A furnace almost never dies in October. It dies at 5:40 a.m. on the coldest morning of the year, when the house is 54 degrees, the kids are awake, and every heating company in Pierce and King County has a full board. That timing is not bad luck — it's load. A cold snap is the first time all winter the furnace runs long, hard cycles back to back, and a marginal ignitor, a tired inducer motor, or a filter you forgot about finally gives up.
Here's the order of operations we'd give a neighbor. Free checks first, safety second, then the repair-or-replace math — with the honest note that the worst decision you can make in a cold snap is signing a $9,000 contract off one rushed quote.
Step one: the five-minute checklist
Do these before you call anyone. We'd rather you fix it yourself than pay us for a trip.
1. Thermostat
Set to HEAT, not OFF, not COOL, not AUTO-changeover confusion. Setpoint at least five degrees above the current room temperature. Fan on AUTO. If it's a battery thermostat with a blank or faded screen, put in fresh batteries — a dying battery pack is one of the most common "dead furnace" calls we get in the first hard freeze.
2. The breaker
Find the furnace breaker in the panel. If it's tripped, flip it fully OFF, then back ON. If it trips again immediately, stop. That's an electrical fault, not a reset problem, and repeatedly resetting it is how a small failure becomes an expensive one.
3. The gas supply
The shutoff valve on the gas line at the furnace should be parallel to the pipe. Also check whether your range and water heater still work — if nothing gas is working, the problem is upstream of your furnace and it's a call to the gas utility, not an HVAC company.
4. The air filter
Pull it. If light doesn't pass through it, that's your answer. A packed filter starves airflow, the heat exchanger overheats, and the high-limit switch shuts the burner down to protect the equipment. Homes near construction, with pets, or with crawlspace return leaks clog filters far faster than the box says.
5. The furnace door
There's a safety switch behind the front panel. If the door isn't seated square — often after a filter change — the furnace won't fire at all. Push it firmly closed and latch it.
If all five pass and the furnace still won't light, it's a real failure. Call furnace repair or reach us at (253) 785-4622. Service hours are Monday through Friday, 8 to 6, with same-week scheduling.
Step two: keep the house safe while you wait
This part matters more than people think, because the improvised heating is what actually hurts families — not the cold.
- Electric space heaters only, plugged straight into a wall outlet. No extension cords, no power strips. Three feet of clearance from bedding, curtains, and furniture. Don't leave one running in a room where nobody is awake.
- Never use a gas range, oven, charcoal grill, camp stove, or portable generator indoors or in an attached garage. These produce carbon monoxide. This is the single rule we'd underline twice.
- Test your CO alarms. If you don't have one on every sleeping level, buy one today. It's a $25 item and it is the difference between a cold night and a tragedy.
- Concentrate the heat. Close doors and vents to unused rooms, close blinds after dark, roll a towel against drafty door bottoms, and have everyone sleep on one floor.
- Protect the plumbing. If the house is heading toward the 40s, open cabinet doors under kitchen and bathroom sinks so warm air reaches supply lines, and let faucets on exterior walls drip. Frozen pipes turn a heating problem into a water-damage problem.
A note on the fireplace: a wood stove or an insert with a clean, inspected flue is legitimate supplemental heat. A decorative gas fireplace is not a heating system and shouldn't run unattended overnight.
Step three: understand what the technician is looking for
When a furnace quits in cold weather, the failure list is short and predictable. A diagnostic visit walks the sequence of operation — call for heat, inducer starts, pressure switch closes, ignitor glows, gas valve opens, flame sensor proves flame, blower engages — and finds where it stops.
| What failed | Why cold snaps expose it | Typical repair range |
|---|---|---|
| What failedHot surface ignitor | Why cold snaps expose itCracks after thousands of cycles | Typical repair rangeLow end of $150–$1,500 |
| What failedDirty flame sensor | Why cold snaps expose itCarbon buildup, furnace lights then quits | Typical repair rangeLow end |
| What failedPressure switch or blocked flue | Why cold snaps expose itLong run times, debris, or a bird nest | Typical repair rangeLow to mid |
| What failedInducer motor | Why cold snaps expose itBearings fail under sustained load | Typical repair rangeMid to high |
| What failedGas valve or control board | Why cold snaps expose itAge and heat cycling | Typical repair rangeHigh end |
| What failedCracked heat exchanger | Why cold snaps expose itFound during combustion inspection | Typical repair rangeSafety shutdown, not a repair |
Typical furnace repairs run $150 to $1,500 in standard markets and $175 to $1,800 in affluent ones. You should get the price before any work starts — no exceptions, no surprises on the invoice.
The one outcome that isn't a repair is a cracked heat exchanger. That's a combustion safety issue. If a technician red-tags the furnace, don't run it, and don't let anyone talk you into patching it.
Step four: the repair-or-replace call, cold-snap edition
Our standing rule: under 15 years old and the repair costs less than half a new system, repair it. Past 15 with a four-figure repair, replace it.
Cold weather doesn't change the math, but it does change the pressure. So separate the two decisions. If the furnace can be safely repaired today for a reasonable number, do that, get warm, and plan the replacement for spring when you can compare bids properly. If it can't — if it's red-tagged or the parts don't exist anymore — then you're replacing it now and here's the honest range:
| Path | Installed cost, standard markets | What you get |
|---|---|---|
| PathGas furnace replacement | Installed cost, standard markets$4,000 – $8,000 | What you getHeating only, 10-year parts and labor |
| PathFurnace + central AC together | Installed cost, standard markets$10,000 – $16,000 | What you getHeating and cooling, two systems |
| PathDucted heat pump | Installed cost, standard markets$12,000 – $18,000 | What you getHeating and cooling in one, rebate-eligible |
Affluent markets and larger homes run higher — $5,000 to $10,000 for a furnace, $13,800 to $21,600 for a ducted heat pump.
The gap between a furnace swap and a heat pump is narrower than most people assume once cooling enters the picture, and the heat pump is the only path on that table that can qualify for a local utility rebate. The amount depends on the utility that bills your meter, what you're replacing, and the efficiency of what goes in. Programs change and pay only through their own contractor networks, so we confirm what your utility actually pays before we quote and handle the paperwork. The federal 25C tax credit ended December 31, 2025 — no 2026 install qualifies, and any bid implying otherwise deserves a second look. If you want the full comparison, we laid it out in heat pump vs. gas furnace in Western Washington.
What stops this from happening again
Cold-snap failures are overwhelmingly maintenance failures in disguise. Three habits prevent most of them:
- Change the filter on a schedule, not when you remember. Every 60 to 90 days for a 1-inch filter, more often with pets.
- Get a tune-up in early fall, before the first hard freeze — that's when a weak ignitor or a marginal pressure switch gets caught on a Tuesday afternoon instead of a Sunday at dawn.
- Replace on your timeline. A dead furnace in January means one quote, no comparison shopping, and whatever equipment is on the truck. A planned replacement in March means a real Manual J load calculation, Good/Better/Best options, and a rebate filed correctly.
We're heat pump specialists, but we install and repair gas furnaces too, and we'll tell you when the repair is the right call. Every installation carries a 10-year parts and labor warranty, permits are pulled on every job, and most replacements are done in one day.
Cold house right now?
Run the five-minute checklist, make the house safe, then call us at (253) 785-4622 or request an estimate. Varsity Heating and Cooling is owner-operated out of Federal Way and serves 45 cities across King, Pierce, Thurston, and Kitsap counties — Washington contractor license VARSIHC766RJ.