1300 sq foot house. We got 3-4 quotes in November. All of them were pretty pricey. Cheapest was 4k, but they ranged from 4-6k. We went with one that cost us 5.2, but it met the efficiency standards for some of the rebates. Worth it IMO since we plan on being here for a while and I knew the price of gas was likely to go up this season (which it has).