The pull chain switch in my whole house attic fan broke and I ended up replacing it on a fairly hot day. While working on it I could not believe the heat coming down through the ceiling grate for the fan. 

I got online to look for an economical and easy solution.

What’s a whole house attic fan?

In case you’re not familiar, this fan is mounted on the ceiling joists in the attic after a hole has been cut out of the ceiling drywall. An aluminum grate is then installed on the ceiling side. The grate has louvers that open and close. The force of the fan blows them open and then they fall closed once the fan is turned off.

I absolutely love having a whole house attic fan and would recommend them to anyone whose house layout allows for one. I’m in a three story house and the fan is in the ceiling of the 3rd floor stairwell. I open the windows on all three floors and turn the fan on in the evening to pull the cool air in and blow the warm air up into the attic. It’s incredibly effective at cooling the house down in the spring and fall.

The down side of a whole house attic fan

That said, I never use it during the summer since it stays so hot in the Dallas area over night. I had no idea how much heat was coming down from the attic during the hot months of the year. What a waste of energy. I was sure cold came down through it in the winter as well.

As soon as I realized how much heat was coming in, and since it was summer and I did not want to go up into the attic to do it, I started looking for a friendly solution. Most sites suggested constructing some kind of insulated box to fit over the fan which would require trips into the attic to put it on and take it off. Forget it. I use the fan often during spring and fall and I would not go into the attic to place and remove a cover.

Then I found Go Green Energy Consulting DIY idea #8:

We highly recommend that homeowners with whole house fans  cover the grate with a detachable insulated cover when not in use. Lots of heat is able to radiate down from the attic through what is essentially an open hole in the ceiling. Most home improvement stores sell pre-made kits to help you do this yourself, or this is an easy project for a professional.

Finding the materials

I checked the big box home improvement stores and while they sold the foil covered bubble insulation, it was either in small widths that would have to be pieced or huge rolls that would leave me with a bunch of leftover material. It was the same with most retail places on the internet — either too narrow or too much.

I checked the web and found Innovative Insulation Inc. in Arlington, TX. I talked to them and asked if they would allow me to purchase just one yard of the insulation that was 48″ wide. I was shocked when they asked for my address and said they’d ship me a piece for free. They sent it FedEx and it arrived the next day. They obviously can’t afford to do this for everyone, but they are one place that will ship small quantities. You will note that my insulation is foil on both sides instead of white on one. I asked for white on one side, but when they shipped the wrong one for free I wasn’t about to complain and just used what they sent.

Next I went on a search for Velcro and found a 15′ roll of Velcro with adhesive. My concern was that the first time I tried to remove the cover the Velcro would stay together and it would pull off the grate or off the insulation and be worthless. Or it would not detach, but then not be strong enough to hold the insulation in place. My concerns were unfounded. The cover has been yanked off and put up multiple times and the Velcro is rock solid.

Left over material

I have an attic hatch instead of stair (another thing that requires a ladder on the third floor) and I had enough of the insulation left over to cover the hatch door in the ceiling. I had to piece it a little bit, but I stapled it on the attic side of the hatch cover to block heat and cold from there as well.

Results

I’ve gotten up and checked a few times on really hot days and there is little or no heat coming through the insulated cover.

My only issue with the cover is as a short person this is going to require a ladder each and every time I put it up or remove it and I’m not thrilled about having to keep a ladder upstairs. I tried reaching from a chair and I can just barely get hold of an edge so maybe I can take it down that way, but maneuvering the pull on/off chain under the cover while I put it up will always require a ladder. After I put it up there were a couple cool fronts during which I could open the windows so the cover had to come down. Then it would heat up again and I’d need to put if back up.

Despite the inconvenience I still feel the ease of making and using this cover is a great way to insulate from heat and cooling loss when you have a whole house attic fan.

The bubble insulation is such a cool product I did research on other things it could be used for.