Surplus electronic parts :
Stock and Crypto AI Prediction :

Ed Janowiak of ACCA gives a presentation about Manual S and what it means to have proper airflow. He gave this presentation at the second annual HVACR Training Symposium. You can learn more about the 2022 HVACR Training Symposium at
While Manual J deals with residential load calculations, Manual S deals with residential equipment selection. The equipment’s goal should be to maintain 70 degrees in the winter and 75 degrees in the summer (with a 62-degree WB). These are not Manual J goals; they are goals of the entire residential design series (Manual J, Manual S, and Manual D).
When consulting codes, remember that those are MINIMUM standards. However, some of these codes refer to Manual J and Manual S, including IECC.
The sensible heat ratio (SHR) dictates the airflow you’ll need (CFM per ton). The location and equipment manufacturer can affect the SHR, but they do not determine the CFM per ton alone. You must perform a load calculation to separate sensible BTUs from latent BTUs. Then, you divide your sensible BTUs by total BTUs to yield a ratio.
Your equipment performance data will determine blower performance. The manufacturer publishes these data sets, including heating performance data and expanded cooling performance data. (Expanded performance data can also tell you the WB, which is important in terms of meeting your design goals.) Follow that guidance for equipment selection (Manual S).
You may have heard of the 400 CFM per ton rule of thumb, but it’s about as accurate as “beer-can cold.” It’s just a rule of thumb, and your calculations will help you get a more precise CFM target for equipment selection.
It’s easier to determine capacity on a heating system, as all BTU/h are sensible. However, some cooling BTUs are latent, which complicates the capacity equation. Most manufacturers give you the total and sensible BTU/h, so you may have to do some math to determine the latent BTU/h for your SHR.
Sensible heat ratio (SHR) tells us how many BTU/h are sensible out of the total BTU/h. For example, if you have 10,000 BTU/h with an SHR of 0.75, that means that 7,500 BTU/h are sensible and 2,500 are latent. When your SHR is higher, your capacity increases. Both the system and the house have a sensible heat ratio.
When determining the CFM per ton with SHR, you can use your temperature difference (TD) in that equation. Manual S has a chart that tells you the TD for a given SHR. In that equation, you divide your sensible BTU/h by the product of 1.1 and your TD. You may get a number that’s far higher than 400 CFM per ton! Once you figure out your CFM, you can size your equipment based on airflow, capacity, and oversizing guidelines. Remove any equipment that is short on capacity from consideration.
Manual S has 3 “N” sections, which refer to standards. N1 deals with definitions and general requirements, N2 deals with sizing limits, and N3 deals with OEM verification.
N1 emphasizes the importance of using OEM performance data. Do NOT use the AHRI equipment performance data for sizing. While AHRI’s figures are good for getting a general idea, no data can compare to the manufacturer’s expanded performance data when it comes to accuracy.
One of the most important tables in Manual S is Table N2-1 in section N2-5. It tells you how to select air conditioners for single-speed, two-speed, and variable-speed equipment. The table also gives you the minimum and maximum sizing ranges for air-to-air systems as a ratio, typically with a 0.9 minimum (90%) to 1.15-1.3 (115-130%). The same table for heat pumps is in section N2-6 (Table N2-2).
When adding a dehumidifier, keep in mind that the sizing value is based on 85% of the latent cooling load. When making conversions to pints per hour, you take the latent BTU/h and divide it by 1,054.
Overall, you must remember that Manual S says to meet the sensible and latent heat gains, but don’t exceed the total gain by 15% (single speed), 20% (two speed), or 30% (variable speed).
On the heating side, you need to be able to counter the sensible losses in the heat. If a heating system cannot put out enough BTU/h to exceed those losses, you may need to add another source of supplemental heat and recalculate the BTU/h output to see if it exceeds the losses. If the BTU/h in sensible gain exceeds the losses, then the system will run satisfactorily for most of the winter.
To find the heating load CFM, you take the furnace sensible output (BTU/h) and divide it by the product of 1.1 and the temperature rise (instead of TD in cooling systems).
Ed also covers:
Design software programs
Default TD values for CFM approximations
Sizing for budget systems
House SHR and leaky homes
Sensible losses in the winter
Modern furnace sizing
Read all the tech tips, take the quizzes, and find our handy calculators at

Hey thanks for watching in this video ed jonah walk the new manager of design education with akka congrats on order to him for getting that position actually between this time. The time that he gave this talk at the second annual hvacr symposium. But in this video ed's going to cover what proper airflow really means, so he's going to be talking a lot about system airflow and a lot about akka manual s. So i think you're going to get a lot out of this.

I know it's a little longer, but i think if you stick through it, you're going to learn something new, that you're going to be able to apply to the field. Hope you enjoy were the guys yesterday walking up to the camera and getting too close, because i got to be the first guy. That does that. I want to say hi to everybody at home and i don't know if you're watching me live or recorded.

But you came to the right place. All right, i got ta admit i got ta, do stuff, that's funny and entertaining because i'm really not that bright when it comes to delivering the material. So when you walk out of here, i either want you to say. Oh, i understand what he was talking about a little bit better, or maybe it's going to be.

I don't know what he was talking about, but that was pretty good and i've been making a living at doing that for a long time. All because i happened to show up at a class that i was required to attend and the instructor didn't show up, they asked me, you know, can you do the class and i'm like i've sat in it on it? You know 10 or 12 times delivered the content. The next day, harry called bill harry said to bill. How did that do last night and i quote bill chu said well harry.

It didn't suck that was 22 years 23 years ago. Something like that. So that's how i got doing what i'm doing so, i'm going to go through my favorite topic and, of course that's who i am that's me, uh i'm employed by a non-profit and we predominantly take care of the new jersey area. We get funding from our local utility programs, but i've been contracted to work.

I've done stuff in california. I've done stuff down here in florida. I work all over the place, essentially, who will ever give me money? I've also been doing some stuff with tec. If you're familiar with the folks at tec, they have some really good stuff.

