Quick Answer
If your furnace stops working during a Chicago deep freeze, check the thermostat setting and batteries, the air filter, and the circuit breaker before assuming the worst. A surprising number of no-heat calls trace back to one of these three things rather than a failed furnace. If none of them fix it, or if you smell gas at any point, stop troubleshooting and call D's Air & Heating at 773-940-0965 right away. Extreme cold moves fast, and a no-heat home is not something to wait out overnight.
Why Furnaces Struggle Most During a Deep Freeze
Chicago winters put more demand on a furnace than almost any other condition it faces all year, and the coldest stretches are exactly when systems fail. A furnace that's been running fine on a normal 30-degree day can reveal a marginal problem the moment temperatures drop into single digits or below and the system has to run nearly nonstop to keep up. A weak capacitor, a dirty flame sensor, an aging igniter, a blower motor on its last legs, none of these might cause a noticeable issue in mild weather, but extreme cold turns marginal into broken very quickly.
This is why furnace failures cluster so heavily around the coldest days of the year rather than spreading evenly across the whole heating season. The equipment is being asked to work harder than usual right when a small issue becomes a big one, and it's also why HVAC companies across the city see call volume spike dramatically during a deep freeze. If you're dealing with a no-heat situation right now, you're far from alone, and there are a few things worth checking before you assume the furnace itself has failed.
Cold snaps in Chicago aren't unusual, but the timing of a furnace failure often is. Homeowners frequently report that their system worked fine the day before, then stopped entirely once temperatures dropped sharply overnight. That pattern is a strong signal that the furnace was already running close to its limit, and the sudden cold simply pushed it past the point where it could keep compensating.
What to Check Before You Call
Before assuming the worst, walk through these checks. They take only a few minutes and resolve a meaningful share of no-heat calls without needing a technician at all.
1. Your thermostat. Confirm it's set to "heat," not "cool" or "off," and that the target temperature is actually set above the current room temperature. It sounds obvious, but a thermostat bumped accidentally, especially in a household with kids or guests, is a more common cause than people expect. If it's a battery-powered thermostat, dead batteries are a common and easy-to-miss cause of a furnace that seems completely unresponsive. Many smart thermostats will display a low-battery warning, but not all of them do, so if the screen is blank or unresponsive, batteries are worth checking first.
2. Your air filter. A filter that's severely clogged can restrict airflow enough that the furnace overheats internally and shuts itself off as a safety measure, a built-in protection that keeps the heat exchanger from being damaged. If you can't remember the last time it was changed, that's a sign it's overdue. A filter should generally be replaced every one to three months during heavy use, and a deep freeze counts as heavy use.
3. Your circuit breaker. Furnaces run on standard household electricity even though they burn gas or run on other fuel to actually produce heat, and a tripped breaker will shut the whole system down just like it would any other appliance. Check your electrical panel for a breaker that's flipped to the middle position or fully to "off." If you find one tripped, switch it fully off and then back on, and see if the furnace starts responding.
4. Your pilot light or ignition system, if visible and safe to check. Some older furnaces have a standing pilot light that can go out, particularly after a strong draft or a power flicker. If yours has one and you can see it's out, don't attempt to relight it yourself unless you're confident in doing so safely and know the manufacturer's relighting instructions. Gas appliances are not the place to guess, and a pilot light that won't stay lit even after relighting often points to a bigger issue, like a failing thermocouple, that needs a technician.
5. Your outdoor vent or intake pipe, if your furnace has one. High-efficiency furnaces vent through a pipe on the exterior of the home, and heavy snow or ice can block it completely, which triggers a safety shutoff. If there's visible snow buildup or ice around an exterior vent pipe, that alone can be the entire problem, and clearing it may restore heat immediately.
If you've checked these five things and the furnace still isn't producing heat, or if you smell gas at any point, stop troubleshooting and call for help immediately. A gas smell is never something to investigate further on your own, leave the house if the smell is strong and call your gas utility's emergency line before calling anyone else.
When It's Time to Call a Technician
A no-heat call during a deep freeze is treated as the emergency it actually is, not something to leave for a convenient weekday. Certain symptoms point clearly to a problem that needs a technician rather than more troubleshooting on your end:
The furnace won't start at all, even after confirming the thermostat, filter, and breaker are fine. It's blowing air but the air is cold, which usually points to an ignition or fuel supply issue rather than something you can fix by checking settings. It's making a loud banging, grinding, or screeching noise, which almost always signals a mechanical problem inside the unit. It keeps shutting off shortly after starting, a pattern called short cycling that points to an overheating or sensor issue. Or you notice a burning smell that isn't the normal, brief smell of dust burning off at the start of the heating season.
Any of these mean it's time to call 773-940-0965 rather than keep testing things yourself. A technician can diagnose the actual cause in a single visit, and getting that diagnosis quickly matters more in extreme cold than in any other season, since pipes can freeze and home temperatures can drop to unsafe levels faster than most people expect.
