She ate it. My name is Nikki Krueger and I'm the building science manager for thermistor for our residential line and light commercial products. Today, we're going to be talking about really how building codes and our building practices are changing, also how some of our standards are driving. The need for dehumidification, like ventilation and Ron, is going to be jumping in later on, more on the light commercial commercial side and applying dehumidifiers for those applications as well.

So, just a little bit of background, the company is thermistor. We are located in Madison Wisconsin, that's where our factory is where we manufacture our dehumidifiers. We invented whole house ventilating dehumidifiers in the mid 90s there's a gentleman named Ken Goering who invented these he's around 80 years old now and if you ever go on a forum called HVAC talk, he's known as teddy bear on there. He will answer any moisture questions.

You have, and what's great about ken, is his honesty and the capability of our dehumidifiers, and he will probably be the first one to tell you when a dehumidifier is not going to fix a situation, because we really want to make sure when you're, applying a dehumidifier. That it's going to be successful and there's lots of things we need to take into consideration before doing so. So we also invented the first horizontal crawlspace dehumidifiers, which is our Santa Fe brand, so basement and crawlspaces quest. Is our commercial line anybody's working in what we call agriculture dehumidification, so grow houses of any sort we manufacture dehumidifiers for those applications as well.

Phoenix is our restoration line, we're probably one of the largest manufacturers of restoration equipment. So when there's hurricanes or water losses, anything like that and what's important about mentioning, that is a lot of the components used in our commercial dehumidifiers, are used in our residential dehumidifiers. So and that's why we can offer a six year warranty on our on our dehumidifiers. As well so just some basic terms, which I never assume anybody knows anything and I just want to or everything - and I want to make sure that we're all on the same page so sensible load is the temperature.

Obviously, what the thermostat is trying to get to is that sensible load and then the latent load is the moisture and that's really what we want to address with our with the dehumidifiers. So a pints a pound the world around. So if we say a dehumidifier, 70 pints or 70 pounds, it's the same thing. It takes about a thousand BTUs to remove a pint of water which, when we start getting into our tighter constructed homes, we really might have to take in that consideration of the heat from a dehumidifier a little bit more.

And then one CFM in is one CFM out and really, if you're in a humid climate, one CFM out one CFM in and we're really when were using exhaust, only ventilation or that kind of strategy. We really need to think about where we're sucking in that other CFM that we're exhausting so hat goes to cold. Wet goes to dry high, goes to load, so in our mixed humid and hot humid climates. We really need to be thinking about.

Our house is constantly being bombarded with with moisture with heat if we're using exhaust, only ventilation we're gon na be bringing in even more of that so really important to know. Obviously, in the wintertime, if you're in a colder climate, it's the opposite right are our houses. Are like a hot air balloon and everything is, is trying to go out, so relative humidity is relative to the temperature. So, what's really confusing is a lot of our organizations like ASHRAE American Lung building, science Corp.

Everybody is telling us to try to stay in this humidity range, but what's really important is you, you can't stay in that humidity rain without actually understanding what the temperature is as well. So if it's 50 degrees, this amount of water is 85 % as soon as we heat up that air, that amount of water is only 43 percent, so relative humidity, obviously is relative to the temperature. Relative humidity is important when we look at the contents inside of a house, so the carpet, the mattress, the couch. All of that is constantly absorbing that relative humidity inside of the house, and then we get in whoops.

Then we get into dewpoint, which is really important, because when we start seeing condensation on surfaces that very quickly can lead to microbial growth, so dewpoint is very important in our industry. I think more and more we're hearing that we would all like to go more by dew point instead of relative humidity, but homeowners don't understand either one of them really, but they can go out and buy that little relative humidity sensor. So it makes it easier to try to talk in their terms. So if the dew point is above the surface, temp condensation will occur and if you keep it below so closets, always an issue right.

We get a lot of microbial growth in in more humid climates. In closets in corners those kind of areas where we're not getting a lot of air movement and potentially we've got hot air on the outside cold air on the inside and we start hitting dewpoint in those crawl spaces. Anybody here working in crawl spaces, we deal with a lot of condensation issues because we've got water pipes and ductwork crawl spaces is a big one also. So this is a dew point map.

This was actually last October and a lot of times when you're, when you're working with in the dehumidifier business everybody's. Like oh, you know I people in Florida. They need a dehumidifier, it's it's so humid down there and the reality is. Is there are certain times of the year down here of we're not running the air conditioning as much but a lot of times? The air-conditioning in our homes are running quite a bit down here to be able to remove that amount of moisture the last October.

You can see, I mean all the way up into the Midwest and the Northeast. We had some pretty high dew points and most likely we're not running any air conditioning the farther north. You go when the dew points are that high, so dehumidifiers really shine in shoulder seasons and down here in Florida, which could be you know November as a shoulder season down here nighttime when the air conditioning isn't running as much that's when we really want to apply. We want to set up our air conditioners to run to remove as much water as possible.

