Q&A: Will using space heaters lower my heating bills?

I heat my home with natural gas but am considering using electric space heaters to try to cut costs this winter. Can portable heaters help me save, or are the claims I've seen just a lot of hype?

If your heater is equipped with a good thermostat and you do not heat the room to a warmer-than-normal temperature, you can save money by using an electric space heater in a room you’re in and keeping the rest of the house chillier. How much you’ll save depends on the room size relative to the rest of the house, how well separated the room is from others in your home, and how you use your space heater.

Like you, most Americans heat their homes with natural gas. Our experts say that if you were to use an electric space heater to warm one room to your normal room temperature and lower the temperature in the rest of the house, the amount you'd save would depend on how much heat that area requires relative to the rest of the house. If the heat required is less than half the total for your house,then you should be able to reduce your overall energy costs. Remember, on average, electricity in the U.S. is about twice as expensive as natural gas for the same amount of heating. So, for the same cost, you can heat only half the area.

Other ways to lower your heating costs, according to our in-house experts, include:
• Turning down your thermostat. Even lowering it 1°F reduces heating costs by about 3 percent.
• Improving the heat distribution of your central furnace instead of using pricier electricity to warm your home. If some rooms are too warm and others are too cold, the heating system is unbalanced and needs adjustment.
• Using a setback thermostat or turning off the space heater. If you go to bed at 11:00 p.m., set the temperature back at 10:00 p.m. or even earlier, or turn off the space heater well before you leave a room. Your house or the room won’t become uncomfortably cool immediately.
• Wearing on a sweater—or two. Mom was right: Extra clothing will keep you comfortable at a lower room temperature.

Finally, be safe when using a space heater. Electric space heaters cause an average of 3,000 fires each year in the U.S., often because of improper use, according to the National Fire Protection Association. Read the NFPA’s safety advice and our coverage of the risks associated with propane and kerosene heaters.

Essential information: “Save hundreds on energy costs” features expert advice on cutting your utility bills. See our recent reports on compact fluorescent lightbulbs, thermostats, and windows, all of which can help you lower energy consumption at and enhance the comfort of your home.

Comments

[Jonathan Beers]

I'd respectfully suggest consulting with another set of experts to get a better answer to this question. I'd suggest Oak Ridge Nat'l Lab in Tennessee, Advanced Energy Corp. in North Carolina or Home Energy Magazine (a side project of Lawrence Berekely Nat'l Lab). Your estimated savings from the "warm room" approach are overestimated in my opinion. Here's an email exchange I had on this topic w/ a researcher at a non-profit energy research and demo lab. (I'd want to get his permission before publishing his name and affiliation, can do so if you like).

Jonathan wrote to a researcher:
"We're getting a lot of questions about the economics of keeping one area warm w/ a secondary heating source and letting the rest of the house
get colder. We ask them about the efficiency of their primary heating source and the alternative they're considering.

For the following primary/secondary heating combos, I tell them it's probably not going to work: condensing furnace vs. a) open hearth product [even w/ glass doors] b) 78% or higher efficiency (AFUE) gas furnace vs. electric resistance heating.

Things get a little muddier when the secondary sources are wood stoves with a below market-rate source of wood, or sealed combustion gas fireplaces, or pellet stoves. (Or if they have lower efficiency furnaces.)

Reply from colleague:
"It comes down to (a) relative efficiencies and cost, (b) how much of the house they let get cool, and (c) how cool they let it get. Given that interior partitions are usually not insulated, my guess on (c) would be probably not cooler than
about 55F, which might then translate into 25% less primary heating for that part of the house. If that was say half the house, then you're looking
at about 12% savings."