15 Feb Efficiency And Home Comfort Issues For Custom And Luxury Homes
Wondering why your old Louisville home has chilly drafts and cold pockets, or how to build a truly energy-efficient home from the ground up? For the answers, we’ve invited Eric George, a certified weatherization/insulation specialist from Building Performance Group to join our podcast to discuss a few items that can directly affect your home comfort issues, even on new construction.
Everybody assumes they’re getting the most energy efficient product simply because they’re building brand new, but there are many choices to make along the way that affect the final comfort and performance of the home. Eric often finds there are trade-offs between top-of-the-line efficiency and price, or between aesthetics and comfort.
Top 5 Home Comfort Issues
- Fireplaces: Wood-burning fireplaces require fresh air coming in through a chimney, air cycler or ERV to prevent the fire from burning up all the oxygen in the home. All the holes in the envelope of the home diminishes the efficiency. Ideally, a natural gas insert or electric fireplace will be installed instead, which provides the cozy aesthetic without all the drafts of traditional, wood-burning hearths.
- Knee Walls: Often, 3-foot-high knee walls are the only thing separating the 70-75 degree home from the sweltering 120-130 degree temperatures in the adjacent attic in the summer, so these walls require added insulation. Often, framers use fiberglass or cellulose insulation without OSB sheathing or zip walls facing the attic, which allows hot or cold to pass through. Ideally, builders will install a foam board with insulated sheathing along with spray foam, fiberglass, or cellulose insulation. It may cost more to set up, but it greatly increases the comfort of the home and the homeowner saves money on utility bills and by needing a smaller HVAC system.
- Vaulted/Tray Ceilings: These cool architectural features require greater insulation, since they are close to the roof deck. The building code may only require R19 or R25 insulation in the rafters, but a vaulted ceiling may require R30, along with five inches of closed cell spray foam or 10 inches of fiberglass. Though you can technically pack more fiberglass into a space, spray foam or dense-packed cellulose uses less material and works nearly as well. Another home comfort consideration is to include flush-mount LED lights rather than recessed lights, so they don’t gobble up space that could otherwise be insulated.
- Duct Work: One of the biggest problems in the building industry is the sale of “really fancy, expensive boxes” – the 98% efficient gas furnaces with dual fuel systems and heat pumps – but attaching it to a duct system that is incapable of moving the air through the house efficiently. It’s like putting a Ferrari engine into a Ford Escort. Using building cavities and not fully ducting the system is another common issue. The best method is to use duct work for the returns, which goes all the way back to the architect leaving enough space for proper HVAC design. Lastly, you’ll want that duct work sealed properly to prevent leaks all down the line. Plan for about 400 cubic feet of air per ton of air conditioning, and put flow hoods overtop the supply registers to assess duct pressure when testing.
- Basements: The ground is naturally about 55 degrees year-round. Most people don’t realize, but concrete has an R1 insulation value – about the same as a single pane of glass. Rather than putting fiberglass insulation in the wall cavities just an inch or two off the concrete and going down the two feet the Kentucky building code requires, it is recommended that the top four feet or the entire foundation wall be insulated using a foam board product or direct spray foam application. Insulated Concrete Forms are the gold standard, as are radiant-heated floors (which run a hot water system beneath the home that keeps the entire basement warm.)
Have more questions about your home comfort levels or the energy efficiency for your Louisville Custom Home? Visit www.ArtisanSignatureHomes.com, where you know that we hire a third party verifier to double-check all our work to ensure we meet the highest industry standards of efficiency, performance and home comfort.
Home Comfort Podcast Transcript
Hey there everyone. Welcome to another episode of the Custom Home Builder podcast with Jason Black, the president and owner of Artisan Signature Homes, Louisville’s best known and most accomplished custom and luxury home builder. Jason, good to see you…
Jason: Greg, good morning. Good to see you, and quite the intro… I feel so special.
Greg: You might have heard just there, we have a third guest, or another guest, with us. Eric George with Building Performance is joining us. Eric, good to see you again.
Eric: Good to see you too, Greg. Thanks.
