Is an Electric Space Heater More Efficient Than Your Gas Furnace?
This time of year, I see a lot of ads for various types of electric space heaters. They all promise that you'll save money by using them rather than whatever other type of heat you have in your home. Some of them have famous—or formerly famous—people promoting them. Sometimes it's people who look like members of a small religious sect hawking these devices.
But are they correct when they say you'll save money by buying and using these small space heaters? The short answer is, probably not. All of these devices turn electricity into heat, which can be done at an efficiency of 100%. (This is true when we consider site energy only, not all the losses that occur between the power plant and your home. If we include those, the efficiency is closer to 30%.) If you have a natural gas furnace, its efficiency is probably in the 80% to 95% range.
But you can't compare just the efficiency of the energy used on site to make heat for your home. There are two factors you have to consider to determine if a small space heater will save you money:
- The cost of electricity versus the cost of natural gas
- The amount of space you're heating and how much heat you're adding to it
If you have a decent sized house and keep most of it fairly cool while moving a small space heater around to keep only yourself warm, then you might save money. The cost per Btu of heat for electric heat is generally more than double the cost per Btu for natural gas, especially with gas rates as low as they've been in recent years. It can be 3 to 5 times more than natural gas in some areas.
What that means is that you've got to use a lot less heat to save money with these electric space heaters. If you're into sacrificing comfort and convenience, this may work for you. The ads I see, however, all show happy homeowners being more comfortable than ever with these devices.
Using a small electric space heater is a strategy that can work, but be aware that the ads you see for EdenPURE, Living Pure, and Amish fireplaces don't tell you the whole story. They're really just expensive versions of the electric space heaters you can buy locally. See this review of the EdenPURE in the Mapawatt blog.
My advice is to check Consumer Reports if you're in the market for a space heater. And definitely don't go with an unvented gas space heater!
Photo by Paul.Carroll from flickr.com, used under a Creative Commons license.