No heat in freezing weather — do these steps now
Call now — then work the list below while help is on the way
Repairs start the moment the call is made. Everything below this band is what you do while a contractor is en route.
📞 (888) 810-2291The 6 checks that restore most heat
Work them in order. Each takes seconds and fixes a real, common cause.
Thermostat
Set to HEAT, 3°F above room temp, fresh batteries. A dead cell or a schedule override stops the whole furnace.
Breaker + furnace switch
Reset the furnace breaker once. Then find the furnace's own shut-off switch — it looks like a light switch on or near the unit and gets bumped off during cleaning. This fixes more real cases than any other check.
Air filter
Hold it to a light. A filter clogged solid triggers the overheat shutdown that cuts the burners. Swap it and let the furnace cool.
Gas valve
The handle should be parallel to the gas pipe (open). If a utility crew recently worked the line, the meter valve may still be off.
Intake & exhaust pipes
High-efficiency furnaces vent through white PVC pipes out a side wall. Snow, ice, or leaves blocking either one locks the furnace out. Clear them — this is the winter-specific cause most people miss.
Pilot or ignition
Pre-2010 units have a standing pilot to relight per the panel steps; newer ones click to ignite. No click and no pilot after the checks above means an internal fault.
Heat restored? Book a tune-up before it happens again. Still dead, and the house isn't dangerously cold? Work the full diagnostic in furnace not turning on — that page carries the deeper fixes.
Protect the people
Order of priority: people, then pipes, then property. Warm the humans, not the whole house.
- One room strategy — pick the smallest room, ideally south-facing, close the door, and concentrate everyone and any safe heat there.
- Space heater, three rules — keep 3 feet of clearance from anything that burns, place it on a hard floor, and plug it directly into a wall outlet, never an extension cord (per CPSC guidance).
- Never the oven — a gas oven vents carbon monoxide indoors. It is not a heat source.
- Layers beat one big blanket — trapped air between layers insulates better; add a hat, since a lot of heat leaves through the head.
If the house is dropping into the 40s and you have an infant, an older adult, or anyone with a health condition, relocate them somewhere warm now.
Protect the pipes
Pipes are at risk once temperatures near them fall below about 20°F for several hours. Do these:
- Drip the faucets — a slow trickle on the farthest fixtures and any on exterior walls keeps water moving.
- Open cabinet doors under sinks so room air reaches the pipes.
- Close the garage and any exterior doors near plumbing.
- Find your main water shut-off now — before you need it in a hurry.
A burst pipe turns a $300 repair night into a $5,000+ water-damage claim. The drip is free insurance.
One winter note: the furnace's own condensate line can freeze too. If a high-efficiency furnace shows a pressure-switch or drain error, a frozen condensate line is the likely winter culprit — back to check 5 on the intake/exhaust.
Emergency visit tonight — or a morning call?
Call now
- Subzero or fast-dropping indoor temps
- Infants, older adults, or medical needs in the home
- Any gas smell or CO alarm
- Pipes already at risk of freezing
Can wait until morning
- Mild night, healthy adults only
- Safe space heat holding a room comfortable
- No gas or CO concern
- No plumbing at freeze risk
Premium honesty: after-hours visits run about 1.5–2× the daytime rate. If you're safe tonight, a morning call costs less — and we route that one just the same. If it's a confirmed emergency, see emergency furnace repair. Fee details on HVAC service call cost.
Emergency heat help is available 24/7 by calling (888) 810-2291 — the call routes to a licensed local contractor in your area.
Common questions
Will pipes freeze in one night without heat?
They can if indoor temperatures near exposed pipes drop below about 20°F and stay there for several hours — most common in unheated walls, crawlspaces, and against exterior walls. A slow faucet drip on the farthest fixtures is cheap insurance against a burst.
Is it safe to sleep in a house with no heat?
For healthy adults, a night in the 50s°F with layers and blankets is uncomfortable but generally safe. Infants, older adults, and anyone with a medical condition are far more vulnerable — if the house is dropping into the 40s, relocate them somewhere warm.
Do emergency HVAC visits cost more?
After-hours, weekend, and holiday visits typically run about 1.5–2× the standard fee. The call to reach a contractor through us costs nothing — the fee is the contractor's, charged at the visit. If the night is mild and you're safe, a morning call costs less.
Why did my furnace stop working in the middle of the night?
Overnight is when the furnace runs hardest, so a marginal part fails then. The most common overnight cause is an overheat or safety shutdown — a clogged filter or a blocked vent tripping the limit switch — followed by ignition faults. Work the first-10-minutes checks.
Can I run my gas oven for heat?
No. A gas oven vents combustion byproducts, including carbon monoxide, into your living space and is a genuine poisoning risk. Never use an oven or stovetop to heat a room — use safe space heaters and layers instead.