Greg: I think you brought … Well in case people don’t remember you were on the podcast maybe a year or so ago talking about how to make a home more energy efficient, more comfortable. Is that correct?
Eric: I think it was less than a year, but yeah.
Greg: You brought maybe a Top 10 list with you. We always like top 10 lists.
Eric: Yeah, I brought a top 10 list in no particular order that will top 10 home comfort issues that we find in new houses, or things that cause comfort problems.
Greg: Go ahead.
Jason: No, I was going to say everybody thinks that you’re building a new house these days, you’re using the great insulation, and new technology, my house is going to be energy efficient just because it’s a new house, and that’s completely false. That’s one of the main reasons that we hire Eric with his company. He works as an independent contractor, a third-party verification to just verify when we build a home that it’s up to his standards. One of the reasons we wanted to bring Eric is just share with the listeners, if you’re building a house, and you’re not building with Artisan, or even if you are building with Artisan, here’s some things to really pay attention for as you go through your building process. Eric, let’s toss it to you and give us number one.
Eric: All right, so number one on the list, and like I said this is no particular order, but fireplaces. I’ll just say a few things about fireplaces. One, if you’re going to build a new home and you want it to be a high performance home, what I consider something that’s energy efficient and comfortable throughout, then I would recommend that you consider maybe not installing the traditional types of fireplaces that take wood and stuff like that because each one of those fireplaces requires a flue. When that flue goes up and out of the house it usually takes a lot of air with it.
Fireplaces are a really inefficient way to heat your house. It’s a great aesthetic look, people love to have that hearth and mantle in the living area, and it’s a nice thing to gather around, but as far as actually heating your house and keeping it comfortable, I would consider maybe a natural gas insert, or even the newer electric fireplaces that give you that look but maybe not all the draftiness of an older one.
Jason: Yeah, because you think about this efficient building envelope that you’re going to build. Say you do an all foam house and you’re super efficient, but you’re putting anywhere from an eight inch, to some of these bigger gas fireplaces or wood burning fireplaces we do, we have to have an eighteen inch flue that goes through the building envelope. Really, there’s a lot of points in that flue that insulation cannot touch that, so you’re just creating this gigantic hole in the envelope.
Eric: Yeah, and I’ve seen several houses that, they’re very large custom homes and they take the time to insulate them really well, but then there’s like four or five fireplaces in the house, and it’s really difficult and challenging to do those right, and keep the envelope correct. Fireplaces are definitely an issue, and whether they’re natural wood burning fireplace, or a natural gas fireplace.
Jason: Well and one of the tough things to look at too is you think about a fireplace, a lot of times it gets installed in a house prior to installation. I know a lot of times the insulator comes in and is like, “Man, that’s a great fireplace and all, but how do I insulate behind it?”
Eric: Yeah. It’s on an exterior wall it can be really challenging. You got to make sure that you get your insulation guy in there before the fireplace ever gets set, otherwise it’s up to the fireplace installer to make sure that it’s insulated and that you actually have an air barrier in front of the insulation. If you’re not using spray foam behind your fireplaces, and you’re just using a fiberglass batt insulation or maybe a blown-in cellulose, you still have to have, ideally, drywall on top of that insulation, and if that fireplace is already there, good luck.
Jason: Yeah, and as I’ve learned over the years, I try to let the doctors doctor, as one of my client taught me one year ago or two. I don’t like my fireplace guy to be my insulating contractor, and that’s why we got a guy like Eric to come in and say, “Hey, you need to get your insulator in here. Insulate that wall properly before that fireplace gets installed.”
Greg: If someone really likes the aesthetic of a burning flame, a real fire place, is that, in your opinion for comfort, is that best to put out on a back patio or a porch or something, and not really have inside the house envelope? Is that one work around?
