This article was originally published on November 18, 2019

The short answer is you should use a space heater and keep the house at a lower temperature, since it's more efficient than heating the entire area of the house. However, if you’re concerned about your emissions, you can replace an oil or gas furnace with a heat pump which runs on electricity. You can also sign up to get your electricity from sources that are 100% renewable.

Megan Hall: Welcome to Possibly, where we take on huge problems like the future of our planet. And break them down into small questions with unexpected answers. I’m Megan Hall.

Today we have a question from a listener Barbara. She says, “I only need one room heated during the day. Should I use a space heater or heat the whole house?”

Molly Magid and Alina Kulman from our Possibly team looked into this question.. Welcome Molly and Alina!

Molly Magid: Hi Megan

Alina Kulman: Hello!

Megan Hall: So, should Barbara heat one room with a space heater or warm up her entire house?

Molly Magid: Well we visited Barbara at home to learn more.

Alina Kulman: First, she showed us her thermostat

Barbara: This is where the thermostat is. It's like all the way down to 55.

Molly Magid: After she sets the temperature at 55, she turns her space heater on.

Barbara: That’s my antiquated space heater. I have it plugged into a lamp timer so that it only goes on at certain times of the day

Alina Kulman: Barbara says she keeps the heater on for nine hours and then turns her thermostat up to 68 degrees after turning it off.

Megan Hall: And how many emissions does using the space heater create?

Molly Magid: Based on the type of space heater she uses and the amount of time it runs, we were able to calculate that it produces about 11 pounds of CO2 emissions.

Megan Hall: How does that compare to the emissions from heating the whole house at 68 degrees during the day?

Alina Kulman: Well, Barbara has an oil furnace. So, based on our rough calculations, if she heated the entire house, she’d produce about ten times the emissions of using the space heater.

Megan Hall: Wow! So, does that mean the space heater is more efficient than her oil furnace?

Molly Magid: Not really. That’s just because her house is about 10 times the size of the room she heats during the day.

Alina Kulman: Space heaters in general are less efficient than oil furnaces. If she heated her whole house with space heaters, that would actually produce more CO2 than heating the house with oil.

Megan Hall: So, are you saying an oil furnace is better than an electric heater?

Molly Magid: That’s a tricky question to answer. On the one hand, her electric space heater has to work a lot harder than the oil furnace to create the same amount of heat. So, it uses more energy.

Alina Kulman: Right now, this creates more emissions, because in Rhode Island her electricity comes from power plants that burn mostly natural gas.

Molly Magid: But if Barbara got her electricity from a renewable source like wind or solar power, the space heater would produce almost zero emissions.

Megan Hall: And that’s because sources of renewable electricity create almost no emissions?

Molly Magid: Exactly!

Megan Hall: So, what’s the answer to Barbara’s question? Should she use a space heater to heat one room during the day?

Alina Kulman: Yes. It’s definitely more efficient to heat one room instead of the whole house, even if you’re using an antique space heater.

Molly Magid: But, if Barbara is concerned about her emissions she could take a few more steps.

Alina Kulman: First, she could sign-up to get her electricity from sources that are 100% renewable. In Rhode Island, this option is available from a handful of companies that work directly with National Grid.

Molly Magid: Second, she could replace her oil furnace with something called an air source heat pump. Heat pumps run on electricity and are much more efficient than her old space heater or her oil furnace.

Alina Kulman: There are even rebates to help her make the switch.

Megan Hall: Great! Thanks Molly and Alina

That’s it for today. For more information or to ask a question about the way you recycle, use energy, or make any other choice that affects the planet, go to “the public’s radio dot org slash possibly”

Possibly is a co-production of the Institute at Brown for Environment and Society and the Public's Radio.


1. National Grid GreenUp Energy Providers