Let it do its job, but let it get to that temperature setpoint, don't extremely over cool and then let the dehumidifier kick in to get you to that set relative humidity. So this is when we're talking about dewpoint and hitting condensation. This is actually a product project that teddy bear ken Goering drugged me into in Northern Virginia, and these were lead built townhouses, and this is the third floor. Master bedroom and the homeowners are the the townhouse owners actually ended up cutting out the ceiling because of the condensation, and it actually had rotted out the drywall on the ceiling and what happened was as they were, having high moisture, and so they called their HVAC contractor And the first line of defense for the HVAC contractor was to turn down the fan on the AC system, and so he turned down the fan on the AC system to run longer run colder, and this ductwork was wrapped.

It was insulated, but we what we ended up figuring out is you know when they insulate the ductwork and they go to the top. It always isn't sealed perfect around that ductwork. So we had actually they had cut out here in the rim and band and we pulled out the fiberglass batting and you could see it was black. So we knew we had a lot of infiltration coming in to the ceiling cavity and we had hot warm air coming in and it was hitting on that ductwork where it wasn't insulated, perfect and actually, when they removed that insulation.

It was just water coming down. So while we want to set up the air conditioner to remove as much water as possible and to run without over cooling too much, we also have to keep in mind when we're running. Where could air be coming in? We could have a super tight house. We could be less than you know three ACH fifty.

You still have holes somewhere and you don't know always where all those holes are so you've got to be careful when you're when you're running and they were running continuous exhaust ventilation as their ventilation strategy which, if you are in a mixed, humid hot humid climate highly Highly caution against running continuous exhaust ventilation as your ventilation strategy, because you are sucking in every CFM going out you're sucking in from somewhere, and you don't know where you're sucking in from so it's it's not conditioned it's not filtered. So we stopped the the continuous ventilation. We ended up putting in a whole house dehumidifier to also try to keep this ductwork a little bit warmer when the AC was running to prevent this, but we are seeing more and more of a duck were that is condensing with this over cooling strategy. So we have to keep in mind what what potentially could happen when we use that strategy, so Brian or causes the relative humidity.

Did anybody see this article that Brian did it's a really good one causes of indoor relative humidity low heat loads, so the tighter our houses are getting? If you live in a state that is 2015 code or newer, you are in a low load building state. You might not think it is, but it you are building tight houses, so the lot of builders out there say you know: I'm not: building low load homes, I'm just building the code. Well, you are building low load homes if you're in a state Maryland. There's several of them now that are on that 2018, even so, that gives a short run time equipment on our short run times on our equipment, and we also have a lot of system over sizing, naturally by Manuel J Manuel J over sizes, by at least 15 %, typically, we over size beyond that, because we don't want the call backs.

We have a lot of external humidity drivers, a high outside internal people, houses work till you put people in them poor or no spot ventilation. They got to use that ventilation. So we put it in, but you know homeowners actually have to use it. One of the things when I'm talking to homeowners about using their exhaust ventilation in their bathrooms is it needs to run 20 minutes to a half an hour after you're done with your shower.

So you know we go in and we flip it on. We leave the bathroom, we shut it off. We really need longer run times on our exhaust ventilation to get that spot ventilation and those in that area whoops. So our HVAC systems are getting more energy-efficient and to maximize that energy efficiency or having high sensible heat ratios which we'll go into, but basically they're, not removing as much water as they used to in order to be very energy-efficient.

Getting to that thermostat setting not enough dehumidification capacity on our HVAC systems, low space temperature and then again, relying only on the air conditioning system to D humidify again, we want to maximize it, but we can't rely on it to get us to that. Fifty fifty five percent relative humidity setpoint all the time - oh excuse me so for lower humidity home. You want longer run times. That's really hard convinced some homeowners when they bought an energy-efficient house and they've been sold on that, and then you tell them that we're gon na have to slow that fan down and run longer times in order to D humidify.

The whole goal of that energy-efficient home was to very shorter run times. We need a colder evaporator, coil, so again, you're selling, I'm a high efficiency air conditioning system at a high evaporator coil temperature, and then we got ta get that temperature down on it, which is going to cost. You no cost some more energy, less moisture coming in from the outside, we less moisture being generated inside. That's always challenging people aren't going to change their ways, typically higher indoor temps, which, if you use a dehumidifier to control the relative humidity, you should be able to set that thermostat at a higher setting and feel more comfortable, so potential energy savings there.

Extra water removal with a dehumidifier and making sure that they're using that spot ventilation, so people generate moisture about a quarter of a pound per hour. So a family of four is a bike about two pints or pounds of moisture an hour. So we need to make sure that we're taking that into consideration, so we can design for this. We in our manual J's and everything that our equipment sizing we can.

We can design for this. What we can't design for is things like this, so this was about a 400 square foot apartment in out by Virginia Beach in Virginia, and this lady was so excited to show me her QVC clothes drying, hangers, and I think this project had two ton units HVAC Equipment on these units, so when you walked in when it was running, I mean it just blew you over, but it didn't run very long, and so we had a lot of microbial growth in these these apartments. And then we have situations like this. We have whether it's legalized plant growing or illegal plant growing.

We we do get a lot of these situations as well. This is hard to design for and we can't control what people do in their in their homes. So we've mooster balancing - I don't know about two years ago, two summers ago now I know in the mid-atlantic lots of rain lots and lots of rain high humidity buildings that had never had problems before actually hit what we called. You know the dripping point.

