The Best Heating Systems for Efficiency

Oil

• Oil furnaces operate with an efficiency that averages about 80 percent. New, high-efficiency furnaces may reach 89 percent. Oil is costly to extract and deliver and the supply is limited. Its cost is expected to rise substantially. In system efficiency, cost of operation and overall cost, oil ranks at the bottom as an energy source for heating.

Natural Gas

• A typical gas-fired central heating system averages 85 percent efficiency. New, high-efficiency gas furnaces can reach 97 percent efficiency while room heaters without vents can get 99 percent efficiency. Natural gas is less expensive to extract than oil and the cost of operation is not expected to rise as fast as oil. In areas of the United States where temperatures frequently drop below freezing, natural gas is among the best choices for heating system efficiency and the top choice when taking into consideration the expected operating costs.

Electrical Resistance

• Electrical resistance heating is always close to 100 percent efficient because the electrical energy is all converted to heat. For central heating systems, the efficiency goes down to about 97 percent because some energy is used by the blower. In "Energy Savers" referenced below, the U.S. Department of Energy writes that the environmental cost of electricity should be considered because most of the electricity is generated in fossil fuel power plants operating at less than 50 percent efficiency. While highly efficient in a narrow sense, electric heating is not the best choice for many U.S. residents because of high and rising electricity rates.

Heat Pumps

• Heat pumps don't generate heat but rather pump heat from one location to another. When the temperature difference between the two locations is low, a small amount of power can pump a lot of heat. Heat pumps operating in mild climates can therefore reach efficiencies of 10 or 1,000 percent, meaning that they are using perhaps 1 kilowatt to pump 10 kilowatts of heat into the home. When outdoor temperatures dip below freezing, the standard heat pump's efficiency drops drastically since it has to work harder to pump heat into the house. For colder climates, geothermal heat pumps are needed. These heat pumps are still very efficient and operate at about 300 percent.

  For milder climates, a standard heat pump is the most efficient system, even though it operates on electricity. For colder climates, geothermal heat pumps are the most efficient on a narrow basis but their high cost of installation make them less attractive than the other options such as natural gas.