Every fall it's the same: the furnace sits quiet from May to October, the first properly cold night arrives, and the thermostat clicks over to heat with nothing behind it. In Orléans that night isn't just uncomfortable. Ontario's Building Code sizes home heating here for a January design temperature of −26 °C, a degree colder than downtown Ottawa, so a furnace that's struggling in November won't get through February.
Before you call anyone, these checks take about ten minutes and fix more no-heat calls than you'd think.
First, is it the furnace or the street?
If the lights are out on your street, the furnace is out too. Even a gas furnace needs electricity to run its fan, igniter and controls. Hydro Ottawa posts outages on its online outage map. If the power is on but nothing gas-fired in the house works, the stove or the water heater included, the problem may be the gas supply. Call Enbridge Gas at 1-866-763-5427.
Ten minutes of checks
- Thermostat. Set it to Heat, a few degrees above the room temperature. If the screen is blank or faint, replace the batteries. Smart thermostats sometimes lose their settings after an update or a power blip.
- Furnace switch and breaker. The switch looks like a light switch and is usually on the wall beside the furnace or at the top of the basement stairs. It gets flipped off by accident more often than you'd think. Check the furnace breaker in the panel too.
- The furnace door. Most furnaces have a safety switch that keeps them off unless the front panel is closed tight. If someone changed the filter recently, push the panel firmly back into place.
- The filter. A badly clogged filter can make the furnace overheat and shut itself off. If it's grey and matted, replace it.
- The vent pipes outside. A high-efficiency furnace breathes through two white plastic pipes in a side wall. Leaves, a nest, or snow thrown by the snow blower can block them, and the furnace shuts down to stay safe. Enbridge Gas asks customers to brush snow off vents gently and never pile snow against them or the gas meter.
- Water by the furnace. High-efficiency furnaces make water as they run, and it drains through a small hose or a condensate pump. If that drain is plugged, or the pump has failed in a cold garage or crawlspace, the furnace stops. Water pooling around the base is the clue.
In the older parts of Orléans, like Blackburn Hamlet and the first streets of Convent Glen, some houses still have an older furnace that vents up the chimney rather than through plastic pipes. If yours is one of them, skip checks 5 and 6.
What not to do
- Don't keep resetting it. A furnace that locks out after a few tries is telling you something. Repeated resets can make a small problem bigger.
- Don't heat the house with the oven or a barbecue. Both can fill the house with carbon monoxide.
- Don't take panels off beyond the filter door. Behind them are the gas valve and the burners.
If you smell gas, or a CO alarm goes off
Stop checking. If you smell gas, leave the house and, once you're outside, call Enbridge Gas at 1-866-763-5427 or 911. If a carbon monoxide alarm goes off, get everyone out and call 911 from outside.
While you're thinking about it, check your alarms. Ontario already required a carbon monoxide alarm next to every sleeping area in any home with a fuel-burning appliance. Since January 1, 2026, you need one on every storey too, including the basement where the furnace is.
While you wait for the technician
If the house is cooling down, open the cabinet doors under sinks on outside walls so warm room air reaches the pipes, and let a tap drip if the house gets very cold. Close the curtains at night. If you use a space heater, keep it clear of anything that can burn and never leave it running in an empty room.
When to call
If the furnace still won't run after those checks, or it starts and quits, or it's making a noise it didn't make last winter, call us at (613) 801-3078. We're open 24 hours, and a certified technician will find the cause and tell you the price before any work starts.
And if this is the second fall in a row you've had this night, book a fall furnace check next September, before the first cold night instead of after it.