It was that tipping point where we just had a lot of buildings, a lot of homes with moisture issues. So you know it's really important that are we tried to keep our houses balanced. You know they can absorb so much moisture, but there's going to come a point that if we don't address it correctly, that we're gon na have that problem. So I've got this video where your wet dry, what what, what and then we've lost you know.

We've lost the battle at that point, so so low, sensible load buildings has anybody heard of the new akka manual llh, no okay, yep, so echos recognized that basically our houses are getting tighter. Our building construction construction practices are changing. I was a member of the committee that helped on this, and basically it's it's a guide that, if you already are using manual Jay Manuel s, manual D, that this is a guide on how to size in what equipment you should be using based on climate zone. To size, equipment for these tighter houses, so it's it's a guide.

It's not meant to replace any of those, and basically it says in this write this guide. If you're building in an estate, that's 2015 IRC code or or new or you're, building a low load, home and low load, basically it's all it's it's low, sensible! That's why I kind of have a problem with the title of this, but it's low sensible, not low latent. So we have continuous insulation, which is low, cooling load, airtight construction, which is driving down our cooling loads, optimized windows and shading. Mechanical ventilation is actually adding to our sensible and our latent.

Potentially here it says, ducts and conditions. Faison's is obviously driving down our cooling load. It's said that doesn't affect the latent load, but I would argue that it would actually be driving up our latent load, because when you put ducts and conditioned spaces, our AC isn't going to run as long and remove the moisture that it used to. You know ducts when most of them were at 30 %.

You lost 30 % of your cooling and heating through through the duct, so now you're keeping it in a conditioned space, which means less runtime on the AC, which means less water removal as well. So basically, this manual is saying that, if you're designing for these low load homes or newer code built homes you're starting at about 1500, a ton per 1,500 square feet which is really going to be hard for a lot of us in the industry to design to Comfortably and and understand that, but it's where our homes are going and there's a lot of challenges when you start designing for homes at you know a ton per 1,500 square feet, we got to think about air distribution and not having stagnant air. We have to think about air filtration ventilation throughout that entire homes. There's a lot of challenges that come in when we start building to these tighter homes.

So there's a lot of organs and organizations out there if you're, not just building to code but you're. Building to these tighter homes that have a lot of programs that basically want us all, no matter what that program is, everybody wants to be more energy-efficient. We want less runtime on our HVAC equipment, that's the goal, but there's a lot of challenges. Obviously that come with that one of the things that we typically use and was higher seer equipment and we'll go over to you know why, how that higher seer equipment is actually causing us some more moisture issues as well.

We have a lot of partial load and no load times even here in Florida. There's a lot of homes that are seeing mostly partial load run times, even in peak season, because they're beings built so energy efficient and more efficient, sensible cooling at the expense of Layton removal. So I don't know in in your areas. I know everybody's from kind of all over the place, but I know like the ng BS has a program for for green building and even Energy Star Net Zero is a big one.

That's coming down the pike where you need to look at the indoor AirPlus program, but most of these standards in them have the criteria to put in equipment HVAC equipment that will keep it at sixty percent, relative humidity or dedicated dehumidification. And what they're coming to us? Now indoor AirPlus has come to us and said you know: maybe this using the HVAC equipment to keep us at sixty percent. Isn't always the right solution all the time, because what we're doing is over cooling to try to keep us at that which again, we've saw some condensation and when we have comfort complaints when that happens as well. So maybe we should be recommending more dedicated dehumidification in certain climate zones, so low loads, Barry but sensible loads very, but latent loads.

Pretty much stayed the same. This is some data logging we did in Texas. I think it was in the Houston area and, as you can see here, this is our outdoor temperature. So you know morning we're at about seventy four degrees.

This is our outdoor relative humidity, and so obviously this varies from 70 % to when we heat up and middle of the day. But what's not changing is our dew point. Our dew point is still saying the same throughout the day, regardless of what the temperature is, and this is why we say we really need to focus more on what those dew points are then focusing on the relative humidity. So we can have, you know 90 percent to near zero, sensible loads in one day, but the moisture is still saying the same, and this is our ventilation there.

This is what we're we're bringing into our home and why we need to really think about controlling humidity. All day, and not just when our ACS running at peak load or partial load, so there's the need for dehumidification is is significant. Of course, we've got. Health house is a big one and becoming more and more we're seeing that a lot of homeowners automatically think when they buy a newer home that it's going to be energy-efficient.

But what? What we're seeing from statistics? I - and I have a slide in here as homeowners - want a healthy home, so a lot of builders are going to marketing healthy homes instead of just an energy-efficient home and all these organizations again everybody's got this range of relative humidity by not really talking about temperatures. So if you go to our website, we actually have a link to this old house segment. Ask this old house - and we did a segment in New Orleans in July, and I was down there for most of the shoot, except for the very end I had to leave and of course that's when they talked about the controller and where to set the relative Humidity, and so I'm watching this segment and as it's airing and the homeowner is like well, what should I, you know suck that at and Richard who is, I think, from Minnesota or somewhere up north coast. I like to keep it at 35 percent and I went oh I mean if you can get to 35 percent in the winter and a northern climate you're happy right.