That's just coming out right now, so you should pay attention to that. If you're on social media - and you recognize that picture, you might put two and two together with it. That's me and uncle leon in 1966. He was trying to get me to smoke back then, and i guess he was successful.

So if i was at this event last year and i knew like four people - and i started with this - and people uh now - i know who a bunch of these people are and it makes it a little bit better, but at the same time it's i'm still Me so it's the way it is. I've been doing this for a long time, i'm a licensed contractor in my state. I do a lot of ceu classes for not just new jersey. I got hooked up with a bunch of people, i'm a cu provider out in oklahoma and idaho and iowa, and a bunch of these people that talk funny and they say i talk funny.

I don't think i sound like i'm from new york, no right because i'm from jersey, but i'm from the good part of jersey, you know the southern part. I feel just as comfortable doing something for one of my local utilities, as i do down in the basement. Installing ductwork, but i get the pleasure of doing stuff on a national basis and i guess this would be considered considered a national. But it's been a running joke because i've been saying to my kids since she was little.

You know your dad's, nationally known and two years ago for christmas. I got one of those placards that you stick on your desk and it had my name and job title and underneath it it says nationally known, and she just rolls her eyes so and that it's what it's all about when you have kids right, making their eyes Roll and if you do have the availability come back when i do the next one, because i build on those those photographs all right. What we're going to talk about is not manual j. What we're going to talk about is manual.

S, be honest. Have you ever even heard of manuel s? Yeah we had a couple of people and i i started talking about this before we officially started, and i i mean i don't regret much in life and when i say i regret doing what i did. I do i'm not heartbroken over it, but if somebody explains the manual j process to you and doesn't talk at least a little bit about manual s they're doing you a disservice. If you're in a heating, only climate manual, s doesn't have to exist.

If you don't want it to because when we deal in hot air or hot water, it's all sensible btus, that's really easy to digest. What has happened is a lot of people have looked at air conditioning in the same light, and it's not even close humid green grass arid. Where are you at you're, local, so yeah you deal with living? Well, we call it living in a basement. That's a in-ground underground swimming pool in this market right, so it's you're dealing slab on grade.

Typically, so you can live in a cave then, even though it's you know above grade it's disgusting to be in a house, that's humid! I mean we can all get agree with that we're going to have to make in my mind what i make people do is make them make a conscious decision to what is more important to them and is it on the hottest day of the year. Do you want to maintain some number or the majority of the days during the year? Do you want to maintain what we describe as comfort? So that's a conscious decision. Can you get both if you want to spend more money, it's easy to get both, but do most people want to spend more money and, and they don't so, if we follow the guidance we can sort of protect ourselves, you guys ready i'm going to go through A lot of information, and i'm stealing this from alex uh alex meany's the right soft dude. He calls himself a steamroller of information.

I am not trying to teach this stuff to you today because i can't it's way too much information, but as we go through you're going to start seeing trends and basically the trend i'm trying to set with you is, you got to look at the numbers and The numbers mean something and the first two times the first three times you go through the math of this you're, just going to be pissed off right. It's a you're eating lunch plates gon na meet wall. I've broken keyboard, i'm a venter. If something bugs me, i take the the keyboard i literally have, when staples has them for five bucks.

I'll buy three of them and i just get really because i can't do this anymore, because i have the tray that slides out from under my desk and it breaks the screws pull through the fake wood for my ikea desk. And then i'm sitting there with the keyboard on my knees - and i don't do good like i - take the keyboard and do this right, but then i'm fine, i plug a new one in i'm right back to work. My daughter will come down the basement, stairs and see keys on the floor and just go like this. You won't even ask it only happens once a year, but you know it makes me feel better.

So that's just the way it goes. If you guys have questions, stop me, i may or may not answer you. It depends on where i'm at so see how it goes. We might get through half of my presentation we might get through all of it.

I'm used to doing a class 30 times and by the 25th or 10th, i'm really good at it. First, two, maybe not so good, but we're going to see what happens. What are our goals? 70 degrees in the winter time? That's our target! That's what we want to maintain inside the house: summertime 75 degrees, a 62 degree wet bulb most markets, green grass, 75 degrees in the house, 50 relative humidity, depending on the county, where we are, are right. Now i've done some work for some local contractors down here.

Some of the counties - it's 55 percent relative humidity - is our target, some of them it's 50., it's whether you're actually designated a humid climate or a green grass climate, and i think right where we're at you can have across the street, be one and versus the other. So you got to look it up, but that's a realistic goal and it's a goal on a design day and that's a hard stop. In other words, we're tasked with maintaining a specific set of conditions on a design day. Anything beyond that's gravy code, your your local code - and i think it's in here it specifically says uh or the code will dictate now.

I i think we're going to get to actual piece of paper that talks about that. Yes, sir, i have no idea what that is, the colorado, co manual s doesn't go away, there's still things that are rel. This is for the colorado, dude who's asking about heating and manual s. There is still guidance and when i say guidance, i'm going to use the word guidance and i'm going to also explain it in a minute about code compliancy, and there are still things even if we're only heating that we're still supposed to follow the rules.

As per manual s, is this a manual j goal that we're seeing here and specifically it's not it's a design series goal. You can't say i'm going to follow the rules in manual j and then stop because that's not how it works. It's that 1.8 ton gain a two ton unit. Isn't big enough thing, got to use the guidance in manual s to answer that question? So it's a design series.

It's it's a it's all or nothing. You know. Do the 500 square foot per ton and a 0.1 friction rate for everything or follow the design series? Don't cherry-pick something that's convenient because you're not going to end up with what we're we're after it's a whole bunch of books is really what it comes down to and if we have time at the end, i'm actually going to walk you through the design series. But i highly doubt we're going to get there, but we'll see how it works out for the it guy.

