A conventional furnace is overkill in a small, well-insulated house. Here are some better options.
Most U.S. homes are heated with either a boiler (which distributes heat by circulating hot water through tubing) or a furnace (which distributes heat by circulating hot air through ducts). Since new homes often include central air-conditioning, which requires ducts, furnaces have become far more common than boilers.
[To read more of Martin Holladay’s article from the February/March 2011 issue of Fine Hombuilding, click the link below.]