Eric: Well if it’s on the back porch are you saying that it’s on the exterior wall of the house, or it’s actually-
Greg: Just sort of separate. I know a lot of people have fire pits, or chimneys, or fire places…
Eric: Yeah, that would be a lot better way to go. Keep the fire place outside the house. One word of caution, don’t ever install a ventless gas fireplace in a house, especially if it’s a really tight, well insulated house because those things, they put off carbon monoxide, they add extra moisture to the air. If it’s not venting those fumes and everything to the outside, the only place it can go is inside the house. I really hate ventless gas fireplaces.
Jason: That’s good. I guess in a perfect world we wouldn’t install a fireplace, but we’re building luxury custom homes and the great room, and dining room is always a focal point. Unfortunately for me, most of my customers like a wood burning fireplace, so we are violating Eric’s recommendations I guess.
Eric: The thing that you got to make sure that you get across to your clients, to the homeowners is that there’s going to be a trade off. If you want a really comfortable house, and you want a high-performance house that’s going to have lower utility bills, then you need to insulate it really well, and it needs to be air sealed really well, but if you also want the fireplace then there’s going to be some give to that. You’re going to have a leak in your house because of that fireplace, and oh by the way, if you have a natural wood burning fireplace inside the house, it takes the air, the oxygen from inside the house to burn that fire. Then that air goes straight out the fireplace flue.
If you have a really tight house and you let that fireplace burn for a while, it’s going to exhaust all the air, all the oxygen from inside that house at some point and if you don’t have make-up air coming in from outside directly to provide the oxygen for that fireplace, you could back draft the fireplace, you could kill everybody in the house. I hate to be dramatic like that, but that is a concern.
Jason: Right. Yeah, so explain that to the listeners. If you take all of the air out of the house … I mean is that … I guess tell us what that’s going to do. I mean are you going to dry up the house? Talk to us a little bit.
Eric: When air leaks out of a building the same volume of air that leaks out has to come in from somewhere. What I’ve seen in some situations is they will, the builder will install an intake pipe that will go from the outdoors, and whenever the fireplace is either turned on whether it’s natural gas, or if it’s a wood burning, they might have a switch on the wall, or some automatic damper that will open to provide the oxygen to come in for that fireplace to burn properly. If that doesn’t happen then basically the fireplace is going to burn the oxygen that’s in the house until there’s nothing left.
When a fireplace burns, typically about 300 cubic feet of air leaves the house per minute. Per minute. If you have a house that’s, you could do some math and say “I have a 5,000 square foot house and it’s eight foot walls or whatever, so I have 45,000 cubic feet of air in the house.” It sounds like a lot of air, but if you keep burning that fireplace all day long eventually it’s going to turn over all that air and it’s going to leave the house. When you have a really, really tight house, you have less of that oxygen for the fireplace to burn unless you provide the make-up air. Hopefully that makes sense.
Jason: Yeah. No, absolutely. That’s-
Greg: But then what happens?
Eric: What happens is it looks for air from somewhere else. Then the fire basically will back draft into the house. It won’t be able to continue that draft.
Greg: It’ll jump to where the oxygen is.
Eric: It’ll come into the house. It’ll go wherever else it can. You’ll get smoke that rolls up on the fireplace. If you’ve ever noticed in a house where it takes a minute for the fireplace to establish a draft, usually that means that either A, the house is really tight, or B, there’s a bigger leak somewhere in the house that’s drawing the air from the fireplace out.
Jason: You’re saying, just … Maybe some people … we ought to back up here. A fire needs air to draw up through the chimney.
Jason: You’re saying that if … I’ve been there before where you’re trying to light the fire and you can’t get it to draw, and all of a sudden you get smoke in the room.
Jason: You got to make sure that you got plenty of oxygen, or that fresh air into the house to get that fire to draw.
Eric: You know we were in a house recently over in southern Indiana where they had a tongue and groove wood ceiling in the living room right next to the fireplace. The tongue and groove wood ceiling didn’t have any drywall behind it, so it was basically just a big hole in the house. This guy had foamed the whole house, put in geothermal and everything, and when we did our blower door test, it was like four times leakier than it should be. We just said, “Stop right here. You’ve got to fix this problem right now, or else the fireplace is never going to work.” The tongue and groove wood ceiling had more holes in it than the fireplace did. When the fireplace starts up, it’s going to want to naturally draft out the top of the ceiling from instead of out of the fireplace. It’s a bigger hole.