Do you have any idea? Are people gon na have access to my presentation other than the live stream? Okay, uh at the end or somewhere you're gon na find a way to contact me. I always share my stuff i'll, never put stuff out uh at something like this and not share it. So unless it's copyrighted and if i stole it from somebody oops so they're the important books, if you're a residential guy manual, j manuel s, manuel d after lunch, i'm going to be doing the same sort of deal with manual d. So when we talk about codes, i'm not going to read the whole thing, because i want to stop right here.

Codes are minimums. That's it should you go beyond code? Yes, if the only way you can be profitable is to do minimum code go ahead, because what's the most important thing we do in our industry say, make a profit make money, because if we're not making money, we can't impart all these good practices. So we got to make money first right, there's nothing wrong with making money if you're lucky - and i i have a bias with this. If you're lucky, you live in part of the country where they follow the international code council rules, if you're unlucky iatmo, is what they're following i've argued with the iatmo people, because they want to limit flex and that's dumb right as long as you pull flex tight.

It's good, if you do this depending on how much you do this. There is some predictability, but not a lot and they want to get rid of flex. I don't agree with that, but we're supposed to follow whatever code is local to you. There's language in the icc codes right: that's uh, the energy code, they're, saying manual, j manual s, it's it's in the codes! All right! Akka has this stuff available for you.

What should the code official actually be asking for it's in print? So if you've ever uttered the phrase that inspector's an idiot, he was asking me for a whole bunch of stuff that hard stop again it's in print. They want to know very specific information. It's the minimum amount of information that you need to do a proper load, calculation, equipment, selection and duct design. So what i have found and again i work for uh - you guys are familiar with acca right.

I work for a mini version of them right, like a state version versus a national version of it, and i get phone calls on the regular from contractors where they'll say spectre's an idiot. He wanted me to put r8 ductwork in the attic and i'm like. Have you ever read the code? Huh yeah, it's it's just enforcing the code. I would say 75 of the time.

People are reactive instead of proactive and i'm not going to ask you to raise your hand, but the last time you had to do something and be code compliant, because you got called out on it. Was it because the inspector was right or wrong. I mean don't get me wrong, there's some flat out nitwits in my neighborhood that are code officials, and i say that more or less than just because it's not fair because he's an electrical inspector but he's tasked with hvac stuff. He doesn't know what any of this stuff is.

So if you fill this stuff out, there's numbers in there well, there's a chance we'll pass it through might be wrong. I mean i've put in duct plans with two inch main trunks and 60 inch branch runs. They all get approved, but i know what bob is looking for: he's looking for thickness right, he's not looking for accuracy, and this is all the stuff. This is why i asked if the participants online or in person you can look through this stuff or you can go on the ako website and literally type in uh code.

Compliancy and it'll. Take you to a link and you can look at the specifics of the stuff that they're asking for, but it's they're asking for available static pressure. That's one of the things that every time i see somebody given a ballpark or a rule of thumb, for what your friction rate's supposed to be, if you're designing a duct system without knowing what your available static pressure is how in the world, can you design a Duct system, if you understood what i just said, then i don't care if you show up after lunch, if you don't know what i just said, you better be in here after lunch. So that's the way it goes.

I'm not going to be able to teach you these things in the amount of time that we have, but if you know the difference between sensible btus and latent btus, with what i'm going to cover today, you should have at least an insight to what manual s Says, or even better, if you're already following the guidance in that book, you're going to be doing i'm doing what ed says and if your arms long enough do one of these or come up and say you know what i was with you the whole time and I'll won't be avert, while the virtual guys i'll have to do it. That way too, maybe at the end i'll come back and maybe behind the camera. But you won't be able to see that. But can you guys figure out? It's been almost a year since i've done this in front of live people and more than half of the the web webinars.

I do i'm looking at myself in the screen. That's a scary! I got three monitors. I got to put me all the way over here, because i don't want to look at this. I feel sorry for you, man, you're so close, but it's just the way it works out, but yeah once in a while.

I do them and i can see the people but - and i don't want to see you guys either on people laying back in their freaking recliners and eating bigger bellies than mine and it's falling down the food's falling down it's rough. So i'm enjoying this, maybe more than you are so yay me all right. I don't care if you follow codes or not if it's a conscious decision that you're going to ignore them. Fine, if it's purple purposeful defiance, remember that you might be in a situation where you don't want to be, and i'm going to say, probably half the country it it's not applicable.

Where i live, it's very applicable and if you purposely ignore it right, it's no defense. I didn't know and you're putting yourself in the butt kicking line. If you get caught, my state is horrible about stuff. You do a job for 10 grand for a customer and you're found not in compliance with the consumer fraud act.

There's no argument you're, not in compliance. They can collect three times the cost of the job. So you're you not only did all that work for free and gave them the equipment you're, giving them 30k on top of it, and it happens and there's homeowners that play contractors and if they don't follow the rules, it's their own fault. So i do feel sorry for him a little bit, but if you're not going to follow the rules, you know the game.

If you're you got to play the game right. Predictability, i'm not going to say code. Compliance will give us complete predictability, but it puts us on the path to predictability. Do the math up front and the systems are going to work.

I mean that's really the way it works out, at least in my mind. I like this chart, because i have people that i know that are smart people, people who i respect their opinion, but they'll tell me that your airflow is supposed to be based off of a chart. That looks similar to that. I know a guy who said something about he lived in an area that he considered a humid climate and he was talking about some place.

That's up here and when i got up off the floor from laughing, i explained to him: that's not a humid climate right. The sensible heat ratio of the structure dictates what our airflow is supposed to be. Now it gets a little bit deeper than that. It's the extended performance data versus the air flow, that's recommended, but ultimately, what do we want to do? We want to meet the sensible load.

We want to meet the latent load. We don't want to exceed the total load by 15, 20 or 30 percent 15 single stage equipment, 20 percent two-stage equipment. 30. If it's a variable compressor, we can go home.

