According to U.S. Energy Information Agency, over 10% of the homes in the Northeast are primarily heated with electricity. Interestingly, some are the most cost effective (geothermal heat pumps) and some are the least cost effective (resistant heat). Cost effectiveness has to do with how much heat you get and the cost of a kWh. Here in the Capital Region, the cost of electricity (cost after you have paid your monthly connect charge) is typically $0.13 to $0.16 per kWh (avg. ~ $0.145/kWh); just a little more than the national average. On the other hand, a Therm of natural gas costs between $0.95 and $1.50 per Therm (avg. ~ $1.22/Therm), again a little over the national average.
To put this in perspective, the most important fact about electric heating is that a kWh of electricity contains 3412 BTUs and a Therm of natural gas contains 100,000 BTUs. So, while electricity is often “100% efficient” and natural gas heating (vented space heater or furnace with distribution system) is around 75% efficient, a million BTUs of electric heat will cost about $42.50 and the same amount of heat from natural gas will cost about $16.27.
To be specific, resistant space heaters, the kind advertised everywhere this time of year, convert 1 kWh of electricity to 3412 BTUs of heat. The only difference between the many types of electric resistance heaters being offered is in the timing and distribution of those BTUs – some use “toaster” wire and an electric fan to force convection almost immediately, some heat ceramic or oil to radiate more slowly over time, and others use “proprietary, scientific fool’s-gold” to do I-don’t-know-what, but in every case you add 3412 BTUs to the space for every kWh you purchase.
Where electric resistant space heaters may make sense (the type is a personal preference) is when you can heat a small space instead of the whole house. Adding a little heat to the baby's bedroom can be a good idea. Heating a small room where you work all day and keeping the main furnace off is usually a good deal economically. Also, please consider a wood or pellet stove. Whether an electric space heater is a good deal environmentally is a more difficult question to answer – see Marvelous Electricity, Ah but the Cost.
The most cost effective electric heaters are geothermal heat pumps (GHP). These mechanical marvels do not “create” heat; they work by moving heat from the ground to the house in the winter (Heating) and from the house to the ground in the summer (Cooling). A typical GHP today moves 3 – 4 times more heat into the house than it consumes in electricity (Coefficient of Performance, COP = 3 to 4). Using an average COP of 3.5, an 80% efficient distribution system and average electric cost of $0.145, means it costs $15.18 for a GHP to deliver a million BTUs. If you have access to natural gas, this is not probably not a good investment due to the higher installation costs, but if you are choosing between oil, propane or electric (over 40% in NY) it can be a great investment, especially considering there is a 30% Federal Income Tax Credit available – see http://www.dsireusa.org/ .
Air source heat pumps are considerably more efficient than resistant electric heaters but somewhat less efficient than geothermal heat pumps throughout the heating season. They too move heat, but from the air instead of the ground. They are challenged by the little “heat” in air in our winter days and nights, but can be a very cost effective solution in the spring and fall and can also contribute in the winter months.
This is a quick overview. I plan to provide more details about geothermal heat pumps and other heating systems over the next couple of months. Before you make any heating investments or decisions please contact a reputable heating contractor that offers choices (heat pumps and other types of heating systems) to help you sort out your options, depending on your house, your costs and your goals. Also, remember it is always better to conserve a BTU than to create one!
Dan Gibson is the Reporter and Chief Coordinator of Our Energy Independence Community (http://www.OEIC.us). Previously he was a participating contractor in NYSERDA’s Home Performance program and a rater in the New York ENERGY STAR Home program. He is currently building a 100% Solar Home. He can be reached at DanG@OEIC.us