I mean that's like you're comfortable, but to try to get that in New Orleans in July. I'm like oh, it's just gon na run all of it, so I had to talk to what the homeowner and said well, let's, let's aim for 55 % and I think you'll be pretty happy with that. But again, that's the problem with this. Relative humidity is as homeowners.

You know. I saw something that I need to have 50 % and they think they need to have 50 % all year and depending what climate zone you're and that's that's not true. We need to know the temperatures. So here's what ashtray puts out there for the health - and this is really important and I'm sure, you've seen this everybody's using it.

But we really want to try to keep in this optimum zone of relative humidity and a lot of this, especially when we look at chemicals and a lot of people are having more and more immune deficiencies and chemical sensitivities. And it is proven that the higher the relative humidity, the faster our products in our home off gas. So if you can keep the relative humidity around 50 to 55 percent, they off gas slower and typically will help minimize that ken teddy bear was involved when the Chinese drywall was going on down here in Florida, and what we figured out was that the higher the Relative humidity, the more off-gassing we got from the drywall, so they actually know that the drywall went up north, but it's harder to find because we don't have the relative humidity for as long as period of time as down here in Florida. Unfortunately, a lot of homeowners, of course we're not I mean even as a mother, I would not accept well.

If we put in a dehumidifier, you won't get the off gassing from the drywall. I mean at that point. People were like just get that stuff. Out of my house, but we didn't know, you know that was one of the things that we figured out is even formaldehyde if you control the relative humidity that usually minimizes a lot of the família hide levels as well and here's one of those statistics we talked About with healthier homes that homeowners are willing to pay more for a healthier and actually builders and some of the data that supports us as well as they sell faster when they promote that the home is healthy.

So here is our manual J using the manual s calculator, and this is industry, best practices right now right, so we're using our May and we're running our manual J's we're picking equipment using our manual s. So this is again Houston. We have an indoor cooling design of 78, which is high. That's that probably should be a little bit lower.

Our outdoor cooling, temp at peak is going to be 93 degrees and we're aiming for 50 % relative humidity, so manual J is always trying to get you to that 50 percent relative humidity level. Typically, so, we've got four people in the house. We've got a CFM of fresh air of 71 and this is going to give us our total cooling load with the sensible being 29 and the latent being 71. We know more and more with our building practices that these numbers are not that drastically different, that we're actually moving closer to our sensible and latent loads being closer to the same number.

But I just took the the acumen akka manual GE class a couple months ago, and there was a lot of talk still of oversize, because you don't want that call back in July when they and we got to be very, very careful with our over sizing. If, with our new construction practices, we really do want to right-size as much as possible, depending on your homeowner, and you know, you might even want to undersized a little but that's really hard, because we don't want those callbacks. But the reality is. We need that that AC to run well, the the software does it automatically 15 %, which most people don't know, and then a lot of contractors then add another 15 %.

So I mean we could be 30 to 40 % oversized. So if you really just go with what the software gives, you you're automatically 15 % oversized, and that's when you I mean these calculations are peak load. Do you know how often our houses run at peak load? What percentage of the time 1 % 1 % of the time we're running at peak lows and that's what we're designing for so that's where we have to be really careful, then really over sizing, and I mean we're just not going to get the Layton removal. We we should be getting from our air conditioners, I mean it's all.

You've got that piece of equipment is already in there. We want to maximize that, but we also know that it's just trying to get to that temp and you can have an RH on it. But again you know you set it to that RH, it's just gon na over cool, and so it's challenging it's. It's very challenging and we're going to talk about some of these other ways to G humidify using other equipment.

So again, the air conditioner is just trying to get to that temperature setting most of the time 70 and rainy not gon na happen. I mean they're, not gon na run it. That's that's our days when we have the most challenge with humidity. Is that 70 in rating? So this is from ASHRAE.

Typically, before you get effective dehumidification, you need at least 14 minutes of run time before water starts going down the drain, a friend of ours, that is, a building building scientists he monitored. I don't remember how many multifamily apartment units I think it was in Tennessee. Two summers ago and the average runtime was seven minutes on the on those systems, because they're so oversized especial for multifamily, so variable speed slows the air-conditioner fan down like we talked, makes small smaller amount of cold air. This is a register that was here in Florida.

We start getting condensation on registers when we get that really cold air and again you know, one speed of variable is off so seventy and raining the homeowners walking by they're feeling cold air coming out of a register they're most likely gon na shut it off. Ductless mini-split great technology does a really good job of conditioning small spaces very quickly. Dehumidification mode is typically a timer based system, so you're gon na hit d hue mode, and then it's gon na run for a period of time based on a timer. You can get into a lot of trouble very quickly if you're using that mode.

That's we have a great partnership with Mitsubishi. We do a lot of their builder trainings together. They do not encourage their builders and contractors to count on that dehumidification mode, especially in higher performance homes in buildings, because you will get in trouble with that. Have you ever seen a condensate line on a ductless mini-split? It's about the size of a pencil, not a lot of water, going down those all right, so high energy or high seer AC systems.