Now that's manual s in a nutshell: don't over size, your furnaces by more than uh 140 percent to the calculated loss right, that's it! But the gap is. Do you know how to read extended performance data? I would say, on average half the attendees of any of the classes. I do on manual s, don't even know what extended performance data is. Let's take it a step further, it's not uncommon for 20 percent of the people attending my session are sales people for distributors and they are the people that you order, equipment from, because people historically have ordered equipment based off of tons and that's stupid and that's stupid Right, that's not how you do it if you're working for somebody right and they're paying you 50 bucks an hour, do you want him to use exact math on payday yeah, or do you want to ballpark it yeah i'll? Give you a few bucks right.

That's all this is it's math and i think it cracks me up. I'm a vo-tech guy and i wasn't very good in school and here i'm teaching math and the people i grew up with. They said you do what and i'm like yeah i teach math. I do i teach i teach third grade, math and sixth grade science to the butt crack brigade.

I mean that's really what i do and you can and this this isn't condescending. This is encouraging. You can be in the top 10 percent of your industry by following the simple third grade: math and sixth grade science, that these books now there are some real brainiacs that put a lot of this information together right for people like me to to share, and it's It's not difficult, you got to put a little bit effort into it, but when you get a call back on a job, that's under warranty do you get paid for it, no, and that we want to avoid that and that's what all this stuff helps: sensible heat Ratio dictates our air flow, we do a load calculation, it separates sensible and latent btus. We take our total btus and divide it into our sensible btus, and that tells us the sensible heat ratio of the structure.

That's all it is if you're using right soft you're using elite you're using the energy gauge with quick model any of those programs somewhere on that page. It tells you your sensible heat ratio. They might use different language, but they're telling you it because all this stuff comes from the same book right manual, j, it's where it all starts, and these are actually. These are the good uh copy and paste out of the book.

When i actually got a pdf version of the book, you can see where i took pictures with my phone and embedded them in these, because that's i'm a mechanic right. I don't have the ability to do this stuff precisely so it's kind of the way it works out, but they're telling us look at the extended performance data. I know people that have been responsible for selecting, hundreds and hundreds and hundreds of systems, and they don't know what extended performance data is that's messed up right. Do you want the guy fixing your car not to know the difference between ford and chevy? It's what it is so what it's coming back to is the design series says uh, look at your blower data.

Look at your extended performance data and follow the guidance in that book that that book can be a little bit intimidating, but it shouldn't be and i'll explain why in a second, so what does the s and manual s actually stand for? It stands for selection. I heard somebody say that excellent cooling systems it gives us help heating systems. It gives us help help as in guidance. Forced air systems is specifically what it addresses it gets into hydronics a little bit, but it's it stops uh to a certain extent hydronics.

I got guys that do boilers in your market is it commonplace for the domestic requirement to exceed the space heating requirements? And that's me too: i don't live in a cold area. My design temperature is 13 degrees, but i have a 45 000 b2 loss on my house, but i have about a 90 000 b2 domestic requirement. We got the human car wash and the master suite and two other showers want to be able to run all showers at the same time and we can with that kind of capacity, and it's a you know good way to do things in my opinion. But it's also compliant as far as what manual s requires there.

It is, if you're doing 400 cfm per ton. I can't emphasize it more. You guys know what bcc stands for. Don't you? You guys know that right, it's beer can cold.

I can't tell you how many times people will puff their cheddar yeah. I got my measure quick and i got it. What's your airflow. Well, it's 400 cfm per ton.

It's you might as well be grabbing that suction line, saying it's. The proper temperature people are focused on things right and that's good. They want to be precise about that stuff. I embrace that, but you got to do it all right.

So it's i said this in my preamble before we technically started. This is the trifold that aka puts out there and it's a little bit dated because it is actually referencing and i'm so happy that didn't scream. I thought when i got close to that was going to break my eardrums. This is the old version.

I don't have any of the new versions with me to give away, but before we leave there's a secret i'll tell you three people are going to get these and they're the old ones. The idea behind it still the same. It doesn't have as much good information or current information, but it's the idea is the same with that book. This is written based off of that book, but if i can explain everything about the guidance of manual s with regards to air conditioners in that little bit of text, you think it's a pretty simple concept.

It is right. That's the whole point behind this, and that's it and that's it right here, i'm not going to go through it here again. This is for, if somebody's looking at this in a pdf format or whatever they can follow along capacity, heating's easy right, because all the btus are sensible air conditioning not nearly as easy, because we dropped the temperature with some of the btus and we let the water Suck the water out of the air with the other btus is measuring latent btus easy, a pints, a pound, get that air conditioner at steady state fill this bottle up you're at the barbecue. You got your slides on right.

You got somebody who doesn't care about what you do for work, but if you can tell them i just and it they pissed me off. They made me angry when they did the thing they went to uh 500 milliliters it is. They used to be 16 ounces. It's 16.9 and it messed my mouth up, um, i'm bitter a pints, a pound and not exactly, but it's close enough.

You take a red solo cup, fill it up in 15 minutes, there's 4. 000 btus. You think i like to quantify stuff. I got a little bit too much extra time on my hands, but that's how you measure stuff.

I actually had a distributor as i was ready, fill in my red solo cup. Uh use some colorful language and called me an idiot because it was a dehumidification with a particular piece of equipment problem and they didn't understand what i was doing and i said well all right. If you don't like the red solo cup, let's go. Look at my two digital hygrometers and my app to show you that the humidity removal, this piece of equipment is definitely subpar.

So this is the you know the bubble way to measure latent removal or you can do it with. You know sophistication, i'm not a pinkies out kind of guy, i'm a red solo cup kind of guy. So what happens if you're uh you don't have you can weigh it? Half a pound would be 500 btus, but it's not that precise of a measurement. So what i'm going to do is stick to my digital hycrometers.

