Quick answer
No, do not use your oven to heat your house. A gas oven or range is unvented, so running it for hours lets carbon monoxide and nitrogen dioxide build up in a closed house. An electric oven makes no fumes but is a fire and burn hazard, and it was not built to run with the door open. Use a certified electric space heater in one closed room and book an emergency repair.
You should not use your oven to heat your house when the furnace is out, whether the oven is gas or electric. The temptation is real at 2 a.m. with the house at 14 °C and falling, and the oven is right there. The reasons against it are specific, and so are the alternatives that work.
A gas oven has no vent, and that is the whole problem
A furnace, a water heater and a sealed fireplace all send their combustion gases outdoors through a vent. A gas range does not. Everything its burners produce, including carbon monoxide, nitrogen dioxide and a lot of water vapour, is released into the kitchen, on the assumption that cooking is short and a range hood is running.
Heating a house breaks both assumptions. An oven with its door open never reaches its set temperature, so the burner fires without cycling off, for hours, in a house you have closed up tight against the cold. Carbon monoxide has no smell and builds while people sleep. Nitrogen dioxide irritates the lungs and is hardest on children and anyone with asthma.
A power outage makes it worse, not better. The range hood is dead, any plug-in carbon monoxide alarm without a battery backup is dead, and the stovetop burners people light with a match have no thermostat at all. Rural homes cooking on propane face the same chemistry.
Electric ovens, barbecues, camp stoves and patio heaters
- Electric oven: no combustion gases, but an open oven door at knee height is a burn hazard for children and pets, the elements and controls were not designed for continuous open-door running, and anything left nearby can ignite. It also heats one end of the kitchen and little else.
- Charcoal or propane barbecue: produces large amounts of carbon monoxide. Never indoors, and never in an attached garage, even with the door up.
- Camp stove or lantern: built for open air. Same carbon monoxide risk in a far smaller package.
- Patio heater: an outdoor appliance with a cylinder that does not belong in a house.
- Clothes dryer run with the vent hose pulled off: fills the house with lint and moisture, and with combustion gas if the dryer is gas-fired.
Safer ways to stay warm until the furnace is fixed
- A CSA-certified electric space heater, or one carrying a cUL or ETL mark, plugged straight into a wall outlet. A 1,500-watt heater draws about 12.5 amps, most of what a 15-amp circuit can carry, so it gets a circuit to itself: no power bars, no extension cords, nothing else running on that breaker.
- A sealed, direct-vent gas fireplace. It vents outdoors, and many light without household power.
- One room, closed off. Pick a room with few outside walls, shut the door, roll a towel against the gap underneath, and put the heater and the people there.
- A municipal warming centre. Cities in our area open them during extreme cold; your municipality's website or information line lists the locations.
- An emergency repair call. Most no-heat calls end with a part replaced the same visit, and the oven question never comes up again.
Space heaters have their own rules, especially overnight; they are set out in whether it is safe to run a space heater overnight. If you are considering a propane unit instead, read whether a propane heater is safe indoors first.
When to leave the house instead
Use a simple rule: if you cannot keep one room comfortable with safe heat, and there is an infant, an older adult or someone unwell in the house, go to family, a hotel or a warming centre and deal with the furnace by phone. Before you go, open the cabinet doors under sinks on outside walls and leave a tap trickling. A cold house is a plumbing risk long before it is anything else.
What an emergency furnace call costs compared with improvising
- Diagnostic visit: $90–$150, folded into the repair if you proceed.
- Most furnace fixes, such as an igniter, flame sensor or capacitor: $150–$450.
- After-hours, weekend and holiday calls: ZK Mechanical does not add a surcharge.
People reach for the oven because they expect a night call to be expensive or slow to arrange. Check the easy things first with our list of what to do when the heat stops working at night: thermostat batteries, the furnace switch, the filter and the breaker fix a real share of no-heat nights. If those do not bring it back, ZK Mechanical's 24/7 emergency service line is (647) 801-1252, and non-urgent requests can go through the contact form. Other cold-night questions are collected under emergency answers.