They have larger coils on these systems, so they're, very efficient at getting to that cool temperature or that that setpoint and the thermostat these coils hold about a pint or a pound of moisture on the coils. So if you per ton sleep, a five-ton system, you've got five pounds or pints of water on the on the coils. They don't get as cold as the older AC system. So a little less water removal going down the drain and they get a higher seer number by running the fan, once the compression compressor shuts off so you're in Arizona, and you want evaporative cooling.

This is a good strategy. If you're in Florida, you probably don't want all that water, that's that's potentially five pints or pounds of water. That's on that coil! You don't want that riah vac into your house, and it can increase the relative humidity back up to by about ten percent. If we do that, so there is an option on those systems not to run the fan.

Please suck that up if you're in a hot humid climate or a humid climate, but you lose some of that energy efficiency that you were sold or you're selling your homeowner as well. But it's not much, but please please please be aware of this, because it has led to definitely some issues so the sensible heat ratio is this: the dehumidification effectiveness of the air conditioning. So, basically, how effective is that piece of equipment at removing water really really need to to be looking at this? More and more, when you're picking your equipment is what is that sensible heat ratio of the of the equipment so what's interesting about? This is typically the higher the sensible are, this year, the higher the sensible heat ratio. So this 33 seer system is that 0.96.

You really want to be at about point. Seven, four, I think, is what ASHRAE 0.77 or lower in order to get the maximum water removal that system right there isn't removing much water at all, which is fine. Just you know, choose it. If that's, what the homeowner is really after what the understanding that you're, probably going to have to have some sort of dedicated dehumidification, those are all ductless units, those are Mitsubishi, yep, Mitsubishi numbers, so we're gon na.

This looks like a lot here, but I'm gon na break it down for you, one of our colleagues built on very energy-efficient house in Raleigh North Carolina and he's using ductless a lot of people in here using ductless, some not a whole lot. Okay, some caution when doing so so the the orange here is our latent. The blue is the sensible and then the gray is the total cooling. So we're gon na break this down this little section right here, and this is what it looks like when we break that down so from.

Let's take this right here, we've got 10 p.m. see. How much do we have here? We've got about a 20 with a 5 minute runtime there. Yes, we've got 10 10.

We've got a 4 minute runtime here on this ductless heat pump performance. So, with 4 minutes of runtime we're getting a sensible heat race or a sensible heat ratio of 1.5, which is not even really possible and the reason that we get that on here, as you can see, we are sensible and are late and they're. Almost the same is because when it shuts off and that coils loaded, we have no water going down the drain in 4 or 5 minutes of runtime. So all that water on the coil is actually going back into the house, so we're getting cooling with humidification when we have those short run times, so we've got to get our equipment running longer periods of time.

In order to get more of we'll look at some data here, more something looking like this, where I think we have 12 29, we have almost 45 minutes of run time on this on this ductless heat pump in the middle of day, which gives us whoops the Sensible heat ratio of 0.65 so we're getting really good water removal. We really need those a lot longer run time. So, even if you, you know, you know, it doesn't have to be ductless to not be removing the water we need. If we have a tight house in an oversize system, we have the same thing going on we're not getting the long run times.

We need for that for that to go down the drain Charlotte North Carolina, I've got we've got data pulled for all over the country. If you're interested after I go through this and explain it a little bit more that we can help you, so this is an 1,800 square foot house with four people in it built to code in Charlotte North Carolina, and what we did is there's a software program Out there that's free, called B opt, I think, NREL offers it and you can go in and put in different housing and scenarios and in different equipment to get data. That looks like this. So this red line here is a 14 seer system.

Blue line, the lighter blue or darker blue is a 14 seer with a 70 pint dehumidifier, the yellow is an 18 seer. The lighter blue is 18 seer, with a 70 pint dehumidifier and then the red is a 22 seer system so from January. So, basically January through February - and this is our indoor relative humidity and what you can see by using the different systems - is kind of out of out of range or high you're going to be, if you're, counting on those systems to control your relative humidity alone. So, if we're using a dehumidifier - and we set it at 55, 55 percent relative humidity, with even a 14 basic 14 seer system, we're gon na - have better control and probably better comfort in that house.

Then, if we were trying to use 22 variable speed system to try to control that relative humidity, because no matter even using variable speed, you have to have a load in order to remove that water and if there's no load, no sensible load, it's not going to Run what you need it to in order to remove the humidity? Does that make sense? So we have these four all over the country, if anybody's interested in actually one for their region to supply that, for you and walk through it more. If you want so a whole house, ventilating dehumidifier is ducted with the HVAC system. You can bring in outdoor air to get supply ventilation. Ours has a merv 13 filter.

So if you're in California, you're meeting your ventilation standard or code and wedi humidify, the entire home separate from the AC system, we're gon na utilize, the ductwork, but hopefully the most energy-efficient way that you can set this up. I mean there's other ways to do it, but the most energy-efficient way is a dedicated return to the D hue, and then we tap into the supply and we're only running the dehumidifier. When the AC has come on, shut off and hasn't met that relative humidity and we'll go into some install options as well, um, I'm not going to go into that one. So it is supply ventilation in a hot or in a humid climate.

