The CCHT twin house facility in Ottawa, Canada

Two weeks ago in this blog I tried to answer the question, Do compact fluorescent lights (CFLs) save energy overall? Even though CFLs contribute a lot less heat to a house in the winter, compared to incandescents, CFLs still save energy overall, even in places like Anchorage, Alaska. Thanks to the folks at the Canada Centre for Housing Technology (CCHT) who did the research to answer that question.

The Department of Energy, the Environmental Protection Agency, and others recommend that we set our thermostats at 68°F in the winter and 78°F in the summer. Some people are comfortable at home with these temperatures and some or not. So how can we save energy and still be comfortable?

Besides recommending that people replace their incandescent bulbs with CFLs, we at Home Energy also encourage people to turn their thermostats down when they are away from home during the winter, and to set them up when they are away from home in the summer. Both actions are supposed to save energy. But do they? It’s not really that clear. For example, if you set your thermostat at 60°F before you leave for work in the morning, and then set it at 68°F in the afternoon when you get back, does your furnace use more energy raising the temperature of your house from 60°F to 68°F, than it saves by having the temperature at 60°F all day?

Once again the Canadians have come up with an answer. Marianne Armstrong and her colleagues at CCHT used the twin house research facility to show that thermostat set backs in the winter and thermostat set forwards in the summer really do save energy.

In the research house where they set the thermostat back to 64°F at night and during work hours, from 72°F, it saved more than 10% on heating costs compared to the house that was set at 77°F all day and night. A 61°F setback saved more than 13%.

In the summer, a set forward to 77°F at night and during work hours from 72°F saved 11% on cooling costs. Now for the big winner: Setting the thermostat up to 75°F all day and all night saved 23% of cooling costs compared to the house set at 72°F. That’s a savings of about 8% for every degree adjustment.

If you lower your thermostat a few degrees when you are away from home this winter, or when you are asleep, you’ll save energy and money. If you set your thermostat up a few degrees when you are away from home or asleep this Indian Summer, you’ll save energy and money. And you won’t be uncomfortable.

Top Energy (and Money) Saving Thermostat Tactics 20 September,2015Jim Gunshinan


Jim Gunshinan

Jim Gunshinan is the editor of Home Energy, the magazine of sustainable home building and renovation.

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