I am going to stick my pinky out that day, so i was really fortunate and i alluded to this a little bit ago. I was measuring performance on equipment 25 years ago, where the only thing that i was using to measure the performance of the equipment was four thermocouple type. Thermometer leads uh, two with cotton, wicks on them, dunked in water and two dry bulb ones, and i was plotting a psychometric chart. The only thing i had that was even close to a computer was a solar powered calculator and i had my maglite in my mouth and the crawl space.

So i could power it up, but i know the cfm times change in enthalpy times 4.5 or if i want to be fancy 4.45 to compensate for density. I can tell you all those formulas, the amps times volts divided by delta t times 3.16, because if you did it 800 times it would be burned into your brain too. So it's not that i'm not smart, i'm really good with repetition. So, that's why i have to read things three times to understand it.

It put things in perspective. I was the guy in ninth grade that was in remedial reading and i don't know if i wear that proudly or not at this point in my life it might make you suspect, to what i'm telling you, but it's the truth. It's me nothing. I can do about it and you know: do the best you can with what you got.

Beer can cold if you're selecting it solely on tons. It's just the way it is you guys get the difference between nominal numbers and actual num actual numbers right. Excuse me two and three tons based off of our model numbers. Do they really produce that we see numbers like that are far more common? It's it's real life, it's what we can do.

Are you guys familiar with that chart right there or something that's akin to it if you're looking at extended performance data, that's what you're looking at this is a piece of equipment, and i can't remember if this is three or four years old or it for all. I know this could be 20 years old. Does it matter? No? I was on the phone with a guy from dc the other day, and we were talking about some stuff with manual t. You guys familiar with manual t it's the book for girls and registers, and he said i want you to put some stuff together for that and i'm like.

Oh, is this virtual or live you said? Well, it's eventually going to be live and i'm like i got to get my leisure suit out right. You get. The reference manual t was written in 75 76. Something like that.

Have the properties of air changed in the last 50 years, no property's there. No! So, even though it looks very dated well when you look at spread and throw and and uh terminal velocity of registers, it's the same right nobody's reinvented the wheel when it comes to spreading or throwing air. So i, if i got ta, go to the the thrift store. I am showing up for that in a leisure suit, because i thought that would be pretty cool and what the gentleman has said and you're chris's dad correct.

So i'm going to refer to you as chris's dad that's the way when i was growing up. That's how you always did it. He was saying with different refrigerants, or were these uh three uh, 400 cfm per ton or 350, and specifically what you're, quoting are rules of thumb. You can find this stuff, like this extended performance data, i'm going to say this is for a piece of r22 equipment.

If i remember correctly so, if i got any super geeks at home, that can look at a. I believe this is fetters or a york product. They can look at that and tell me how old it is. This is definitely a york-based product.

I think it was from the fetters line, but i can tell you that the what your airflow per ton had absolutely nothing to do with the refrigerant in it. Now you might have went to your local supplier and that's what they taught you and i'm going to say. Don't trust anything. They tell you for the rest of your life, no advice on finances, pregnancy relationships because they they're not following the rules.

These are the rules period. This manufacturer is telling us what our capacity for this 030 and o24. This is a two ton system. I don't care if that's a nominal two and a half ton coil, there's no such thing as a two and a half ton coil.

There's two pieces of equipment when you put them together, make a predictable amount of capacity, and that capacity is manipulated based off of how many cfm we move across the evaporator coil. This is four and a quarter per nominal ton. This is 400 cfm per nominal ton. This is 375 per nominal ton.

What manual s tells us is, if you slow, the fan down. Your latent capacity is going to increase. Your total capacity is going to decrease. Your sensible capacity is going to decrease and that's exactly what's going to happen.

This is all with reference to our design conditions inside the house, 75 degrees and 50 relative humidity we're going to use 85 degrees as our design temperature. You guys work in any markets where the design temperature is 85 degrees. I do it's called the east end of long island right. You have any idea who lives on the east end of long island, uber, rich people, people that are easy to cheese off right.

They want everything that they want. It's the house that you were describing earlier. So we have contractors that want to design at 100 degrees, even though that's not even close to what's required and their heads explode when i tell them 85 degrees. It's just like the plumber from queens that wants to design a boiler at -4, even though their design temperature is closer to 20 degrees.

It's just so much fun, so enjoyable at this set of design conditions right 85 degrees outside 850 total cfm. This is my total capacity at 23 4 sensible capacity of 19 000. We have 4 400 b2s of layton. Most manufacturers give you total and sensible.

You have to do some math to determine your latent as you slow, the blower down total and sensible drop. Our latent increases - and it happens again as we slow this down. This is math. This is physics.

This is how air conditioners work doesn't matter if it's hotter, outside or colder outside. This is the way it works, slow. The fan down, we get more late. Now we don't arbitrarily pick the lowest airflow because you're in marathon, you don't arbitrarily pick the highest airflow because you're in phoenix you pick the piece of equipment that meets the sensible meets.

The latent doesn't exceed the total by 15, 20 or 30 percent single stage. Compressor. Two-Stage compressor vrv by the end, i'm gon na, have everybody chanting that, yes, sir we're going to get there? It's an excellent question. What the gentleman was asking you look like a gentleman, so it's a compliment.

He was asking: how does this stuff all work? We have to go through the whole process. Now. Are you guys familiar with this mini split stuff? I have a love hate relationship with it because when i was exposed to this stuff in the beginning, i had a bunch of people saying put this stuff in and the humidity will take care of itself. I'm sticking up a finger right here to everybody that told me that right, because it's not true my whole thing is a salesperson - can tell you something: okay, i believe it but show me the math, i'm a math guy, that's the math right! If you can prove it it'll happen, if you can't show me the math, i don't believe you and with this style of equipment, i'm going to say in its infancy in my market they were trying to put in pieces of equipment that would heat and cool and To do that, they oversized the crap out of it and you lived in a cave and they had horrific failures with it, but they got up to speed they monkeyed with some stuff.

