Got questions about luxury custom home building in Louisville, KY? There is no better source for answers than Jason Black, the president and owner of Artisan Signature Homes, Norton Common’s best known and most accomplished custom and luxury home builder. Today he’s on the Custom Home Builder Podcast, along with Eric George from Building Performance, to talk about how to make a new home more comfortable and efficient.
“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,” says Jason Black. “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 verify that the homes we build are up to the highest standards.”
Here are five of the top comfort issues found in new homes:
Fireplaces – Eric George recommends installing a natural gas insert or an electric fireplace that gives you the cozy look, without the drafts of a traditional wood-burning hearth. Jason Black explains that you can have a super-efficient, all-foam house, but if you’re attaching an 8-18” flue, there are many holes in the insulation, going right through the building envelope. “It takes a lot of air with it,” adds George. Another point to consider is that the fireplace must be in the original architect plan; otherwise, it’s a challenge to insulate around it. “I don’t like my fireplace guy to be my insulation contractor,” Black says. A wood-burning fireplace out on the back patio would be a better bet for people who like that aesthetic. George warns against installing vent-less gas fireplaces in a well-insulated home, as it puts off carbon monoxide and added moisture to the air.
“Unfortunately for me, most of my customers like a wood burning fireplace, so we are violating Eric’s recommendations,” Black says. He explains to his luxury custom home building clients that there is a trade-off. The house can’t be built as tight as possible – air-sealed and insulated really well for high performance and low utility bills… AND have a wood-burning fireplace. When you put in a fireplace like that, there needs to be plenty of fresh air coming into the home (usually down through the chimney or sometimes through an air cycler or ERV); otherwise, the fire will burn up all the available oxygen in the house and potentially back-draft into the home.
Knee Walls – A knee wall is a short wall, usually under three feet high, which supports the rafters and faces the attic space. In the summer, these walls are between the 120-130 degree attic and the 70-75 degree home. “Those knee walls are the only thing separating those two extreme temperatures,” explains George, so these walls need to be insulated even better than the exterior walls to maintain a comfortable temperature inside.
“Knee walls are a big issue that I find,” says George. “Typically, it has to do with the way that they’re framed.” It’s more challenging to insulate trusses, for example. If the builder uses fiberglass or cellulose insulation and fails to include zip wall or OSB sheathing facing the attic, then the hot or cold air will still pass through the insulation, no matter what.
To properly insulate a knee wall, the framer needs to make sure that he has six sides to the wall cavities, with left, right, top, bottom and attic side plates. George likes to see zip walls, Oriented Strand Board, or plywood. The best product possible is a foam board with insulated sheathing. You can do it will spray foam, you can do it with fiberglass or cellulose, but it really starts with the framing.
It may cost more money to set up the structure properly, but you are more comfortable with lower utility bills in the end. “If you insulate and seal the house correctly, then you should also need a smaller heating and cooling system,” George adds.
Vaulted or Tray Ceilings – Vaulted ceilings or tray ceilings are a cool architectural feature that people really like for their new homes. Again, there are insulating considerations in the building phase. Where the building code may only require R19 or R25 insulation in the 2×8 rafter in the bonus room over a garage, a vaulted ceiling would require R30. “Vaulted ceilings are right up against the roof deck,” George explains, “so you’ve got a lot of heat gain that comes through when the sun hits. They need to be insulated well.”
You can get an R30 with five inches of closed cell spray foam or 10 inches of fiberglass. With spray foam, you don’t necessarily need as much depth or as much framing, but you’re looking at a more expensive material. Personally, George is a fan of the spray foam and the dense-packed cellulose for vaulted ceilings. “Once it’s packed, it’s packed,” he says. “With fiberglass, you can just keep packing and packing and packing. You can technically get the density higher, but you’ll go through a whole lot more material.”
Recessed lights or speakers are often installed in vaulted ceilings, which eats up some of the space for insulation. “I try to encourage builders to use the new kind of flush-mount LED lights that look like recessed lights, but they don’t actually take up that space,” George says. Builders need to be careful to make sure the lighting isn’t sweating or causing condensation drips that create a void of uninsulated space in the ceiling.
For Black, these issues are all hammered out during the pre-drywall inspection. “That pre-drywall inspection is always an eye-opener for me,” Black chuckles. “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!”
Duct Work – Improperly sized duct work is one of the biggest problems in the industry, says George. There is not nearly enough training in this department. “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,” George says, “BUT it’s attached to a duct system that can’t move that heat through the house efficiently.” It’s like putting a Ferrari engine into a Ford Escort, he says, where the transmission and everything else can’t handle the engine.
The layout is another issue, especially when floor cavities and wall cavities are used as return ducts, which is extremely common in the Midwest. “If they’re using building cavities and not fully ducting the system, then they’re not going to get the air flow through it that they need,” George says.
The best method is to use duct work for the returns. This trickles all the way down to the architect, who must allow enough space for the proper HVAC. “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,” George clarifies. Sealing the duct work is important in providing air flow to the bedrooms. When duct work is not sealed well enough, there will be a furnace on one side of the basement that moves air all the way to the other side of the house, but leaks most of the air out closest to the furnace. By comparison, “You wouldn’t install plumbing in the house that leaks,” says George.
The best HVAC contractors use a duct sizing calculation known as Manual D. The rule of thumb is that you need about 400 cubic feet of air per ton of air conditioning, so if you have a 4 ton air conditioner in the house, it needs 1,600 CFM of air to move through that system. There are duct sizing charts that professionals use to work through comfort issues related to duct efficiency.
There are many factors that go into the calculation of the heating and cooling load of a house – how tight the house is, the type of insulation used, the type of windows and doors, even the orientation of the sun. The pros can put flow hoods overtop the supply registers or return ducts to see how much air is coming into the room, which will reveal whether the duct pressure is balanced or not.
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,” says George. Ideally, a home will not have more than a 5-10 degree temperature difference between the first floor and the basement. If that is not the case, it’s either a duct work issue, where not enough air is getting down into the basement – or, most commonly, an insulation issue.
The ground is naturally cold. Many people liked having a cold basement for food and wine storage. In Kentucky, foundation walls go two feet under the ground, where it’s about 55 to 57 degrees year-round. Concrete has about the same resistance to heat transfer as a single pane glass window – about an R1 insulation value. “It blows most people’s mind thinking about that,” according to George. “Concrete is really good at absorbing heat and releasing heat slowly. It’s also good at absorbing moisture, water vapor and releasing it slowly.”
Commonly, he sees builders putting fiberglass insulation in the wall cavities, just an inch or two off the concrete, so there is space behind the insulation where air is circulating. Even though the Kentucky building code only requires the top two feet of the foundation insulated, George recommends that the top four be done, if not the entire foundation wall – using a foam board product or spray foam directly applied to the concrete. If price were no issue, George would use Insulated Concrete Forms – which are basically like Legos with two inches of foam on the outside and two inches of foam on the inside and concrete poured in the middle.
George explains: “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.”
One way to make basements more comfortable is to do a radiant heated floor, which includes a hot water system beneath the home that keeps the entire room warmed up.