Selecting the fuel and heating system best suited for your needs depends on the following factors:
- The cost and availability of the fuel or energy source
- The type of appliance used to convert that fuel to heat and how the heat is distributed in your house
- The cost to purchase, install, and maintain the heating appliance
- The heating appliance's and heat delivery system's efficiency
- The environmental impacts associated with the heating fuel.
One somewhat simple way to evaluate heating options is to compare the cost of the fuel. To do that, you have to know the energy content of the fuel and the efficiency by which it is converted to useful heat.
Fuels are measured in physical units, such as gallons of oil or propane, cubic feet of natural gas, or kilowatt hours of electricity (kWh). They are also measured by heat content. In the United States, the most commonly used value for expressing the energy value or heat content of a fuel is the British thermal unit (Btu). One Btu is the amount of energy needed to raise the temperature of one pound of water 1°F, when water is at about 39°F. One "therm" is 100,000 Btu.
The chart below provides a list of typical heating fuels and the Btu content in the units that they are typically sold in the United States.
|Fuel Type||No. of Btu/Unit|
|Fuel Oil (No. 2)||140,000/gallon|
|Natural Gas||1,025,000/thousand cubic feet|
|Wood (air dried)*||20,000,000/cord or 8,000/pound|
|Pellets (for pellet stoves; premium)||16,500,000/ton|
The efficiency of the heating appliance is an important factor when determining the cost of a given amount of heat. In general, the efficiency is determined by measuring how well an appliance turns fuel into useful heat. (The condition of the heat distribution or delivery system also affects the overall system efficiency.) Many types of space heating appliances must meet minimum standards for efficiency developed by the U.S. Department of Energy. This next chart provides average efficiencies for common heating appliances.
Environmental and Efficiency Considerations
In addition to cost, you might consider the environmental impact of your heating fuel. You probably generate more greenhouse gases by heating and cooling your home than by any other activity, including driving.
Burning natural gas, oil, propane, wood, or pellets in your home with a high-efficiency furnace or boiler can be a very efficient way to deliver heat to your home. Of all these choices, natural gas burns cleanest.In the NW, due to hydro power, using a heat pump is one of the most cost effective and clean ways to heat your home.
Of course, the cleanest fuel for heating your home is solar energy, which produces no pollution at all. In most homes, solar energy will merely supplement the main heating and cooling source, although many are building homes that aim to consume net zero energy over the course of a year.
Choosing a Heating and Cooling System
When choosing a heating and cooling system, there is no one answer; it's largely a personal choice. For existing systems, your choices are pretty much set by the limitations of replacing the system with something significantly different. But for a new home, if your building contractor doesn't impose limitations, the choices are wide open.
Choosing between systems depends in part on your fuel options, but also on your preferences. Here are some questions you might consider:
- Do you want a central air conditioning system? If so, are any heat pump options—particularly geothermal heat pumps—practical for your home?
- If you don't want central air conditioning, could a baseboard hot water system or a radiant heating system meet your needs?
- If you need to cool your home but don't want a central air conditioning system, could a room air conditioner, or a ductless mini-split system meet your needs?