They put a compressor that they can run a lot faster, but they put a smaller capacity on it, air conditioning wise and they can prove the math and it does what it's supposed to and it's a fabulous product. But they can show you the math now, because they did what needed to be done. Their extended performance data gets so detailed. What components you use to build the system - and these are those little air handlers with a branch box and a piece of equipment outside they're.

Not only taking everything into account like line set lengths and all that to give you the capacity of it they're the only manufacturer. I know that publishes that and it's a little number up there and i'm going to circle it and there's my wow. This is impressive. A 62.5 degree wet bulb, your manufacturer might publish all their stuff at a 63 degree, wet bulb.

The manufacturer i predominantly use uses a 62 degree, wet bulb 75 degrees. At 50 percent. Relative humidity works out on a digital psychometric chart to 62 and a half some manufacturers typically round down some round up their jockeys are so tight. They go out to a tenth of a degree fantastic, you know, that's they get a big effort.

I like looking at their extended performance data because they have the kind of detail that i think everybody should have now. I know guys that are actual application. Engineers and they're, like i don't know why we publish this. Nobody looks at us, you know they're, like the dentists, their suicide rates higher than anybody else, because they're unloved they're worse than i made that up and that's not a funny topic, but i think well from jersey.

It's inappropriate in me always comes out. Let's talk about these guys, i have my own brand right. That's fred's! You got to understand sensible heat ratio. I've dropped that acronym a few times or said: shr 10 000 btus you.

It will acknowledge that that comes in 10k. Potentially right. I used to have a picture of a window unit, but this is the contemporary version of this slide if it's operating at a 0.75 sensible heat ratio, if you have a unitary split, your favorite third, well, i guess down here: they don't have 13s here your 14 Or 15 seer unitary split run at the magic 400 cfm per ton. It's going to have a sensible heat ratio on that extended performance.

Data 0.4, 0.74, 0.75, 0.76 couple of three percent in either direction. That's how they work if it's operating it being the 10k unit. At a 0.75 sensible heat ratio, 7 500 btus of its capacity is going to drop temperature in the air. 2500 btus is going to be ringing water out every hour.

I'm going to fill this up two and a half times see the way i everybody can relate to that. It's just math, maybe math you're not used to doing, but it's just math manual. S gives us guidance and it tells us if we manipulate the air flow. We can change the sensible heat ratio, just like we saw on that chart earlier, airflow goes up, total capacity goes up, layton goes down, efficiency goes up, and so does our sensible capacity and as chris's dad said, layton goes down.

So one of the important things when we talk about that is sometimes people don't pay attention to the fact that efficiency is going down where efficiency is going up with the bigger airflow. So, conversely, when the sensible heat ratio goes down, total capacity goes down. Sensible capacity goes down, we do enjoy more late removal, but our efficiency goes down when somebody arbitrarily starts off the whole process at 350 per ton, they're waving those two individual fingers in the air and saying i don't care about energy efficiency. So if you're in a wet market - and you just design it 350, a ton whether it's intentional or not, you're designing a system that is going to be less efficient and if you don't care about efficiency.

Well, then, that's fine, but if you do, let's follow the math, follow the process and get those predictable results. We also have to remember that a house has a sensible heat ratio for cooling, the leakier, the house, the more waters in it, and we will benefit from that lower airflow. I look at things definitely different than the the genery's market right. He lives in an area where you run heat, what six hours a season - maybe three so there's not a lot of heating going on, so the latent removal is probably his biggest concern.

I have days i have it on my app from this past summer. I was playing golf one day and i had a 84 degree. Dew point: that's disgusting. I mean i was playing golf, so it didn't matter, but i was sweaty a little uncomfortable.

I would rather not be that that humid. So i know what it's like to deal with those conditions and i might have to deal with it on two days back to back. You know 10 times for a whole summer, but 75 76 77 degree dew points for two weeks. Straight is a thing that happens.

Doesn't happen for six months, but it's something that does happen so when we have a leaky house we're going to have more water in it, so it might be more appropriate to have the lower airflow, but we're going to let the sensible heat ratio of the house Dictate what our airflow is going to be, then we're going to look at the extended performance data at those air flows, and this is the question that you asked and we're eventually going to get there we're going to look at manual s itself. What's 10 plus 10 plus 2, there's 22 pages that are the standard in the book. Is there a lot of good information in the book? Yes, for you guys that live in heating climates, there's all kinds of guidance on economic balance, points and just a lot of really good reference stuff. But if your main goal is being code compliant, there's 22 pages and two of the pages you're never going to do so, it backs down to 20 pages and i'm going to cherry pick like four of them and if you want predictability following the standard they're, the Only ones you need to look at do i recommend you read the book and investigate it in its entirety.

Absolutely there's a lot of knowledge to be gained from it. That's what the book looks like it's intimidating, that's what the standard looks like, and i would like to think that it's not as intimidating right, there's, not a lot digested on. I do have enough time today to cover that and while i'm saying that time, i started at 8 30 right. How much more time do i have okay? So can you guys at 15 minute in increments wave to me because um, actually, i'm doing pretty good? I'm 35 of 131.

so because i suck at this timing thing right, i don't know i'm bad at math right, i've done classes where and it i can do whatever i want most of the time which is going to kind of change for me a little bit Which i'm kind of saddened by but at the same time i've done classes where i have 100 slides that i want to use and we're done and i'm like slide six and i realized i talked about my family for an hour and a half. I hope they got their money's worth. I enjoyed myself so, and i think that's is that the most important thing, maybe i don't know, can you tell this? Is the first live class i've done in a while? You know in person. It feels good feels real good hope feels is good for you guys, though yeah i'm really.

I care more about me, but you know it's just the way. No, i that's not true i'll i'll. Stop myself to sleep. What's that explanations, yeah! It's it's things that you this is things that, if you're following code compliancy, they use specific words like shall uh, not a strong word must strong.

