Short answer
A smart thermostat typically saves 5% to 10% on heating when you use it to lower the temperature at night and while you are out. With a heat pump, use smaller setbacks of 1 to 2 °C so the backup heat does not wipe out the savings.
Key takeaways
- Savings come from setbacks, so a smart thermostat only helps if it lowers the temperature when nobody needs the heat.
- Typical heating savings are 5% to 10%, more in leaky homes and long work days, less if you already set back by hand.
- With a furnace or boiler, setbacks of 3 to 4 °C at night and while away are typical and safe.
- With a heat pump, keep setbacks small and recover slowly to avoid triggering electric backup heat.
- Ontario's Home Renovation Savings Program offers $100 toward an eligible smart thermostat.
How much does a smart thermostat really save? In most Canadian homes, a smart thermostat used well typically cuts heating costs by about 5% to 10%. The device itself saves nothing. The savings come from setbacks, which means lowering the temperature at night and while the house is empty. If you already turn the heat down by hand every day, a smart model adds convenience more than savings.
Heat pumps change the rules. Deep setbacks can force a heat pump to use its electric backup heat to recover, and that can cancel the savings. With a heat pump, smaller setbacks of 1 to 2 °C usually work best.
Why setbacks save energy
Your home loses heat faster when the inside is much warmer than the outside. Lower the indoor temperature and the rate of heat loss drops. The house does not need extra energy to warm back up beyond what it saved, because the energy you avoided losing while it was cooler is greater than the energy needed to recover. A common rule of thumb is roughly 1% of heating energy saved for each degree Celsius of setback held for about eight hours a day. Treat that as a rough guide, since results depend on your home and climate.
Space heating is roughly 60% of the energy a typical Canadian home uses, so even a modest percentage cut adds up. Try your own setback schedule in the thermostat savings calculator.
Typical smart thermostat savings by setup
| Heating system | Suggested setback | Typical heating savings |
|---|---|---|
| Gas furnace or boiler | 3 to 4 °C at night and while away | 5% to 10% |
| Oil or propane furnace | 3 to 4 °C at night and while away | 5% to 10%, higher dollar value per degree |
| Air-source heat pump | 1 to 2 °C, slow recovery | 2% to 5% |
| Heat pump with gas backup (dual fuel) | 1 to 2 °C | Small, depends on changeover setting |
| Electric baseboards | 2 to 4 °C per room | 5% to 10% with line-voltage smart thermostats |
| In-floor radiant | Little or none | Low, the slab responds slowly |
Smaller setbacks with heat pumps
A cold-climate heat pump typically delivers 2.2 to 3.0 units of heat for every unit of electricity over a Canadian heating season. Electric backup strips deliver only one. When a heat pump has to recover from a deep setback on a cold morning, many systems call for the backup strips to speed things up. One hour of strip heat can cost more than you saved overnight.
To keep savings intact with a heat pump:
- Limit setbacks to about 1 to 2 °C, or skip them in the coldest weeks.
- Use a thermostat that supports heat pumps and has adaptive or slow recovery.
- Set the auxiliary heat lockout so backup only runs below a set outdoor temperature.
- For ductless mini-splits, use the unit's own schedule and keep changes small.
Our heat pumps in a Canadian winter guide explains backup heat in more detail, and the dual fuel heating guide covers changeover temperatures.
Do smart features add savings?
Features that help
- Geofencing and occupancy sensing. These set back the heat when everyone leaves, which catches days your schedule misses.
- Remote sensors. They balance comfort between rooms so you are less tempted to crank the setpoint.
- Usage reports. Seeing runtime helps you spot problems and adjust habits.
- Time-of-Use awareness. In Ontario, some homes on Time-of-Use or Ultra-Low Overnight plans can pre-heat or pre-cool during cheaper hours. See our Ontario price plans guide.
Features that matter less
Learning algorithms and voice control are convenient. They do not save much on their own if you already keep a sensible schedule.
Is a smart thermostat worth it?
A smart thermostat typically costs $150 to $350 installed. In a home with a gas furnace that spends $1,200 to $2,000 a year on heat, savings of 5% to 10% pay it back in a few years. Payback is faster with oil, propane or electric heat, and with Ontario's $100 smart thermostat incentive through the Home Renovation Savings Program. Check other provinces on our rebates page and confirm current amounts with your utility.
It is less likely to pay off if you work from home, keep a steady temperature by preference, or have in-floor radiant heat.
Simple setback schedule to start with
- Pick a comfortable daytime setpoint, such as 20 to 21 °C.
- Set back 3 to 4 °C (furnace) or 1 to 2 °C (heat pump) from 30 minutes before bed.
- Start recovery about 30 to 60 minutes before you wake.
- Apply the same setback during weekday hours when the house is empty.
- Review comfort after two weeks and adjust one setting at a time.
Frequently asked questions
How much can a smart thermostat save in Canada?
Typically 5% to 10% of heating costs when you use regular setbacks at night and while away. Savings are smaller if you already set back by hand or have a heat pump.
Should I turn down my heat pump at night?
Only by about 1 to 2 °C, with slow recovery. Deeper setbacks can trigger electric backup heat in the morning and cancel the savings.
Is it cheaper to leave the heat on all day or turn it down?
With a furnace or boiler, turning it down while you are out almost always saves energy. The house loses less heat while it is cooler, which outweighs the energy needed to warm back up.
Is there a smart thermostat rebate in Ontario?
Yes. The Home Renovation Savings Program offers $100 toward an eligible smart thermostat. Confirm current terms before buying.
What temperature should I set my thermostat to in winter?
Many households are comfortable at 20 to 21 °C when home and awake, and 16 to 18 °C overnight with a furnace. With a heat pump, keep the night setting within 1 to 2 °C of daytime.
Want numbers for your own home?
Use the thermostat setback savings with your province's prices and climate. It takes about two minutes.