Setback Thermostats

Thermostats control heating and cooling appliances in houses. A setback thermostat gives the user the option of changing the temperature setting automatically at night and also during the workday when the occupants have left the house. A setback thermostat can help reduce overall household energy consumption.

A conventional thermostat simply regulates house heating at one temperature. For instance, in the winter, if you set the thermostat to 20°C (68°F), it will activate the heating system when the house temperature drops below 20°C and will shut the system off when the house air warms up past 20°C.

A setback thermostat contains an electronic clock. It can automatically turn down the temperature setting at night when you’re asleep, or during the day when you’re at work. It can also return the temperature to a more comfortable level before you wake up or arrive home from work. That way, you can have the energy savings of a lowered thermostat setting without the discomfort of having to wait for the house to heat up again.

The setback thermostat can also be used as a set-forward thermostat for an air conditioning system. It can allow the house to heat up when it’s unoccupied and return it to a comfortable temperature before occupants return from daytime activities.

Although this article deals with setback thermostats and forced-air heating systems generally, you can apply some of the advice to electric baseboards or to summer usage.

You can use a standard thermostat to set your house temperature lower during times when the house is unoccupied. This will lead to similar energy savings as with a setback thermostat, but without the convenience.

What’s a normal house temperature?

CMHC randomly surveyed Canadian households. Thermostat settings in the winter tend to be quite closely grouped around 20°C – 21°C (68°F – 70°F). Summer temperatures range much more widely, depending upon whether the house has air conditioning.

Where should I set the thermostat?

The more you reduce the thermostat setting, the greater the possibility for savings. Generally, a drop of 2°C (3.6°F) will lead to some savings and little risk. Some householders reduce temperatures 4°C – 6°C (7°F – 11°F). But, temperature differences this large create potential comfort and moisture problems.

Does setting back the temperature save energy?

Yes. Research from the Canadian Centre for Housing Technology shows that winter setbacks for the houses tested would result in heating cost savings of 5-15%. The highest savings came with a setback of 6°C (11°F). See CMHC’s Research Highlight: Effects of Thermostat Setting on Energy Consumption.

Savings for the summer were about the same, although simply raising the thermostat set point in the summer from 22°C (71°F) to 24°C (75°F) led to more significant savings than the set-forward strategy and also offered better indoor humidity control.

Note that these savings are for two airtight, well-insulated, unoccupied houses. The savings in your home may vary, but are likely to be in the same range.

To learn more about other sustainable technologies and practices that can improve the performance of your home as well as information on owning or buying a home, call Canada Mortgage and Housing Corporation (CMHC) at 1-800-668-26421-800-668-2642 or visit www.cmhc.ca.

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