Word must right to be to be within compliance of what the standard says. You must do this yeah, but there's some really solid guidance or i'll call. It advice in the other sections and well, they call the appendixes. So the a section yeah and i'm that weird dude that reads the appendixes of everything.

So it's you guys go to the beach go to the lake, go to the place where the kids play, and you know your wife does what she does and either you sit in the bar and get hammered or you find entertainment. I can't read for fiction. I can watch movies that are, i can't read fiction. I literally take code books, this stuff and i'm the guy sitting there reading the code book.

So when somebody asks me a question and i'm saying 4.1.301, is you don't put screws longer than an eighth of an inch in a dryer vent? Something there's something wrong with you yeah, but not my market, because i said the exact same thing that you did and somebody schooled me showed me that update 18 mechanical code you're supposed to put fasteners in there, no more than an eighth of an inch in length. Yeah, i'm i'm with you until i write in the book and what the book says what the book says. So in the end section it basically tells us not to oversize stuff. It also tells us know how many btus your equipment can deliver.

Where do we get the information that our equipment can deliver that extended performance data? You see how easy this stuff really is and i'm yelling use the proper source. This is out of the original manual s and i'm not going to read it verbatim, but it essentially says: don't use the ahri information to select your equipment. Who's designing for 80 degree houses at 95 degrees outside nobody right, so don't use the ahri information use the expanded performance data from your manufacturer. There are just completely bizarre scenarios where there's a couple of manufacturers where it's very difficult to get the information for their equipment.

What but that exists, so you can use one of the aca speed sheets and it will manipulate the numbers from the hri conditions to simulate your set of conditions. Are you carrier guys? Okay, i don't know how carrier guys you have the carrier or whatever. It is, you can put your equipment matches in and it spits out all the information. It's some manufacturers do it that way.

Some have i've shamed, the sales people from my local distributors to provide their client base with excel spreadsheets, with all the information based off what they have in stock, which they hate me right, but the worst part is all they do is contact the factory. The factory already has this stuff and then that guy who's brow beaten in that little closet in the back says: hey ed thanks. Somebody actually asked me for all this. You know effort i put into making these spreadsheets i'm gon na learn how to make a spreadsheet someday.

I know how to use them. Kinda, i'm gon na learn how to write one sometime. I know how to put a bunch of numbers and put query quarry whatever it is, and it tells me how many hours i can build. That's the only one.

I know how to do it's the important one though right. This is the table that tells us how to select air conditioners, and i'm going to show you single speed, two speed variable volume. What does it say? 115 percent of the calculated gain 120 percent of the calculated gain 130 percent of the calculated gain. What does this mean? Don't oversize by more than 15 percent single speed 20 to speed 30 variable volume.

Is that the third or fourth time i said that today right, you don't have to memorize it, but there are the rules we follow. Do you predominantly put single stage equipment in or something else? Okay? Don't ever let the phrase i oversized it by more than this, but it's okay, because it's two-stage or variable volume come out of your puss. It's not the way it works. You guys do a bunch of the variable stuff right.

Don't exceed that number, if you're going to exceed that number you're putting yourself intentionally in the butt kicking line or you got to go get you know, ancillary dehumidification. That might be the strategy for your rich people's houses, but i'm going to try to avoid it. If i can it's the way it works right, heat pumps follow the same rules with heat pumps. We have two classifications, we got condition a that's a regular house.

We have condition b condition, that's condition, a that's. A normal, sensible heat ratio in the house, something less than 0.9 condition b is going to be a house that has a sensible heat ratio greater than 0.95. That is an expletive tight house being able to get a sensible heat ratio. That high is what's that yeah, it's bill, spone's house call him spoon, he mispronounced my name in a video, and i i'm just beyond livid about it, because i have such an easy last name to pronounce.

I don't understand why people do it, so i'm going to call him spoon from now. So do i i've known him for a for a long time he's a good guy, but anyway there are the few and far between houses that come out at 0.95. If you have a house that has uh is super tight, that's what it is, and your heating degree days, divided by your cooling degree days, come out greater than a two, my market, it's five to one so week bills market would be in. This would similar you can oversize as much as 15, 15.

000 btus. Beyond that, it's a hard stop. Oversizing heat pumps is not recognized in the standard in manual s. Is there guidance in the appendixes if you want to oversize and use ancillary dehumidification yeah, but there has to be something between the ah and the homeowner and i've said.

Ah, i think a couple of times are you down or no idea authority having jurisdiction right? That's code speak for code official, so the code official says i have no idea what you're talking about go ahead. You can do whatever you want, but if, if he's on point and saying i want to see paperwork, i want to see documentation. That's what the the guidance specifically says we'll get to that right. Now: oversizing authority for heat pumps, i'm not going to read it verbatim, but it says you can do it.

If you meet all these requirements and all those requirements, are you got to prove that it's going to work? You have to give some advice on. Should you run the fan all the time right and i'm going to say, that's going to be a hard? No in your market, unless you're conditioning it yeah, but i'm more concerned about the fresh air you're bringing in i want to be able to be sure that it's at you're not adding humidity to the house when you do it so you're going to get one of Those makeup beer units put that condensing unit on it and somebody's going to go on facebook and say look at that idiot installed, but they don't realize that you can add comfort cooling to make a bear. So that's bizarre, but there's a bunch of stuff. Yes, sir.

Oh excellent and i'm going to say yes, sir, every time, because that's just the way it is so that means i have an hour or i have 45 minutes. I might actually run short of slides, i'm going faster than i, oh, no, i'm not i'm not halfway. There yet again, i don't want to go through this verbatim. Simply for the fact: it's not it's in the appendixes, it's not part of the standard, and if this is a strategy that you want to impart, if you can mathematically prove that it's going to work, it doesn't give me heartburn, but don't ever put yourself in the Situation where you haven't talked or spoken to the code official who might bring the pain in the event, he doesn't agree with you, because code is code and if you follow what the guidance in manual s is the oversizing and ancillary dehumidification it's listed.

