First-time home buyer here. My exterior walls are not insulated. I had a home energy audit done to take advantage of rebates and tax credits. The auditor measured my walls and subtracted the area of windows and doors because those areas won't be insulated.

I got a quote from a reputable contractor and their estimate of insulation needed was significantly higher. I went back and forth trying to figure out why the discrepancy exists because I can only get rebates and tax credits for the amount of insulation needed based on the certified home energy auditor.

Come to find out, the contractor didn't subtract the area of the windows and said they also take into account waste and "over filling" the walls. This doesn't sound right to me. I could understand if they measured the walls, subtracted uninsulated areas, and they have a set line item listed as like a fixed amount of "10% accounting for waste" or something like that. How am I just supposed to accept that I'm supposed to pay for 200 sqft of insulation for windows and doors that will not be insulated and that part is waste and they "overfill" the walls?