Calgary’s harsh winter temperatures put furnaces under heavy strain, making night failures common. Causes range from simple power or thermostat issues to more serious component failures. Understanding why your furnace dies helps you act safely and potentially restore heat until professional help arrives.
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Step‑by‑Step Checklist: What to Do Immediately If Your Furnace Stops at Night
When your furnace stops working overnight, quick action helps protect your family and prevent further damage.
- Check thermostat settings – Make sure your thermostat is set to heat and above room temperature.
- Inspect power sources – Verify the circuit breaker and furnace switch are on.
- Replace thermostat batteries if necessary.
- Check and replace the filter – A clogged filter can trigger safety shutdowns.
- Reset the furnace – Turn off power for 60 seconds, then back on.
- Inspect exterior vents – Look for ice or blockages that could restrict airflow.
These steps are temporary solutions; some problems may require professional repair.
Safe Ways to Stay Warm While You Wait
Until help arrives, keeping your family safe and warm is critical:
- Close doors to unused rooms to conserve heat.
- Use approved space heaters on dedicated outlets, away from combustibles.
- Layer clothing and blankets; consider relocating to the warmest areas of your home.
- Never use gas ovens or stoves for heat, this can lead to carbon monoxide poisoning.
Common Immediate Furnace Issues That Cause Night Failures
Some furnace problems are more likely to occur suddenly and at night. Recognizing these can help you understand the urgency.
Power or Electrical Faults
Tripped breakers, loose furnace switches, or thermostat misconfigurations can stop your furnace. Resetting breakers or checking thermostat power can sometimes restore temporary function.
Igniter & Flame Sensor Problems
Modern furnaces rely on electronic igniters and flame sensors, which can fail or become dirty, causing lockouts that prevent heat production.
Filter & Airflow Restrictions
Clogged filters or blocked vents restrict airflow, triggering safety shutdowns to prevent overheating and damage to the furnace.
Exterior Vent or Ice Blockage
High-efficiency units often have outdoor intake or exhaust pipes. Ice or snow blockages can force the furnace to shut down.
Typical Furnace Emergency Repair Costs in Calgary
| Repair / Issue | Typical Calgary Cost (CAD) |
| Filter change / thermostat battery | $0–$75 (DIY) / $100–$200 (service) |
| Igniter or flame sensor replacement | $250–$600 |
| Blower motor repairs | $500–$1,000 |
| Electrical diagnostics & reset | $200–$450 |
| Thermostat replacement | $150–$400 |
| Emergency after-hours callout | $150–$300 extra |
How to Avoid Midnight Furnace Failures in Calgary
Preventing night-time furnace failures requires routine maintenance and professional inspection before the winter season:
- Schedule annual furnace maintenance tune-ups. (Furnace Tune-Up & Maintenance Calgary)
- Change filters every 1–3 months during heavy use.
- Clear snow and ice from outdoor vents.
- Install smart thermostats to alert unusual operation. (Best Smart Thermostats for Calgary Furnaces)
- Have a professional check ductwork and airflow balance. (Sheet Metal Ducting Calgary)
These steps improve efficiency and reduce the risk of sudden night failures.
Stay Warm & Get Heating Help Fast in Calgary
A furnace failure at night is stressful and potentially dangerous. Taking safe first steps protects your home, while timely professional support restores comfort. Comfort Union provides 24/7 emergency furnace repair services across Calgary, handling everything from igniter replacements to complex electrical issues.
For trusted emergency furnace help, including professional diagnostics and quick repairs, learn more about Carrier’s HVAC emergency repair services.
Frequently Asked Questions
Can I reset my furnace myself?
Yes, turn off power at the breaker for about 60 seconds and turn it back on. This can fix minor lockouts, but repeated trips indicate a deeper issue that requires a licensed HVAC technician.
Is it safe to stay home with no heat?
Layer clothing and blankets, use approved space heaters safely, and close unused rooms. In extreme cold, consider temporary relocation to protect your family and pets from frostbite or hypothermia.
Why does my furnace stop only at night?
Nighttime failures often result from temperature changes, thermostat setbacks, blocked vents, ice on high-efficiency furnace pipes, or electrical components shutting off after repeated cycling in cold conditions.
How long will a repair take?
Simple issues like a blown fuse or filter replacement may take under an hour. Complex problems, including igniter or blower motor repairs, could require 2–4 hours depending on parts and accessibility.
Do emergency repairs cost more in Calgary?
Yes, after-hours, weekend, and holiday service calls usually include a premium fee. Costs also vary depending on the type of furnace issue, parts needed, and complexity of the repair.
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