Problems With Ducts in The Attic

Larry Janesky, founder of Dr. Energy Saver, was recently in Florida helping a homeowner solve a problem many other homeowners in the southeast have and don't even know about: ducts in the attic. While these ducts are sometimes used for heating during the winter, most of the year they are used for cooling in the warmer areas of the country. They distribute cool air throughout the house.

Sealing Ducts In The Attic

The sun beats down mercilessly almost all year and heats up the roofs to 150, 160 degrees or more, and that heat radiates down into the attic where all the ducts are located and then radiates down through the ceiling and makes our homes more uncomfortable, and we have to run our cooling more and more. One of the big issues to keep homes energy-efficient and comfortable is ducts.

Duct tape won't seal completely

. Someone has put some duct mastic here and duct mastic on top of this duct board on the trunk line and some duct tape, but the duct tape, again, that doesn't work. Now, sheet metal ducts have all kinds of joints in them and they leak terribly. Duct board is insulated. It's open face fiberglass on the inside and just this foil face on the outside, and it's soft. If this happens to be right next to where people are coming up in the attic and storing things.

Sealed and Efficient Ducts

Larry opted for using spray foam to insulate and air seal the ducts, and the connections between ducts and drywall ceiling. While newer homes, built with energy efficiency in mind, will have ducts running through conditioned areas to prevent heat gain and loss, older homes can be made energy efficient with proper duct air sealing and insulation.

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While homeowners here in the Southeast do use gas furnaces or heat pumps to heat their homes in the winter, most of the year, overwhelmingly, their cooling, the big issue is the sun. The sun beats down mercilessly almost all year and heats up the roofs to 150, 160 degrees or more, and that heat radiates down into the attic where all the ducts are located and then radiates down through the ceiling and makes our homes more uncomfortable, and we have to run our cooling more and more. One of the big issues to keep homes energy-efficient and comfortable is ducts.

This happens to be a Florida attic, and these ducts are trying to distribute the air that we cool from the air conditioning system to the rooms in the house. And inside this duct maybe would be 55 or 57-degree air, and we're running that air through a very hot attic. This attic, it happens to be February 1st today and it's morning time so it's not hot yet, but it will be soon enough even today. But in the summertime, blistering 140-degree attics we could have. And 130, 140-degree air in the attic, 58-degree air in the duct, I mean we have an 80-degree temperature difference between the air inside this duct and the air right here with just a little bit of insulation in between. So what that means is we are cooling the air, we are paying to cool it at the air conditioning system, and we're distributing it through the ducts which are located in the hot attic and we're heating the air again on its way to the rooms. It makes absolutely no sense.

And here we have a supply box that is uninsulated. You can see there is duct tape on this connection, and duct tape is good for a lot of things but not ducts, and it just gets brittle. It leaks here. All this sheet metal connections, the connection between the duct box and the drywall, the leaks there. Someone has put some duct mastic here and duct mastic on top of this duct board on the trunk line and some duct tape, but the duct tape, again, that doesn't work. Now, sheet metal ducts have all kinds of joints in them and they leak terribly. Duct board is insulated. It's open face fiberglass on the inside and just this foil face on the outside, and it's soft. If this happens to be right next to where people are coming up in the attic and storing things. And look at this duct. It's damaged and it's partially crushed. And a lot of times, we see duct board connections disconnected and they are actually air conditioning the attic just blowing all their electricity. And you're losing air from where it's supposed to be going.

But another thing about duct board is that this foil face is the air boundary of the duct. And when we get little pin holes, I can see all kinds of little pin holes from over the years, people crawling in the attic and storing stuff and they poke little holes. You can see a little hole here. And when we turn the air handler on, when the air conditioning is on, you can put your hand here and feel like an air hockey table all the cold air coming out of this duct, and we are actually air conditioning the attic and it makes absolutely no sense. So sealing the ducts, sealing all the connections to the drywall ceiling and from duct to duct and so forth, and adding insulation because the little bit of insulation here is just not enough. We need to add insulation to ducts in these very hot attics to prevent heat gain in the summertime and heat loss in the wintertime. Make big improvements because this is a terrible, terrible problem. Ducts in attics? Bad problem. And another method is to spray foam the duct to air seal and insulate them together or additional duct insulation could be added. Ducts in attics are one of the things that are going to need attention in your home for your home to be as energy-efficient as it could be. Homes of the future won't have ducts in hostile spaces like this.

Ducts will be located in conditioned spaces where there is no temperature difference between the outside of the duct and inside of the duct or much, much less and solve this problem. If you are looking to make your home more comfortable, reduce the cost of homeownership by lowering your electric and fuel bills. If you would like to improve indoor air quality at your home, call Dr. Energy Saver. We can help you.