Good: Three of our bedrooms were extremely hot and we thought it was because of our attic insulation. High Performance Homes did an energy audit and found that it wasn't our attic insulation that was the problem, it was the amount of air that was leaking out of our house at the attic. We had them replace fix the air leaks and replace a few of our rotting windows and now it's like we are living in a new house. It is so much more comfortable and our gas bills are way down. I really recommend them.. Bad: We hadn't found them sooner. Improvements: None.