Greg: All right, one more question about the fireplace. We’re going to have this … this is going to be a three hour episode. It’s really interesting…
Eric: Maybe we’ll get through top five.
Greg: We can always come back for more. The HVAC system doesn’t … You had those vents up in the walls of your house. There’s supposed to be air coming back into the room. That doesn’t count as air coming back into the-
Eric: No, because you have supply ducts that push air into the room, and you have return air ducts that pull it out of the room, so those are all inside the house. That’s-
Greg: That’s all neutral already.
Eric: That’s not pulling air from outdoors.
Jason: You’re recycling the air that’s in the house.
Greg: If the fire takes it away there’s nothing left to-
Eric: Correct. They have some things, you have some HVAC contractors will install what’s called an air cycler. That’s like a six inch or eight inch duct that runs from the outside to provide fresh air and it ties into the return side of the duct work. That’s one way that you can supplement and bring in fresh air. Another way is an ERV or an HRV, which is basically a very fancy way to bring fresh air in without bringing in all the moisture and the heat that comes with it. Fireplaces can definitely be challenging in new homes.
Jason: Thanks for joining this episode on fireplaces.
Greg: Number Two!
Jason: Yeah, let’s move on to number two here. Eric, what have you got for us?
Eric: Okay, so number two I have knee walls. A knee wall is any wall that faces an attic space. If you’re building a house and it has vaulted ceilings, typically the triangular portion around the vaulted ceiling that faces that attic, that’s going to be a knee wall. Or, if you’re building a story and a half house, and the story that is in the attic essentially, that second floor is basically surrounded by attic space.
Jason: I guess if the listeners can think of like a Cape Cod house, or maybe a finished room over a garage where you’ve got that voided space behind a wall.
Eric: Yeah, most of the time knee walls are shorter walls. That’s why they call them … They’re knee height. They’re really any wall that faces attic space. If you think about in the summer time especially, those walls are between, your attic 120 or 130 degrees, and your house you’re trying to keep around 70, 75 or something in the summer time, so you have a huge temperature difference between the inside of the house and the attic space, and those knee walls are the only thing separating those two extreme temperatures. In my opinion those walls should be insulated better than your exterior walls because, summer time again, outside it could be 95, but your attic is 130, so you have more temperature difference between the house and the attic than you do between the house and the outside.
Knee walls are a big issue that I find, and typically it has to do with the way that they’re framed. If you’re using trusses a lot of times it’s more challenging to insulate those walls properly. A lot of times they also don’t have the zip walls that you guys use, or OSB on the attic side of those walls. If the builder is using fiberglass or cellulose in those wall cavities and they don’t have a sheathing facing the attic, that hot or cold attic air will move through that insulation.
Jason: No matter what … Yeah.
Eric: It’s just going to make it darn near ineffective really.
Jason: What’s the best way for somebody to … I mean I guess each knee wall probably could be treated different depends on how it is on that particular house, but how should somebody go about making sure their knee wall space is insulated properly for ideal home comfort?
Eric: It starts with the framer, really. The framer needs to make sure that A, he’s got six sides to those wall cavities. It needs to have a left and a right, a top and a bottom plate, and there needs to be something on the attic side. Preferably, I like to see zip walls or plywood, OSB. The best product that you could use would be like a foam board, something that has insulated sheathing, so that you have actually insulation behind all those studs. Not only do you have insulation within the wall cavity, you have insulation behind all the framing to prevent that heat gain from coming through. You can do it with spray foam, you can do it with fiberglass or cellulose, but it really starts with the framing.
Jason: If you’re doing spray foam, would you spray foam the knee wall, or would you go ahead and just do the exterior wall at that point?
Eric: If you’re using spray foam and you don’t have a sheathing on the back of the knee wall facing the attic space, that’s a good opportunity to wait until the dry wall’s installed in the house and then have your spray foam guy come in after that and then foam the backside of all those knee walls. They’ll spray it right up against the dry wall and cover all the studs in one shot. That’s a good way to approach it as well.
