Heating Systems
A variety of technologies are available for heating your house. In addition to heat pumps, which are discussed separately, many homes use the following approaches:
Furnaces and Boilers 
By far the most common way to heat a home.
Wood and Pellet-Fuel Heating
Provides a way to heat your home using biomass or waste sources.
Electric Resistance Heating
Among the most expensive ways to heat a home.
Active Solar Heating
Uses the sun to heat either air or liquid and can serve as a supplemental heat source.
Radiant Heating
Can draw on a number of energy sources, including electricity, boilers, solar energy, and wood and pellet-fuel heating.
Small Space Heaters
Less efficient than central heating systems, but can save energy when used appropriately.
While forced-air heating systems rely on the same type of ducts used by heat pumps and air conditioners, water and steam heat systems use radiators that only deliver heat. To learn about maintenance and retrofit options for these systems, see: