Home Energy Myths: 12 Common Beliefs Ontario Homeowners Should Drop

Home energy myths cost Ontario households money in two ways: people skip easy savings because they think they do not work, and they spend on upgrades or products that do less than promised. The most common include the belief that thermostat setbacks waste energy, that closing vents saves money, that some space heaters cost half as much to run, and that new windows are the best upgrade for any older house.

Below are 12 we hear often, what the evidence says, and what to do instead. For myths specific to heat pumps, see our separate post on heat pump myths in Ontario.

Home energy myths at a glance

Myth	Reality	What to do
Reheating after a setback uses more energy	A cooler home loses heat more slowly	Set back 2–3 °C overnight with a furnace or baseboards
Turning the thermostat way up heats faster	Most systems heat at a fixed rate	Set the temperature you actually want
Closing vents in unused rooms saves money	Can reduce airflow and efficiency	Close one or two at most; fix comfort issues properly
Some space heaters cost half as much to run	All plug-in heaters are about 100% efficient	Choose on safety and thermostat quality
Turning lights on and off wastes energy	Switching uses negligible energy	Turn lights off when you leave a room
Off means off	Standby loads are 5–10% of electricity	Use smart power bars on clusters of electronics
New windows are the best upgrade	Long payback on energy alone	Air seal and insulate the attic first
Bigger heating and cooling equipment is better	Oversizing hurts comfort and efficiency	Insist on a load calculation
Washing dishes by hand saves energy	A full, efficient dishwasher usually uses less hot water	Run full loads; skip pre-rinsing under hot water
Ceiling fans cool a room	They cool people	Turn fans off in empty rooms
Electric heat is 100% efficient, so it is as good as anything	Heat pumps deliver 2–3 times the heat per kWh	Compare cost per unit of heat, not efficiency alone
"The government sent me"	Programs do not sell door to door	Check programs yourself at official sites

Thermostat and heating myths

Myth 1: "It takes more energy to warm the house back up than you save"

For gas furnaces, boilers and electric baseboards, this is false. Heat loss depends on the difference between indoor and outdoor temperature. When the house is cooler overnight, it loses heat more slowly, and that saving is larger than the energy needed to recover in the morning. A 2–3 °C setback overnight and while away typically saves roughly 5–10% of heating energy.

Heat pumps are the main exception. A large setback can trigger electric resistance backup during recovery, which uses two to three times as much electricity per unit of heat. Heat pump owners should keep setbacks to 1–2 °C. See our post on the best thermostat temperature for winter.

Myth 2: "Turning the thermostat up high warms the house faster"

A furnace delivers heat at roughly the same rate whether you set 22 °C or 28 °C. Setting it higher only means it keeps running past the temperature you wanted. The same is true for air conditioners in summer.

Myth 3: "Closing vents in unused rooms saves money"

In a forced-air system, the furnace or heat pump is designed for a certain airflow. Closing many registers raises pressure in the ducts, pushes more air out through leaks, and can reduce efficiency or cause equipment problems, especially with heat pumps. Closing one or two is usually fine; closing half the house is not. With baseboards or ductless systems, turning down individual rooms works well because each zone is separate.

Myth 4: "This space heater can cut your heating bill in half"

All plug-in electric heaters, whether ceramic, oil-filled, infrared or fan-forced, convert electricity to heat at essentially 100%. A 1,500 W heater costs the same per hour at full power regardless of type. A space heater only saves money if it lets you turn the central heat down a lot, and in a gas-heated home that rarely happens. Our post on space heater cost in Ontario shows the math.

Myth 5: "Electric heat is 100% efficient, so it is the best"

Electric resistance heat is 100% efficient at turning electricity into heat, but a cold-climate heat pump typically delivers 2.5–3 units of heat per unit of electricity over a southern Ontario season. Gas furnaces are cheaper per unit of heat than resistance heat at current prices. Compare cost per unit of heat, not efficiency percentages alone.

Myth 6: "Bigger is better for furnaces and air conditioners"

Oversized systems short-cycle: they run in brief bursts, which wastes energy, wears out parts, causes temperature swings and, for air conditioners, removes less humidity. Many existing Ontario furnaces are larger than the home needs. A proper heat loss calculation often supports a smaller, cheaper unit.

Electricity and appliance myths

Myth 7: "Turning lights on and off uses more energy than leaving them on"

The surge when a light switches on is tiny, equivalent to a fraction of a second of normal use. With LEDs, which use about 75–85% less energy than incandescent bulbs and are not harmed by frequent switching, the rule is simple: turn lights off when you leave the room.

Myth 8: "If it is switched off, it is not using power"

Many devices draw power around the clock: TVs, game consoles, set-top boxes, chargers, printers, microwaves and anything with a clock or remote. These standby or "phantom" loads typically make up 5–10% of household electricity. A smart power bar on the TV or office setup is an easy fix. See our standby power guide.

Myth 9: "Hand-washing dishes uses less energy than a dishwasher"

It depends on habits, but a full load in a modern ENERGY STAR dishwasher typically uses less hot water than washing the same dishes by hand under a running tap. Run full loads, scrape rather than pre-rinse, and skip the heated dry.

Myth 10: "Ceiling fans cool the room"

Fans move air across your skin, which makes you feel cooler; they do not lower the room temperature. In fact, the motor adds a little heat. Use fans to raise the air conditioning setting by a degree or two, and turn them off when nobody is in the room.

Upgrade and sales myths

Myth 11: "New windows are the first thing to upgrade"

Windows matter for comfort and condensation, and replacing failed or single-glazed windows can be worthwhile. But on energy savings alone, new windows usually take decades to pay back. In most older Ontario homes, air sealing and bringing the attic from R-12 to R-20 up toward R-50 to R-60 deliver more savings for far less money. A home energy assessment with a blower door test shows where your house actually leaks.

Similarly, solar panels can work well in Ontario, including in winter, but they are not usually the first or cheapest step for a household focused on cutting bills.

Myth 12: "This salesperson is from the government program"

Ontario's Home Renovation Savings Program, delivered by Save on Energy and Enbridge Gas, works through participating contractors that homeowners choose. Utilities and government programs do not send salespeople door to door to sell furnaces, water heaters or air conditioners, and Ontario has banned unsolicited door-to-door contracts for those products since 1 March 2018. If someone claims to represent a program, end the conversation and check details yourself at saveonenergy.ca (opens in a new tab) or ontario.ca (opens in a new tab). See our guide to door-to-door energy scams.

Tip: A quick way to test any energy claim is to ask, "What does it do to my kWh or m³?" If the seller cannot answer with a number and a source, treat the claim with caution.

Frequently asked questions

Does leaving the heat at one temperature all day save money?

Not with a gas furnace, boiler or electric baseboards. Lowering the temperature when you are asleep or away saves energy. Heat pumps are the exception, where small or no setbacks are usually best.

Do energy-saving devices that plug into an outlet really work?

Devices that claim to cut your bill simply by plugging into an outlet, often marketed as "power savers," do not reduce what an Ontario home is billed for. Residential bills charge for kWh used, and these devices do not reduce the energy your appliances need.

Is it cheaper to run appliances at night?

On Time-of-Use and Ultra-Low Overnight plans, yes. Off-peak electricity costs 9.1¢/kWh on TOU and 3.7¢ overnight on ULO, versus 18.9¢ and 37.7¢ at their peaks. On the Tiered plan, the time of day does not matter.

Are heat pumps really worth it in Ontario?

It depends on what you heat with now and your home. They usually save a lot compared with electric baseboards, oil or propane; compared with gas, running costs are often similar. See our heat pump myths post for details.