Greg: Then I just want to touch base, what you’re talking about comfort in the house, you’re just talking about literally the user, the buyer, the owner, you want the temperature to be the same in the living room as it is in the bedroom, as it is wherever they want it. Instead of in this situation, the room above the garage being 20 degrees cooler or hotter depending on the season than the bedroom itself or something. That’s what you’re talking about right? Evening everything out and making sure-
Eric: Yeah, making sure your thermal boundary is nice and insulated.
Greg: These are all trade-offs, right? You spend more time and money setting it up properly. Ideally though, your home is more comfortable and your utility bills are less.
Eric: Yeah, and if you insulate and air seal the house correctly, then you should also need a smaller heating and cooling system.
Eric: That’s knee walls.
Jason: All right, so that wraps up that one, so I guess that takes us to number three, Eric.
Eric: Number three is related to the knee walls, vaulted ceilings or tray ceilings. Again, they’re really cool architectural features that people like to have in new homes, and they look great, but again, you just got to make sure that they’re being insulated properly. If you have a vaulted ceiling where you’ve got, maybe it’s the bonus room above the garage as an example. You’ve got the sloped part of the ceilings that are on an angle. If the framer only puts a two by six or a two by eight rafter in there for you to fill with insulation, then that’s only really enough space for a R19 or maybe an R25 insulation, which is less than what code requires. For vaulted ceilings you have to have an R30 in that vaulted ceiling.
Jason: Which is how many inches?
Eric: It’d be like 10 inches of fiberglass, or cellulose. You can get an R30 with closed cell spray foam, five inches of closed cell spray foam or less would be an R30. With those vaulted ceilings you just need to make sure that if you’re going to use fiberglass for example, you need to have a big enough cavity so that you can an R30 batt or an R38 batt in there. Or, if you’re going to use a blown-in product like cellulose or a dense-packed fiberglass, again, it still needs to have that depth. If you’re going to spray foam or something like that you don’t necessarily need as much depth, but you have to use a more expensive material. Maybe less framing, but more expensive insulation, or vice versa. Vaulted ceilings are right up against the roof deck. You got a lot of heat gain that comes through there when the sun hits it so they need to be insulated well. Bonus rooms are another example of that.
Jason: Is there, do you prefer any method over the other? Spray foam versus fiberglass versus blown-in or is…
Eric: I’m a fan of spray foam and the dense packed cellulose for vaulted ceilings. If you’re using fiberglass it just needs to be packed to the correct density. Sometimes it’s hard to get the installer to pack it to that density. With cellulose, it’s nice because once it’s packed it’s packed. It’ll settle a little bit, but you can pack cellulose a lot easier than you can fiberglass. Fiberglass, you can just keep packing and packing and packing and packing and packing. I mean you can get the density of fiberglass a lot higher than you can cellulose, but you’ll through a whole lot more material as well. There’s another trade off.
Jason: Got you. Got you.
Eric: It’s important that the insulation installer knows what he’s doing.
Jason: It sounds like it. That can be key.
Greg: Yeah, and it sounds like you need to have several people on the same page here. The builder has to put the framing in place to support the kind of insulation that you think is best. Then, do you check on the front end? Do you talk to the insulation installer? Do you come and check afterwards? How does that-
>Eric: Typically, we come in after the insulation guy is done, so we don’t usually get an opportunity before he comes and does the insulation, but for larger custom homes, we do framing inspections a lot. We’ll come in and do a walk-through as they’re maybe getting ready to do mechanicals or something like that, and say, “All right these are the areas that you need to pay attention to when you get to that stage.” We can head-off some of those problems before they get too far down the road.
