A cold house on a winter morning is no fun. Some causes are simple to fix yourself, so try these safe checks first. If the heat still does not come on, call a professional.
Five safe checks
- Thermostat. Make sure it is set to heat, the set temperature is above the room temperature, and the batteries are not flat.
- Power. Check that the furnace switch (it often looks like a light switch near the unit) is on and the breaker has not tripped.
- Air filter. A very dirty filter can make the furnace overheat and shut down. Replace it if it looks clogged.
- Vents. Make sure supply vents are open and not blocked by rugs or furniture.
- Outside vents. On high-efficiency furnaces, check that the pipes outside are not blocked by snow, ice or leaves.
When to stop and call
- You smell gas: leave the house straight away and call your gas utility’s emergency number from outside.
- The furnace makes loud banging, grinding or squealing noises.
- It keeps turning on and off, or the breaker trips again.
- Your carbon monoxide alarm sounds: get everyone outside and call emergency services.
When you call, tell us the make of your furnace if you know it, what you have already checked and anything unusual you have noticed. It helps the technician come prepared.