Many homeowners wonder whether they should turn their furnace or air conditioner off completely when leaving the house. While it may seem like the best way to save energy, the answer is no. The smarter and often more cost-effective solution is to adjust your thermostat rather than shut your HVAC system off entirely. Lower the Temperature, Don't Turn It Off, recommended by HVAC professionals.
Keeping your home at a reduced temperature helps:
- Save energy and lower utility bills
- Maintain healthy airflow throughout your home
- Control indoor humidity
- Reduce wear and tear on your HVAC system
A good rule of thumb is to set your thermostat back by about 4–6°C (7–10°F) when you're away for several hours. Your home stays at a safe, consistent temperature, and your heating system won't have to work as hard to restore comfort when you return. Why turning your heat off completely can be risky during colder months can create several costly problems.
Frozen Pipes - When indoor temperatures fall below freezing, water inside pipes can freeze, expand, and burst. The result can be extensive water damage and expensive repairs, especially in homes with exposed pipes or poorly insulated areas.
Moisture, Condensation & Mold - A cold home also allows moisture to build up. As indoor temperatures drop, condensation can form on windows, walls, ceilings, and other surfaces. Over time, excess moisture can lead to: Mold and mildew growth, Wood rot, Damaged drywall and insulation, Poor indoor air quality. Modern, tightly sealed homes are especially susceptible because there is less natural air circulation.
Extra Wear on Your Heating System - Allowing your home to become extremely cold means your furnace or heat pump has to work much harder to bring the temperature back to a comfortable level. This prolonged recovery period increases system strain and may shorten the lifespan of important HVAC components.
What If you're away for several days or weeks? If you're leaving your home for an extended period, take these precautions:
- Set your thermostat between 10–13°C (50–55°F) to help prevent frozen pipes while minimizing energy use.
- Shut off the main water supply if you'll be away for an extended vacation to reduce the risk of water damage.
- Install a smart thermostat so you can monitor and adjust your home's temperature remotely. Smart thermostats can also help reduce heating and cooling costs by optimizing your HVAC schedule.
What About Air Conditioning?
During the summer, the same principle applies. Instead of turning your air conditioner off completely, increase the thermostat setting while you're away. This helps:
- Reduce energy consumption
- Control indoor humidity
- Protect hardwood floors, electronics, and furnishings from excessive heat and moisture
- Prevent your air conditioner from running continuously to cool an overheated home when you return
The Bottom Line
Whether it's winter or summer, don't turn your HVAC system off completely when you leave home. Adjusting your thermostat is a safer, more energy-efficient solution that protects your home, improves comfort, and reduces unnecessary strain on your heating and cooling equipment.
Need HVAC Advice or Maintenance in Ontario?
At Johns Home Comfort Heating and Cooling Ltd., we help homeowners throughout Caledon, Mississauga, Etobicoke, Vaughan, and the Greater Toronto Area keep their heating and cooling systems running efficiently year-round. Whether you need seasonal maintenance, furnace install, air conditioner repairs, or expert advice on improving your home's Indoor Air Quality, we're here to help.
Comfort Starts Here at 416-881-5425 to schedule your service.
