mastic if you're, if you don't have time for it to dry. So if you're going to be insulating it a lot of times, we'll do mastic tape and go ahead and insulate it.

You know, especially it's like the last day on the job or again, it's like a one-day job kind of stay away from, because i don't it's just a rule of mine. I don't uh cover mastic way, because if you did a really good job with your vapor barrier and everything, it's probably gon na stay wet for a while yeah, that's actually a really good point and it goes against a lot of the standard practices that people use. Um, when installing flex especially is you know, there's a lot of slapping a wet beater mastic on and then covering it right up. Yeah yeah, it is a.

It is tough um. Let's, let's get to a couple questions. One of the questions that we had here um in in chat is jacob montgomery says i keep seeing boots and plaster frames that are loose in the ceiling. What do you do to drill the register grilles into place when the screws push up the frame and won't set um? So so that's one question to answer, but then also, if just talk a little bit about that leak point, you know the leak point where the boot hits the ceiling or where the boot hits the subfloor um.

How you, how you think about that a couple ways we just recently had to do this, where it was a one-day job uh we had to move a few ducks, a few uh registers and um. It wasn't really lining up where you could. You know take the plaster frame and secure it to the structure. So it's it's really a two-man job uh one person's up there uh kind of holding it down, and then you can take the register and kind of cinch it together.

Um. It's it's not ideal. Uh! Wouldn't do that if i didn't have to um another, you know you mentioned leak, point um. Another thing you can do.

Is you put like a bead of caulk around the plaster flame and drop it on the drywall and it does a real good job of sealing that um but yeah? Now that's a very important leak point is the boot to drywall or boot to subfloor connection. You can do it a few different ways if everything's clean, you know, mastic or caulk, i feel, is the best way you want to use some kind of caulk that has some flexibility to it if you're buying it at home depot, it's probably not very good.

14 thoughts on “Installation mindset / ducts, venting, & commissioning”
  1. Avataaar/Circle Created with python_avatars Pinky says:

    I’ve worked for 2, 3rd generation owners… translation.. has no install experience, knows enough of the terminology to sound somewhat competent… but.. everyone that works for him laughs him out of the room when discussing the trade.

  2. Avataaar/Circle Created with python_avatars Gostevo79 says:

    I guess this is kind of on topic. I’m charging a unit. My air handler is in a mechanical closet which has a cut out in the wall feeding return air into the mechanical room and then into the the unit. Do I take my indoor wet bulb to calculate superheat at the cut out on the inside of the building ? At the cut out on the inside of the mechanical room or right at the air filters at the unit ? Thanks !

  3. Avataaar/Circle Created with python_avatars Ty Branaman says:

    top key to comfort staying alive, – Bryan Orr that needs to be a T-shirt

  4. Avataaar/Circle Created with python_avatars Ty Branaman says:

    Neil Comparetto

    I built 2 Comparetto Cubes, they work great!

    Also creator of my favorite article the ten duct commandments plus a few more HVAC school ( links get deleted)

  5. Avataaar/Circle Created with python_avatars Jayzzz1234 says:

    Hi, can you put this to testo? can they make a small amp clamp around the same size as the gen11 pressure probes! Same size clamp jaw as kyoritsu 2200r if possible thanks.

  6. Avataaar/Circle Created with python_avatars Ty Branaman says:

    Michal Housh, Im known for… let me take over Michal is know for being awesome!

  7. Avataaar/Circle Created with python_avatars Nathan Hurst says:

    Even for guys who are not installers like the technicians should even be watching things like this so that you can broaden your diagnoses by know how a duct system should be installed and finding the actual reason why the system your working on is running a low suction pressure instead of just just charging the hell out of it to get it to come up.

  8. Avataaar/Circle Created with python_avatars tim westberry says:

    Did you pay these guys?
    I can train people for you
    Florida market

  9. Avataaar/Circle Created with python_avatars tim westberry says:

    Retrofit, RIP it out, measure all boot collars. Add all together with their .2 static cfms. Then you know if you need mods. And what your statics will be before you even start the job. Are you in Nepean ?

  10. Avataaar/Circle Created with python_avatars tim westberry says:

    Start at the end and work towards the AH.
    Design with .2 static
    Size ducts at .2
    Avoid 90's on trunk lines, straight through all mixing box's.
    Mastic all joints, hang everything
    Straight, and pull flex tight for statics
    Keep branches the same length for each mixing box. At least try.
    400 per ton, and let her RIP taterchip.

  11. Avataaar/Circle Created with python_avatars tim westberry says:

    Thin filters
    Seal your house
    Hire a maid
    85.00 cash or credit mam Service area Barrhaven??

  12. Avataaar/Circle Created with python_avatars Eassyheat/ Cooling says:

    Following the manufacturers instructions, and doing things in a workman like manner will go along way.
    I couldn't hang for the live but I did watch the whole stream.
    Thanks 😊
    Stay safe.
    Retired (werk'n)keyboard super tech. Wear your safety glasses.

  13. Avataaar/Circle Created with python_avatars A1 Beltran says:

    Good evening. Whats is the formula to calculate CFm to FPm. Question 2000cfm passing through 16×20 rectangular duct. What is the air velocity in feet per minute (fpm)?

  14. Avataaar/Circle Created with python_avatars Jason Nunes says:

    Do anyone thinks Hvac techs should have hazard pay, especially when doing pm with the filters????

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.