The other thing I’ll say about vaulted ceilings real quick is people love to put recessed lights in those areas, and speakers, and stuff like that. If you think about … If you’re putting a recessed light into a vaulted ceiling and you’ve only got maybe 10 inches of space, or 12 inches of space there, that recessed light is going to eat up a big section of that space. Behind that light, you might only have an inch or two of insulation. I try to encourage builders if they’re going to put what looks like a recessed light into a vaulted ceiling, think about doing the new kind of flush mount LED lights that look like recessed lights, but they don’t actually take up that space. I’ve seen sweating occur, I’ve seen condensation and dripping and stuff like that from those lights just creating basically an uninsulated space, a void in the ceiling.
Jason: Is there any issue with putting the spray foam or insulation right up against the roof deck?
Eric: There’s no issue with it as long it’s installed to the proper depth. It needs to be at least five or six inches thick. It needs to be sealed where it meets the soffit at the bottom. If you’re going to do a conditioned attic, or a vaulted ceiling with spray foam, you just need to make sure that there’s no opportunity for outside air to come in and bypass that insulation. It’s one of the things that we make sure of at the pre-drywall inspection.
Jason: Yeah, that pre-drywall inspection is always an eye-opener for me. As soon as I think I’ve got it all figured out, Eric comes in and shows me that there’s a reason I pay him to come in and tell me I’m wrong.
Greg: It’s nice on the consumer side to hear this conversation because this is stuff that I would never, I’m just not in this field. I would never, ever know what to look for, what to pay attention to.
Eric: The reality is most people in the construction industry, unless you’re a builder, or unless you’re an insulation contractor, you’ve been involved with fixing these problems. Most trades are not aware of these issues either. It’s kind of like, unless it’s happened to you, you don’t know about it type thing.
Greg: Right. You just mentioned mechanicals and duct work, and things like that. I’m assuming that’s on your list as well somewhere?
Eric: Yeah. Actually duct work is the next one on the list.
Greg: Imagine that.
Jason: Come on now. That was too … Is this scripted? What’s going here? What number is that? Four? Number four.
Eric: This is number four. Duct work. I see more problems with duct work than I care to see. It’s definitely one of the top five. There’s a plague in the industry with improperly sized duct work. It kind of is an industry-wide issue where there’s not a lot of training on how to properly size duct work and lay it out. What I see a lot times is you’ll have a brand new system that’s installed. They’ll pay for the 95 or 98% efficient gas furnace, and maybe it’s a dual fuel system with a heat pump on it as well. They got this really fancy, really expensive box that creates the heat, but it’s attached to a duct system that can’t move that heat through the house efficiently.
I compare it to putting a Ferrari engine into a Ford Escort. The transmission and everything else can’t handle that engine. It’s the same way a duct system that can’t handle the air flow, or the heat that’s supposed to move through it. Duct sizing is an issue. The layout tends to be an issue, especially when they’re using floor cavities and wall cavities as return ducts, which is extremely common in the Midwest. If they’re not fully ducting the system, if they’re using building cavities, then they’re typically not going to get the air flow through it that they need to.
Jason: Do you recommend on returns that that whole cavity is panned out? What’s the best way in your opinion to get that return done properly?
Eric: The best way is to actually use duct work for the returns if you can. A lot of times it comes down to the architect and what’s he’s allowed for spacing in the house. If the architect hasn’t provided enough space for the HVAC guy to put in the duct work that he needs, then he’s going to be handicapped before it ever starts. This is as much a design and a framing issue as it is an HVAC issue. You’ve got to have everybody on the same page from the beginning.
There’s nothing necessarily wrong with panned-in floor cavities and wall cavities as long as they are the proper size and as long as they’re sealed properly, which is my next point. Sealing duct work is extremely important to providing the air flow to the bedrooms that you want.
Jason: Is that necessary in new construction houses, if it’s inside the building envelope to seal the duct work?
Eric: Kentucky has this silly code that says that you have to seal duct work, but only if it’s outside the conditioned space. There’s some logic to that where you want to make sure that the duct work is tight if it’s in your attic. You also want to make sure it’s tight if it’s inside the house. If you’re not sealing the duct work, and it’s inside the house, and say you’ve got a bigger house, and maybe it’s 100 feet long. You put the furnace on one side of the basement, and so air has to move all the way to the other side of the house. If that duct work is not sealed, it’s going to leak most of that air closest to the furnace. That side of the house is going to get more air than the opposite side of the house. It’s like with plumbing, you wouldn’t install plumbing in the house that leaks. You don’t want water spilling all over the basement, and everything else.
