Consider Spray Foam When Adding/Replacing Attic Insulation

Generally when you think about an attic, you imagine it as either really hot or really cold. In the summertime, attics can reach temperatures of 150-160 degrees. In the winter they can get well below freezing.

The idea is that you should vent your attic with outside air and only insulate the area between your attic floor and the ceiling from the level below. Basically treat the attic as if it were outside. To do that, the soffits around your house are vented allowing air to come in through the soffits and go out through vents placed in your roof. The problem though is that in the summer, roof shingles get extremely hot, and a lot of that heat is transferred into the attic.

Meanwhile, if you're lucky enough to have your HVAC unit in the attic, the unit is working is less than optimal conditions. In the winter, it is sending hot air in the ducts through a freezing cold attic and the exact opposite is happening in the summer. But now there is a solution:

Instead of insulating the attic floor, why not insulate the attic ceiling (the underside of the roof). Don't ventilate the attic. Use closed cell insulation to prevent moisture and don't insulate the attic floor at all. Basically you treat the attic as part of your conditioned space.



I'd love to be able to tell you how much you'll save with this setup and how quickly you'll see a payback, but honestly I don't know. I haven't done it or been able to do a cost comparison. But the idea makes sense and sounds way more logical than letting your HVAC equipment push cold air through barely insulated ducts in a 150 degree attic all summer long.

I do know that at one point there were some concerns about moisture build-up and about the shingles getting too hot since they could not vent downward. However, it seems that these problems can be avoided with the right precautions.

Again, check prices and do the analysis before deciding, but definitely consider this as an option when looking into insulation in the attic.