Heating a house....

I recently added a 1200 sq ft addition over my garage and had a company come in and spray foam insulate it. I have a natural gas fired boiler with in floor radiant heat. I went from 2300 to 3500 sq ft and spray foamed all of the open walls. My heating bill has been within $5 of the previous year since the addition. While the spray foam wasn't cheap, not having to upgrade my boiler saved about half of the cost of the insulation.

Jason