Jason: Right. Right.
Eric: Same concept. Sealing duct work inside the house causes comfort problems … Or, not sealing it causes comfort problems. It could also, if you have natural gas appliances, like the old school gas water heaters, or the older gas furnaces and you’ve got return side leaks that are right next to that furnace or water heater, it can actually back draft those appliances because it’s sucking the air from the room that it’s in, and it’s pulling air back down the flues. Yes, it’s important.
Jason: How would somebody go about … We hear that you can … The same goes for geothermal systems, any type of furnace systems. You can have the best, most expensive system out there, but if your duct work is not right, you’re going to have issues. On a new construction home, or even a retro fit, how do you go about making sure you’ve got the proper duct work in place?
Eric: It comes down to the duct sizing. If an HVAC contractor knows what he’s doing, he should be doing what’s called a Manual D. It’s a duct sizing calculation. The duct size depends the air flow required to move through it. The air flow required to move through it depends on how big the air conditioner, or the furnace is. You basically need, the rule of thumb is about 400 cubic feet of air per ton of air conditioning. If you have a four ton air conditioner in your house, it needs 1,600 CFM, cubic feet of air to move through that system.
What we can do is, there’s duct sizing charts. What I’ll do is, if I go through a house and it’s got some comfort issues, or we’re going through a planning stage, I’ll say, “All right. Here’s the size of the system that you need given how you’re going to insulate the house. You’re going to put a four ton system in the house. It needs 1,600 CFM of air. This is the size duct work that you need to move 1,600 CFM of air. We need to make sure that not only is it going to move it right next to the furnace, but it’s also going to move it down the trunk line and throughout the entire system. You kind of work it backwards. There’s a chart that we work off of.
Jason: Got you. It does … You need to know what type of insulation. That’s interesting you say that. Why is that important to what you’re doing?
Eric: Insulation … When you do a heating and cooling load calculation on a building that is when you take into account how tight the house is going to be, what type of insulation you’re using, the type of windows and doors that you’re putting into the house, as well as the orientation to the sun. All those things affect the size of the heating and cooling system that’s needed. Once we have that down, and we know what size is needed, then we say all right, here’s how big the duct work needs to be to move this amount of air through the system to work efficiently.
Greg: Is that something you can measure? Using your example of trying to move the air 100 feet from one side of the house to another, or further if you’re going upstairs I guess, can you measure that coming out of the-
Eric: Absolutely. Yeah.
Greg: Is that part of what you do?
Eric: Yeah. We can do, we have what’s called flow hoods, and we basically put those flow hoods over top of the supply registers, or the return ducts, and when the system’s running we can tell how much air is actually coming into the room. It’s one thing that we would do as part of a pressure balance, or making sure the duct system is balanced.
Jason: There’s a lot in the duct work. My goodness.
Greg: Yeah, absolutely.
Eric: There’s a lot in duct work.
Jason: Again, that probably could be a whole separate issue. Maybe we’ll move on to our number five to close out this episode.
Eric: Okay, so number five on my list here is basements. Everybody’s been in a house where the basement is cold year round, and it seems like there’s nothing that you can do to change that fact. It’s in the ground, the ground is always cold so you just take it for granted that the basement is always going to be cold. Again, it goes back to the code. Kentucky adopted an energy code, back in 2012-
Greg: I thought that’s why people built basements, right? To have a-
Eric: Have a cold basement.
Greg: Cold place all the time. That’s right.
Eric: Put your wine and stuff down there. Yeah. You know the Kentucky’s building code, and Indiana, most of them in the United States require that you insulate foundation walls now to at least two feet below grade. Once you get below two foot under the ground, it’s about 55 to 57 degrees year round. Concrete foundation walls have about the same resistance to heat transfer as a single pane glass window. Most people, it blows their mind thinking about that.
Jason: What R factor is that?
