Is it better to use a space heater or turn up your thermostat?
As winter recedes to spring, there are still days when the cold returns. You might wonder, does it make more sense to bump up the thermostat or find a space heater for comfort?
Choosing a space heater over central heat depends on a number of factors, including how many people you are trying to keep warm. While space heaters can be valuable tools for comfort – and can even be energy-efficient – there is a point of diminishing return.
Important factors to consider
If the desire is to heat an entire house, the central heat is more efficient, says Mikelann Scerbo, research manager for the Alliance to Save Energy, a bipartisan nonprofit coalition of business, government, environmental, and consumer leaders advancing federal energy efficiency policy.
A basic tenet is that electric space heaters are less efficient than HVAC systems. In most places, electricity is more expensive than natural gas, so a gas furnace is better for overall efficiency.
“Buying a space heater for every room would increase the electricity bill more than if you had just bumped up the thermostat,” Scerbo says.
For those looking to heat just one room, especially if the central heating system is very old and inadequate, a space heater could be a good fit.
“Ideally, you would be able to turn down the thermostat, letting the other rooms get a little cooler, while you are comfortable in the space-heated room,” Scerbo explains.
There is little research on just how low the thermostat can go when a space heater is taking up the slack, but the answer likely depends on how big the space is to be heated and how powerful the space heater is.
First, let’s look at the job the space heater must do.
If an entire family is home and in multiple rooms in the house, central heat will be the most efficient way to keep everyone comfortable. However, a single person at home all day can turn down the central heat and use a space heater for one room at a time, such as a home office.
The size of the room being heated by a space heater also matters. If the room you are choosing to heat with a space heater accounts for more than half of the size of your total house, you are better off with the central heat.
What’s the difference between types of space heaters?
If you have made the decision to consider a space heater, do your research. Not all space heaters are the same. Most importantly, electric space heaters are the only type that are safe to use indoors. Even electric space heaters can be a fire hazard. According to the U.S. Consumer Product Safety Commission, nearly 25,000 house fires a year are linked to space heaters.
There are two primary types of space heaters – radiant heaters and convection heaters. Radiant heaters emit infrared radiation that heats up whatever is closest to the unit. Convection heaters circulate warm air.
“Ideally, choose one with a thermostatically controlled heater to avoid overheating and wasting energy,” Scerbo advises. “Convection space heaters are better if you want to feel comfortable within an entire room, whereas radiant space heaters can work well if you only want to heat up a specific spot in a room.”
How much electricity will a space heater use?
When purchasing a new space heater, consider the amount of electricity it will consume. Some space heaters use as little as 400 watts while others use up to 1500 watts. A 750-watt electric heater uses 750 watts of power per hour regardless of whether it is a radiant, ceramic, oil-filled, bare metal coil, or another type. A 1500-watt heater will use twice the energy of a 750-watt heater and cost twice as much to operate.
A well-insulated home will be warmer using central heat or a space heater. If your home is not well insulated, some of the money you spend to stay warm is escaping through the cracks.
“The most efficient way to improve the comfort, health, and safety of the home is to properly insulate it and seal air leaks,” says Gwen Brown, communications director of the Interstate Renewable Energy Council, which promotes the adoption of clean energy and energy efficiency.
Brown says some energy customers may benefit from the federal Weatherization Assistance Program, or WAP, which helps low-income families lower heating costs.
Maximize the warmth you feel from a space heater by closing the door of any rooms with space heaters, allowing warm air to build up.
“Closing the door of the room would definitely help with a space heater, so long as the door doesn’t somehow obstruct the venting system,” Scerbo says.
Other tips to help keep warm
On sunny days, open curtains on south-facing windows to allow radiant heat from the sun.
Turn ceiling fans to spin clockwise in the winter to help push down the warm air, whether from a space heater or the central heat.
Finally, heat yourself. Wool socks, a sweater or a throw blanket will make it easier to lower the thermostat without sacrificing comfort.
Laura Williams-Tracy is a freelance writer who contributes regularly to American City Business Journals on a wide range of topics and covers business and finance issues for sectors of the commercial real estate industry.