I'm considering get air sealing done in my house, along with a new heating and cooling system. If I attain a 25% saving in heating energy, I qualify for all kinds of great incentives. The heating system I'm looking at gets me 15% of the way there (from 80% to 95% AFUE). The other 10% comes from insualting and air sealing. The contractor that I am negotiating with will subcontract the air sealing out. My question, what is the basis to know when the air sealing is acceptable? I have a fire place (with wood buring insert) so the house can't be too tight and from a health point of view I need a certain amount of fresh air. Is the criteria to meet the infiltration rates used in the "Manual J" load calculation (that the contractor has to do as part of the application process for this special incentive from the state)? Also, at what point would it be considered acceptable to have the contractor submit the "manual J" to me for review? I have a HVAC background (I'm a mechanical engineer) as my senior design project in college was HVAC and I worked for a HVAC contractor for a short time). I don't want to scare the contractor away, but want to ensure that the system is technically sound and I'm getting a good value.