Portable Heaters

• Portable heaters are small and light enough to be moved by no more than two people. Indoor space heaters are small, plug-in devices that are designed to heat individual rooms by recirculating the air in an enclosed space. Larger combustion heaters can make an outdoor patio more comfortable on a cool day. Outdoor combustion heaters burn kerosene or other liquid fuels. If you plan to use an outdoor heater, read the instructions carefully and never use it indoors.
  
  

Wood Stoves and Fireplaces

• Wood stoves and fireplaces create heat by burning fossil or biofuels. Wood is the most common of these fuels, but some stoves and fireplaces can also burn coal. Some modern fireplaces rely on natural gas fuel. Wood stoves and fireplaces require a lot of maintenance. Users must remove the ashes from fireplaces and clear the chimneys of deposits regularly.
  
  

Furnaces

• Furnaces heat the air at a central location and then send the air through the ductwork and heating vents to the rest of the building. According to the U.S. Department of Energy, furnaces that run on electric power have a greater annual fuel utilization efficiency (AFUE) than furnaces that run on natural gas, which means the heat is less likely to escape from your house before it heats the rooms. However, electric furnaces are more expensive to run than natural gas furnaces.
  
  

Boilers

• Boilers are a lot like furnaces except they heat rooms with hot water instead of hot air. The hot water flows from the central boiler to the pipes all around the house . The water pipes emit heat that eventually warms the entire building. You can control the heat in individual rooms if you heat them with a boiler. Boilers are durable, but you must occasionally inspect the pressure tank and test the relief valve to make sure that everything is running smoothly.
  
  

Geothermal Heating

• Geothermal heaters provide heat by pumping ambient underground air temperatures into a building. The air temperature below Earth's surface stays about the same regardless of how hot or cold it is above ground. As a result, geothermal heating requires no biofuel combustion. Like boilers, geothermal pumps force liquid underground and back into the pipes that run throughout the building. These pipes ultimately heat the surrounding air. Geothermal heating can dramatically cut heating costs, but the initial installation can be quite expensive.