The building science experts agree that we should have try to have a slight positive pressure on the house to try to stop that infiltration, because when it's hot and humid everything's trying to get in our house through every crack and crevice that we do a slight positive. Now you can use an ERV and adjust those a little bit to put in more of a positive with the understanding and ERV will always contribute to the moisture load. It'll lessen it but it'll always contribute to it, and I've got some data to show that the air can be filtered again. Slight positive pressure we mix with the air in the supply, so if it's 30 degrees outside and we're just bringing in fresh air through the dehumidifier, we're not dumping 30 degree air into the house.

We're mixing that in the box and through the ductwork before it comes out and there it really it's fairly doable as long as you got the room for a dehumidifier in a retrofit situation, most of our dehumidifiers always go in for retro cuz. We're is there to fix a problem. Builders have gotten into some problems and they're, realizing more and more that it's easier to put a dehumidifier in at the time of construction and not have to deal with warranty issues remediation that sort of thing it's much cheaper to do it on the front end than On on the back end, but almost all of our stuff traditionally has been retrofit applications, so this is when we are talking about using an ERV anybody using a rvs now, okay, so typically in a humid climate, a lot of times, the RVs are used colder climates H, RVs are used, but the energy, the ERV will exchange some of that moisture in the coat in the core. So if it's humid outside and drier inside, we'll bring in less so if the air-conditioning is running and we're removing water and it's drier inside.

But it's high dew points outside will exchange that moisture in the core and will lessen the load, but we're still always going to contribute to that load. So this is a taste study we did in Orlando thinking. It was about five or six years ago, with the nhb. The International Builders show had their big show here, and this was their show home.

The homeowners wanted to put in our dehumidifiers, but the equipment manufacturer who spends a lot of money with the nhb said. No we're putting in an ERV, so we worked with the the homeowner and as soon as I got the keys back to the house after the show home we monitored the ERV and what we. What you can see here is the blue line. Is the the relative humidity inside the family room and the Green Line is the dew point.

So basically, the relative humidity, which was you know above 60 %, was following the dupe outside, so we took out the ERV. We brought in their outdoor air with the ventilating dehumidifier and we set it up fifty five percent. We don't care what the dew point is outside we're just going to control the relative humidity inside the home. So this was a spray foam home.

I you can get tight homes without using spray foam, but again the tighter our houses get the more important it is that we're controlling that relative humidity, outside of counting on our air conditioner runtime. To do that - and we have this case study down on our table down there if anybody wants a copy and it's also on our website as well. This was a study that the do do. We did Armen Ruud if you've ever heard of him he's kind of a moisture icon in the in the building science industry.

But basically he just said that if it's humid outside and it's humid in the house, you're not going to get any exchange with that. The ERV for the latent I'm gon na summarize this without going through it, but I'm just put it all out here so ventilating dehumidifier I've actually had some conversations already today. People automatically think that we're going to dehumanize the fresh air we're bringing in because that's what we do in commercial applications a lot of the time with the DOE. As is we try to remove as much of that moisture as possible before we introduce it to the building? The reality is in residential applications.

That would be very energy intensive to do for a small amount of fresh air, so we can bring in outdoor air fresh air through the dehumidifier if the compressor is running because we're removing moisture from the house, because the relative humidity in the house has gotten above Fifty fifty five percent will remove a little bit of that moisture that we're bringing in from that outdoor air about 20 percent. If the dehumidifier is not running and it's time to bring in outdoor air, based on our ventilation, strategy or yeah strategy, we'll bring in the air and then if that makes the relative humidity in the house, go above the set point for the dehumidifier, then we'll bring On the compressor for the dehumidifier, there are some companies out there that do sell, dedicated dehumidifiers for fresh air, so you're bringing in 150 160 CFM about door air. Just like an air conditioner we've got to load those coils before any of that moisture is going down. The drain plus we're generating heat to remove that moisture and putting that heat into the return of the AC system.

And when we do that, we reduce the effectiveness of the latent removal from our air conditioner, because we're heating up the coils of our AC system. So and that's into one of our install strategies that we'll talk about not to do as well. But does that make sense? So it's hard because everybody's like oh, I don't leading dehumidifier you're gon na remove you know all the moisture from our humid outside and that's that's not the way that we look at it. We really care about the relative humidity inside the house.

Sometimes you know it might be a little bit too dry and it's in its human a little bit more humid out. So we might want a little bit of that moisture outside all right. Well, so here's our full line, you you, you have a size house, we have an application for it. This is our recommended install for a dehumidifier.

We like to have a dedicated return, if possible, to the dehumidifier. Then we tie in to the supply of the HVAC system ductwork, and then we all of our dehumidifiers have a dedicated fresh air duct, except for our smallest 70 pint unit, because it's so small you have to tie into the return duct to bring in fresh air. You don't have to use it if you're using an ERV to bring in your fresh air, and you just want to dedicate it humidifier for the rest of the house. You don't have to use the fresh air on this system and the reason we recommend this install is the most energy-efficient way to run a dehumidifier because we're not utilizing fan on the air handler or the HVAC system at all when we install it this way.

If we were to do a dedicated pull from the return which you can, we have other installs on our website, if you were to pull from the return of the HVAC system and then go into the supply, would either have to call it have a check damper In here, or we would have to run the fan on the HVAC system, so we're not just circulating air right here, so either I've thrown the fan or a chuck damper, and I don't I hardly anybody uses a chuck damper in an application. They just run the fan, which is okay to do as well, but again, you're you're running the largest fan in the house when this already has a fan in it, so right here, yep when the air handlers on your handlers operating. So if this is running, we're not getting any air this way back going backwards. Oh oh yeah! Not if you locked it out, no yeah, yeah, yeah, yeah and we're, and hopefully we're not running continuous fan because we're evaporating.

You know, in theory about evaporated all that water off the the air handler. If we were in continuous fan and if you're going to have longer run times and you're still concerned about hitting that relative humidity, you can run the dehumidifier and the air conditioner at the same time too, and that's an option on our controller. You can lock it out from that happening, but I will say in the industry most of the time that doesn't happen if the relative humidity goes above, the setpoint and the air conditioners running they'll just run the dehumidifier at the same time too. So if you're running at a really low CFM together, that makes sense yep yep, so there's yeah, that's true, depending if you're at a static pressure of 0.5 or higher, we recommend not installing the dehumidifiers, so we at least we start having concerns that.

That's that that static, our engineering department and our applicant, I mean, if you have a situation, that you have a question about again. We invented these we've been in the industry longer than anybody, even if you're using somebody else which happens a lot. We get calls to help with with installs all the time. So just let us know we'll give you cards, oh sure, about 20 degrees, difference so from the from the incoming to the outgoing.

So that's why we got to make sure on this supply we get. You know probably what 5 to 10 feet of mixing in there before our first drop, and you got just because we don't want to you know all over the easy chair in the living room. We don't want that that going in so we need some some some room to mix that air cuz. This is so our 70 point units 150 CFM.

I mean it's not a lot of CFM of heated air, but there is heated air. Oh you can yeah absolutely. If somebody's sensitive to that, but I will say that usually, if there's Sun, if we get a call, a complain about it and we fix that - usually it's not a problem all right! So, let's see, if I can get this - oh, oh there, we go to run here. So just an illustration dedicated return to the dehumidifier.

We got a fan inside we can bring in that outdoor air. This is our Lark one of our larger units that features a heat exchanger inside which allows us to pre cool the incoming air to get to dewpoint faster. So if you need a larger dehumidifier and you're worried about the energy efficiency or the energy use usage, these unions are probably a good solution, because we are the most energy efficient dehumidifiers on the market, and then we just use the the supply of the ductwork. All right so no existing ductwork if you're using ductless mini-split s -- one of the challenges of using ductless mini-split siz, trying to figure out your ventilation strategy, your air filtration, as well as getting air mixing and distribution throughout the home.

So we work with a lot of ductless mini-split swear. Yes, now we're gon na have some ductwork in the house, but it's going to be minimized, dedicated return and then off that supply. We typically recommend three. That's again because of the heat we don't want to dump it all into one area.

We want to spread out where we're putting that and typically those will, those supplies will go into rooms that have the ductless mini-split heads. So we make sure that we are. You know cooling that air a little bit as well good, all right return to return anybody using personal is anybody using dehumidifiers anybody do in return to return. Okay, so Florida, Solar Energy, a year and a half ago, came out with a new study on the best way to install a dehumidifier and actually, as a result of that, they do not recommend return to return installs any longer.

We have it as one of our installs because in all honesty for our service department, it is the easiest way to install the humidifier and retrofit applications. There's a lot of challenges where you can't get to that supply. So return to the return has been one, but in our experience I've taken the calls I put in your dehumidifier two weeks ago and the relative humidity has actually gone up in the house and when it comes down to, as they typically did, return to return. Install and the the challenge is, is the same as we talked about using a dehumidifier is dedicated ventilation.

We were heating up the the air, that's going into the AC system, so we're heating the coils of that AC system. So it's not removing as much water as it used to, and it's also very energy intensive to do it that way and when the AC system shuts off and it's loaded and the dehumidifier comes on, we end up reading that air back into the home. So it can be done successfully, there's a lot of cautions in doing it, but if possible, try not to do a return to return install. If it's an option, we have a free app on your phone that you can download.

Basically, what it allows us to do is to calculate how much moisture removal we're going to need based on ventilation alone. So if you're in a state or you're working with a builder or you're, now required to do some sort of mechanical ventilation, this will help you calculate how much moisture removal alone you're going to need just based on the ventilation. So the inlet is what the temperature and conditions are outside. The outlet is what we want inside the house and the flow is the CFM or what our ventilation rate is, and that's going to give you how many pints a day of water removal you need.

If you want to switch it from pints a day to pounds an hour, you just click on that little I and you can switch that you can also switch dew point to grains. So if anybody works in grain, you can switch it to greens as well. So, just as an illustration, you know, we've got a ridiculously high 83 degree. Dew point 85 degrees outside I want 75 50 inside and bringing in a hundred CFM of outdoor air.

I'm gon na need about a hundred and eighty pints of water removal at peak load condition I mean, depending on the size of your HVAC system, it'll, probably keep up with this. The other thing you need to add into this, then, would be how many people are in the house, so family of four 2 pounds of Pines an hour at their home all day. You would have to add about 48 pints or pounds to that, but again we're running at peak load. At this condition.