Eric: An R1, so about eight to 10 inches of concrete has an R1 insulation value.
Jason: So virtually no insulation.
Eric: Virtually none. Concrete is really good at absorbing heat and releasing heat slowly. It’s also good at absorbing moisture, water vapor and releasing it slowly. With basements nowadays, you need to make sure you that you insulate at least the top four feet, if not the entire foundation wall. The best way to do it is really using either a foam board product, or a spray foam that’s directly applied to the concrete. If you’re doing a foundation, or a finished basement and they’re framing up the walls, and all they’re doing is putting fiberglass in those wall cavities, typically that insulation is still going to be an inch or two off of the concrete, so you have a space behind the insulation where air can circulate. That kind of application is not as effective as when the insulation is directly up against the foundation, against the concrete.
The other thing that tends to make basements cold is, it goes back to the duct work. Again, you’ve either got not enough air going into the basement, or not enough air going back to the furnace from the basement. If you’ve got a five or 10 degree temperature difference between the basement and the first floor, it’s either A, it’s either going to be an insulation issue, or B, it’s going to be duct work issue. Basements are common areas where we have home comfort complaints.
Jason: Yeah. I think people just don’t realize the foundation is just not providing insulation, so it’s almost like having an open window down there with an un-insulated wall, or really an improperly insulated wall down there.
Eric: Yeah. There’s several ways that you can insulate them, but like I said, foam board or spray foam is going to be the best way to do it. You can insulate on the exterior of the foundation walls, which I know some builders do. They’ll put one or two inches of foam board from the footer all the way up to grade. That’s a great way to do it, but you still will typically have a foot or two where the concrete sticks out of the ground that still has to be accounted for and insulated.
Jason: If you had your choice of product, price not an issue, how would you prefer to insulate your basement wall if you’re building a new house Eric?
Eric: I think if price wasn’t an issue I would use insulated concrete forms, ICF’s, and basically what that is, is it’s kind of like a Lego that has two inches of foam on the outside, and two inches of foam on the inside, and then you pour concrete in the middle.
Jason: All right, I retract my statement. You already have a foundation in the ground, that’s eight inches-
Eric: You said price wasn’t an object.
Jason: Nine inches of concrete. How would you insulate that space?
Eric: Have we back filled the grading on the outside?
Jason: We have not back filled yet.
Eric: We have the opportunity … I would insulate the exterior foundation wall, probably with two inches of foam from the footer up to grade, and then on the inside I would spray foam it from the rim joists down onto the concrete, and it come down at least two feet if not four, and overlap the outside insulation with the inside.
Jason: Okay. Good stuff there.
Greg: Then do you not have to worry about, I don’t even know how you would do it, under the basement floor, or is there enough air to serve as a buffer? Is it just so impractical that it’s not even worth it?
Eric: You’re already typically seven to nine feet below grade. The basement floor is not really cost-effective to insulate that in our climate zone. If you go north, you go into Canada, then sure, but around here, I don’t really recommend it. It’s … You can always do it.
Jason: I guess the only exception would be if it’s a walk-out possibly, right?
Eric: If it’s a walk-out. If it is a walk-out then that slab would have to be insulated per code, so the part of the slab that actually faces the outside, the daylight portion, you got to insulate the exterior portion of that slab for sure. One other way that you can make basements more comfortable, and I love this approach is doing a radiant heated floor. You got a hot water system that basically circulates hot water through the floor. It’s all underneath, and you will never have a cold basement ever with that application.
Jason: Man, fascinating stuff. I’m ready to start designing my next house. Eric, I think we’re going to call it a day with Top Five of the Top 10, and hopefully you can can hang around, or come back next week and we can hit maybe five more home comfort areas that we should look at when building a new custom home.
Eric: Sounds great.
Thank you for joining us on this episode of the Louisville Custom Home Builder podcast. If you’re looking to build a home, and would like to reach out to Jason with any questions about the process, or maybe just your individual needs and desires, please visit the website at artisansignaturehomes.com. We appreciate your time with us today, and look forward to bringing you another episode next week.