It's not part of the standard, it's in the appendixes and it has stipulations, and i can say that akka is actively involved in updating some stuff in manual s and i don't think the oversizing stuff is going to become part of the printed standard. It says if you're in a cold climate and your equipment has a latent load on it, in other words you're in a heating dominated climate, but yet you still have to get rid of moisture in the summertime. It's engineered dehumidifier should be part of the system and we have to go through and mathematically prove what's taking place. It maxes out at 85 percent of your latent gain, simple numbers.

10 000 btus is our total gain. 2000 is latent. The house has a 0.8 sensible heat ratio. 85 percent of 2000 is uh.

I can't do that. Math, that's 85 uh, 850 times 2., so that would be the max size of our dehumidifier. I don't know why i had such a hard time converting dehumidification into real btus, but it's a pint is a pound. Dehumidifiers are rated in days per day, not per hour.

So it's well, you do the math. It's a pint is a pound. So it's 60 pints per day. If it's 60 pounds a pound is a thousand btus.

That would be what 60 000 bts a day. So we would divide that and that's how it all works out. That's how you quantify it yeah, something like that. So do the math document it essentially, what they're looking out for is energy efficiency in this part, there's no reason to put the biggest dehumidifier in the house if it's not necessary and i've played around with this over the years.

I'll take the i have a two-story house with a basement. I have a dry basement, but it still needs a little bit of dehumidification for a couple of years there during the summer for a week or three, i would take the dehumidifier from the basement and put it in my master bath and it was kind of ghetto Because it was just draining into the shower in in my human car wash, but you could drop the the rh upstairs easily by five and if the humidity is higher, it's easier to pull moisture out of the air. But if, if i was running, you know mid 50 percent on low low sensible gain, but you know high dew point type days, i could drop it five, six, seven points by letting that thing run for two or three hours. So when you start doing the math behind this, oh, this is pretty cool.

So then, last year, when i was here, i was listening to nikki talk about the dehumidification. I'm like i'm gon na buy one of those dehumidifiers. So when i got home last year, what did i buy? I went on facebook marketplace and what's the best time of the year, to buy a dehumidifier in february, because i got one that was 300 bucks at the walmart, but i got it for 75 bucks. The people only used it for a couple of months.

They were moving it's on my washer and it it drains into the washing machine drain. I have one of those houses where you go up the stairs and there's a washer and dryer at the top of the steps, and i was supposed to move my washer and dryer from the basement up there when we finished our upstairs. But i can't read a tape measure and i made the room too small, so we got a different washer and dryer for that room, so hi brad yeah. We got two washing machines and two dryers, but the truth is, i can't read a tape measure and oh there's, two of us.

You want to hear some cursing. We were trying, they wouldn't fit. You lifted one up over and went like this, and i'm like and he's like. You got to move it over, and it was only like this.

You know when you look at a washing machine and the the white side goes back and you hook your tape measure on it. You measure it's cool. Well, it sticks out like this much further it ain't fit. Oh, i was pissed got ta, remember who's standing up here, man, here's the rationale it's in the appendix this is the way we sum it up.

Performance model modeling maximum. I can't read the stuff verbatim. The best part is the line. However, most practitioners are not positioned to undertake such evaluations.

The marketplace will not absorb the cost of such efforts and most code officials do not have the skill set time and i'm going to add inclination to check these calculations.

11 thoughts on “What is proper system airflow”
  1. Avataaar/Circle Created with python_avatars Nathaniel Crum says:

    So did he get his new job for Acca during lunch? This one he doesn’t have it and the manual D one he does?

  2. Avataaar/Circle Created with python_avatars Brian Mcdermott says:

    Great info. And very educational.

  3. Avataaar/Circle Created with python_avatars CHOMAHOMA says:

    Thank you so much for this video. I need to get a hold of Ed for a couple of questions. I got above 62k BTUH of heating and 24.202 BTUH of cooling. I need to know how to compensate as much as possible for this difference. I got to do a lot of stuff in order to reduce heat loss. The house got a lot of windows. 23 panels in total.
    I need more info on Manual D. If you guys have the class on Manual D, I will appreciate it so much. He said he had more info on heating before jumping into Manual D.
    The work is for my own house and it is my first time doing it.
    Any help is highly and truly helpful and appreciated.

  4. Avataaar/Circle Created with python_avatars smacleod69 says:

    When a company doesn't do a load calculation, How do they know what the sensible and latent heat ratios of the evap coil is? and if the a/c will do the job. I've tried to explain this to my fellow techs and people I work with how important this info is and they don't really care about that stuff or even want to know.

  5. Avataaar/Circle Created with python_avatars Gostevo79 says:

    Very important information, but these videos are getting hard to sit through.

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

    With the length of the video,my A D D was kicking in at various times but in general I've had "pre-covid" classes specifically designed for equipment selection.
    Thanks for the video!
    Stay safe.
    Retired (werk'n) keyboard super tech. Wear your safety glasses.

  7. Avataaar/Circle Created with python_avatars yafiteli says:

    I would love it if you would make a video showing how to measure CFM using basic tools like a hot wire anemometer. There’s many of us who work for small companies or independent operators that have to make do with simple tools.

  8. Avataaar/Circle Created with python_avatars HK HSM says:

    Great information and knowledge.
    Thanks for sharing

  9. Avataaar/Circle Created with python_avatars LOVIN TRUMP says:

    NM lol im blind Are you in Ottawa ?

  10. Avataaar/Circle Created with python_avatars LOVIN TRUMP says:

    where are the links to manuals or address to download them ? Thanks really appreciate the hard work bringing us the vids Service area Kanata??

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

    2 hours I'll have to revisit!🤣

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.