The challenge we get into is the no load and partial load days 70 and raining and 70 and a hundred percent RH outside I want 70 and 50 inside I'm bringing in a hundred CFM. I've got 91 pints plus another 48 for the people. You know this could go depending on where you are. This could be a week in fall in a lot of locations where you've got some pretty uncomfortable homeowners and potential for microbial growth.

At this point, so here's a situation how we doing on time. Okay, because still dehumidifiers aren't mainstream yet right, so usually we're called in to fix a problem or we've got homeowners that have something that's a little more unusual. This is a very recent call. I got 1,500 square foot townhouse in Maryland, and the wife has an immune deficiency hypersensitive and because they're in a townhouse, the engineer tried to design their ventilation system.

She put as much positive pressure in their unit to stop the infiltration from from the site. They did. Do a lot of air sealing, which is always my first question and then, but in order to accommodate the extra load from the ventilation they upsize the HVAC equipment as well, and then they put in our xt 105, which is the most energy-efficient dehumidifier on the market. To help bring in ventilation so they couldn't use us strictly for ventilation.

They were also using a supply ventilation fan to try to get to this 300 CFM and side and they installed it return to return the dehumidifier. So I ran the calculations and based it worst-case scenario: dewpoints in Maryland, 74, our stubby degree dew point they're gon na some days are going to need 300 pints of water removal a day based on on that and because they up sizes the AC system to deal With the heat load, they also weren't getting as long as run times on that AC system to remove as much water as possible, 105 pint dehumidifier - and this is one thing to to - and we're gon na go into this a little bit too, is all the humidifiers Until just recently are rated at 80 degrees in the 60 percent relative humidity, which is basically an indoor pool, so we don't control that that is what Energy Star rates our dehumidifiers add. It's not realistic. They recently just changed it to whole house dehumidifiers at 75 and 60 and then basement crawlspace dehumidifiers at 65.

60. All of our numbers are going to look a lot worse, but what it's reality and it's a level playing field? We try to be as honest as possible, especially because we worked a lot of engineers, but we didn't want to publish those numbers because our competitors didn't publish those numbers and we don't look as good on paper. But now it's a level playing field. But if you called us - and you wanted the actual specs which will be supplying these on our on our spec sheets now, what you want to look at is okay.

We have 70 degrees in the sixty percent relative humidity on a 105 pint unit, we're getting seventy six pints in reality that because it was rated at 60 and that was 105 pints, but the reality for the more realistic applications. Are these numbers so they're using a hundred? They need 300 pints of water removal they're using a 105 pint dehumidifier and they're getting 76 pints of water removal + they haven't returned to return, install, which you know we're ryu mid affine, some of that air off their AC system. This is our 205 pint. We make the largest residential, dehumidifier, duct and dehumidifier, even this one they're only getting 156 pints of water removal.

So our first strategy right now is because they are adamant and I and I still trying to get where they were. They get the three hundred CFM. Where is that coming from who decided that that was going to make her healthy? I don't know, but we're gon na get the the current unit. They have the 105 set up, return to supply and see if that will help us a little bit and I think we're just gon na, I told them.

They're gon na have to go to this unit. If they're gon na continue to do that - and I wouldn't even be confident that this unit would do it in Maryland, with a 70 degree dew point most of the summer, so we have a lot of challenging situations out there. A dehumidifier will help though it might not. I mean we they might have to go to a commercial application or get out of a townhouse, so they're not so worried about what their neighbors are doing.

So, but again, if you guys ever have those challenging app. You know applications reach out to us and we'll help all we can and obviously be very honest and realistic about what a dehumidifier can do, because we wanted to be successful. I might so they must have did a blower door right to see how much their infiltration they were still getting because they didn't do it, go in and do air sealing, so they must have done a blower door said: ok, we're still getting this amount of infiltration. So if we do 300, maybe that will stop it.

Yeah yeah I mean I don't know it's got, ta be high yeah. I don't know s d12. Just go over a couple unique units. We have a split dehumidifiers.

So if you are sensitive to the heat from a dehumidifier, we put the compressor outside so you'll get first stage cooling as a byproduct of dehumidification, so very unique unit. We've got specs down there. If anybody wants any more, it's a biggie, it's a hundred and eighty pints of dehumidification or 84 pints of dehumidification commercial kitchens, great great application, you're gon na allow dehumidification with first stage cooling as part of it a lot of additions. We see this going on as well a lot of homes that need that want dedicated dehumidification and might just need a little bit more cooling in wall dehumidifier.

We have this down at our table newer product for us last couple of years. Anybody working in multifamily applications where you don't have room for a ducted dehumidifier. You can put this in the wall basements and also like storage rooms, where you need to try to keep some relative humidity. That's what it looks like this is a passive house in Dallas Texas, where they used all ductless mini-split s --, and then they just ducted that into the plumbing of the bathroom, because their building code allowed them to do that and plugged it in cautions.

Here. We just want to make sure that when we do this, we're not discharging that warm air right on this was about a 200 unit project in the DC area, so we just had to move that thermostat. This is a hallway on the other side of the wall.