Emergency HVAC Checklist: What to Do the Night Your Heat Goes Out
Heat failures have a habit of happening at the worst possible time — late at night, on the coldest night of the season. Here's a clear checklist to work through, in order, before and while you wait for help.
Step 1: Check the basics first
- Confirm the thermostat is set to "Heat" and the set temperature is actually above room temperature
- Check the thermostat's batteries or display — a dead battery can look like a system failure
- Check the breaker panel for a tripped furnace breaker
- For gas furnaces, confirm the gas supply valve is open and the pilot light (if applicable) is lit
Step 2: Rule out a gas leak
Step 3: Check the air filter
A severely clogged filter can cause some furnaces to shut down as a safety precaution. If it's visibly filthy, replace it and see if the system restarts.
Step 4: Call for emergency service
If the basics check out and you still have no heat, it's time to call. Have this information ready to speed up diagnosis:
- Furnace brand and approximate age, if known
- Any noises, smells, or warning lights you noticed before it stopped working
- Whether this has happened before
Step 5: Stay safe and warm while you wait
Never use a gas oven, stove, or grill to heat your home — this is a serious carbon monoxide risk.
Close off unused rooms to concentrate warmth in main living areas.
Layer blankets and clothing, and consider a safe, UL-listed space heater kept away from flammable materials and never left unattended.
Let faucets drip slightly if the cold is severe and prolonged, to reduce the risk of frozen pipes while the heat is out.
Keep pets and elderly household members in the warmest part of the home.
When to call a professional
If your household includes infants, elderly family members, or anyone with health conditions sensitive to cold, or if temperatures are set to drop significantly overnight, treat this as an emergency call rather than something to wait on until morning.
When to call a professional
Air 1 Mechanical offers 24/7 emergency heating service with no after-hours charge — call (703) 360-4357 any time, day or night.