What Happens When You Call During a Cold Snap
Calling D's Air & Heating during a deep freeze puts you in touch with a real person who understands the urgency, not an automated queue. We treat no-heat calls during extreme cold as priority situations, since we know what's at stake beyond simple comfort: frozen pipes, unsafe temperatures for children, elderly family members, or pets, and the risk of a small problem becoming a much larger and more expensive one if the home goes without heat for an extended period. Our EPA certified technicians arrive ready to diagnose the actual issue rather than guess, and as an authorized Lennox dealer, also authorized for Carrier and Green equipment, any parts or repairs are backed by real manufacturer standards rather than a shortcut fix.
How to Reduce the Odds of This Happening Again
Once your heat is restored, the best way to avoid a repeat of a deep-freeze furnace failure is a professional inspection before the next cold snap, ideally every fall before the heating season really gets underway. A yearly tune-up catches the kind of marginal issues, a weakening capacitor, a dirty flame sensor, a blower motor starting to struggle, that don't cause problems in mild weather but become emergencies the moment real cold arrives.
Serving Chicago and These Communities
D's Air & Heating provides furnace repair and emergency no-heat service to Chicago and a wide service area across the surrounding suburbs and Northwest Indiana. Communities closest to our Monticello Ave location, where we can typically respond fastest, include Cicero, Berwyn, Oak Park, Forest Park, River Forest, Riverside, North Riverside, Maywood, Melrose Park, Bellwood, Broadview, Hillside, Westchester, Brookfield, La Grange, and La Grange Park.
We also regularly serve the western and near-western suburbs, including Elmhurst, Villa Park, Lombard, Glen Ellyn, Wheaton, Addison, Wood Dale, Itasca, Bensenville, Downers Grove, Lisle, Darien, Clarendon Hills, Hinsdale, Westmont, and Oak Brook.
To the north and northwest, we serve Elk Grove Village, Des Plaines, Park Ridge, Niles, Morton Grove, Skokie, Evanston, Wilmette, Glenview, Mount Prospect, and Arlington Heights.
To the south and southwest, our coverage includes Summit, Justice, Bridgeview, Burbank, Hickory Hills, Oak Lawn, Evergreen Park, Bedford Park, Alsip, Palos Hills, Palos Heights, Orland Park, Tinley Park, Midlothian, Robbins, Blue Island, Calumet Park, Riverdale, Dolton, South Holland, Harvey, Markham, Calumet City, and Lansing.
We also serve Northwest Indiana communities just across the state line, including East Chicago, Hammond, and Whiting.
If your community isn't listed above, call 773-940-0965 and we'll be glad to confirm whether we can help.
Furnace Deep Freeze FAQ
Is D's Air & Heating an authorized Lennox dealer? Yes. We're an authorized Lennox dealer, also authorized for Carrier and Green equipment, serving Chicago and the surrounding suburbs since 2009. That status means real manufacturer training behind every technician we send.
Why does my furnace stop working specifically when it's extremely cold outside? Extreme cold pushes a furnace to run longer and harder than it does on a mild day, which is often enough to expose a marginal issue that wasn't causing problems before, like a weakening capacitor or a dirty flame sensor. Call 773-940-0965 if yours has stopped working during a cold snap.
Is a furnace that keeps shutting off during a cold snap dangerous? It can point to an overheating or safety-shutoff issue rather than a simple fix, and it shouldn't be ignored, especially in extreme cold when going without heat for long isn't safe for a household. Call 773-940-0965 right away.
Do you offer emergency furnace repair near me? Yes. We treat no-heat calls as emergencies and serve Chicago along with dozens of surrounding suburbs, from Cicero and Oak Park to Evanston, Tinley Park, and Northwest Indiana. Call 773-940-0965 for the fastest response.
How can I prevent a furnace breakdown during the next deep freeze? A yearly furnace tune-up before the coldest months catches small issues before extreme cold turns them into a no-heat emergency. Ask about our maintenance agreement, which includes discounted, priority-scheduled service, when you call.
What should I do if I smell gas near my furnace? Leave the house immediately, don't operate any switches or appliances, and call your gas utility's emergency line before calling anyone else. This is the one furnace symptom that should never be treated as a wait-and-see situation.
Can extreme cold damage my furnace permanently if I don't get it fixed quickly? It can, especially if a struggling system keeps trying to run and short cycling repeatedly, which puts extra strain on components that are already failing. Getting a technician out quickly limits the damage and the eventual repair cost.
Is it normal for my furnace to run constantly during a deep freeze? Some increase in runtime is normal in extreme cold, since the system has to work harder to maintain the same indoor temperature. But a furnace that runs nonstop without ever reaching your thermostat's target temperature is worth having checked.
How quickly can D's Air & Heating respond to a no-heat emergency? We prioritize no-heat calls, especially during extreme cold, over routine scheduling. Call 773-940-0965 and we'll work to get a technician to you as quickly as possible.
What's the average cost to repair a furnace that stopped working in cold weather? Cost depends entirely on what's actually wrong, from a simple sensor cleaning to a part replacement, so an accurate number requires a technician's diagnosis. Call 773-940-0965 for a straightforward estimate once we know what's going on.
Have a furnace question we didn't cover? Call 773-940-0965 and we'll walk through it with you.
Don't freeze, call D's… No heat during a Chicago cold snap doesn't wait, and neither do we. Call 773-940-0965 now.
Call 773-940-0965
D's Air & Heating Inc. | 549 N Monticello Ave, Chicago, IL 60624 | 773-940-0965
