What to Do When Your Heat Stops Furnace Repair Tips for London Ontario Residents
A furnace always seems to quit when the wind is up and the temperature has settled well below freezing. In London, Ontario, that usually means biting damp cold, drifting snow, and a house that loses heat faster than you expect. I have handled calls where a family went from comfortable to shivering in under an hour. The trick is not to panic. Most no-heat situations trace back to a handful of predictable issues, many of which you can safely check before you book an emergency call. And when it is time for a professional, knowing what to say and what to expect keeps the visit efficient and fair.
This guide blends homeowner triage with technician insight. It focuses on typical London homes heated by natural gas furnaces, usually high efficiency condensing units from 60,000 to 100,000 BTU, with PVC venting out the sidewall. If your home uses oil, electric baseboards, or a boiler, some details will differ, but the safety advice still applies.
The stakes on a cold night
There is comfort at stake, of course, but there is more. Pipes can freeze when indoor temperatures sit near or below 10 C for several hours, especially near exterior walls and in unfinished basements. Infants and elderly family members are more sensitive to cold. Even pets can run into trouble. Quick action, coupled with a little know how, can buy you time and sometimes restore heat without a service call.
How a modern gas furnace makes heat
It helps to picture the sequence. Your thermostat calls for heat, sending a signal to the control board. The inducer motor starts to pull air through the heat exchanger and out the vent, a pressure switch confirms adequate draft, then the igniter glows or sparks. Gas valves open, the burners light, flame is verified by a sensor, and only then does the main blower push warm air through the ductwork. A limit switch guards against overheating. In condensing furnaces, exhaust gases give up more heat, condensing into water that drains through a trap and tubing into a floor drain or condensate pump.
Any hiccup in that chain can stop the furnace. The good news, you can check several of these links without tools.
First, stay safe
If you smell rotten eggs, which is the odorant mercaptan added to natural gas, leave the house and call your gas utility or 911 from outside. Do not try to relight anything. Do not flip switches. In London, most homes are on Enbridge Gas. They have emergency response 24 hours a day.
Carbon monoxide is silent, with no smell. Every home with fuel burning appliances should have CO alarms near sleeping areas. If an alarm sounds, get everyone outside and call for help. Do not open windows to clear the alarm and then go back in. Let responders test. It is never worth the risk.
A rapid triage you can do in ten minutes
Check the thermostat. Confirm it is set to Heat, the setpoint is above room temperature, and the schedule or eco mode is not suppressing a call for heat. Replace batteries if it has them. Smart thermostats that recently lost Wi Fi or rebooted may have reverted to cooling only. Look at the furnace switch and breaker. There is usually a wall switch near the furnace that looks like a light switch. Make sure it is On. Then check your electrical panel for a tripped breaker. Reset once, firmly, if it has tripped. Inspect the intake and exhaust. In London, high efficiency furnaces often vent out a side wall a foot or two above grade. Wind driven snow can pack those pipes. Clear snow, frost, leaves, or nests. Shine a light to be sure you see open pipe, not ice. Replace or temporarily remove a clogged filter. A heavily plugged filter can cause overheating, then a limit switch trip that locks out the furnace. If the filter looks like a doormat, slide it out and try running without it for a short test. Put a clean filter in as soon as possible. Check the condensate path. Look for a blocked trap, kinked drain hose, or a condensate pump that is full and not running. A float switch in a backed up pump will stop the furnace to prevent a leak.
If the furnace still will not start, look through the viewing window on the blower door. Many control boards flash diagnostic codes. Count the blinks, short and long, then check the sticker on the blower door or the manual. Even if you do not decode it, sharing the pattern with a technician speeds diagnosis.
What you can fix without tools, and where to stop
Thermostats cause more service calls than most people expect. Battery powered models fade, and even a small voltage drop can confuse control logic. If you just swapped a thermostat, check that the wiring matches the old labels, and that a common wire is connected properly if the new model needs one. I have seen brand new smart thermostats pull the furnace into a short cycle because the installer faked a common wire with an adapter that later came loose.
Filters and vents are next. If the filter made a popping sound when you tried to remove it, or it collapsed and got partly sucked into the return, kill power and carefully pull all pieces out. Never run long without a filter. Dust on the blower wheel and secondary heat exchanger can cost you efficiency and cause future failures.
Condensate issues are rampant during cold snaps. Traps dry out in the fall if the furnace has not run much, then the first call for heat pulls air through and breaks the pressure switch sequence. Fill the trap with a bit of water. If you have a condensate pump, plug it into another outlet to test. If it still does not run and the reservoir is full, do not force it. Move a bucket under the line temporarily if possible, then call for service.
Intake and exhaust blockages are often visible. Clearing a frozen cap with a hair dryer or moving snow away is fair game. Do not chip or hammer at PVC. If there is ice inside the pipe beyond reach, that points to a drainage or slope problem that needs a technician.
Flame sensors and hot surface igniters are fragile. If you suspect one is fouled, resist the urge to sand it with emery cloth. A dirty flame rod needs gentle cleaning with a Scotch Brite pad or replacement. An igniter can crack if touched with bare hands. Both are quick repairs for a pro and affordable compared with a second visit after a DIY mishap.
Older furnaces with standing pilots are rare now, but they exist in some pre 1990 homes. If the pilot is out, follow the lighting instructions exactly. If it will not stay lit, the thermocouple may be failing, or the pilot orifice is dirty. At that point, stop and book service.
When to call a professional, and what to expect
There is a point where trial and error becomes false economy. Persistent lockouts, repeated breaker trips, or any smell of overheating call for a licensed technician. In Ontario, gas work must be performed by someone registered with the Technical Standards and Safety Authority. Ask the company to confirm their TSSA registration. For electrical work beyond simple cord and plug items, an ESA licensed electrician may be needed.
In London, a standard weekday diagnostic call typically runs around 120 to 180 CAD. After hours and holidays often start around 200 to 350 CAD. Parts vary, but common items give a sense of scale. A hot surface igniter might be 120 to 300 installed, a flame sensor 80 to 180, a pressure switch 180 to 350, a control board 400 to 900, and a variable speed blower motor 600 to 1,500 depending on the model. A cracked heat exchanger is serious and usually means replacement, not repair.
Good technicians do three things well. They verify power and thermostat signals, they test safeties and sensors with a meter instead of guessing, and they document readings in and out, such as temperature rise across the heat exchanger and static pressure in the ducts. Ask what failed and why. A pressure switch that does not close might be failing, or it might be telling the truth about a blocked drain or vent. Fix the cause, not just the symptom.
Keeping the house livable while you wait
Most London homes have a basement, which buys time because heat rises and the main floor cools slower than the walls suggest. Close blinds and drapes, especially on the windward side. Move a small space heater into the room where people will gather, but keep a meter of clearance all around and never run a heater unattended or overnight. If you have a wood or gas fireplace, remember it often draws warm air out of the house while burning. Use it for comfort, then close the damper, if safe and designed to be closed, once the fire is out and the unit has cooled.
Water lines near exterior walls are the first to freeze. Open cabinet doors under sinks to let room air reach the pipes. In an urgent case, trickle cold water at far sinks to keep lines moving. That wastes water, but it is cheaper than a burst pipe. If temperatures dip into the negative teens overnight, move aquariums or sensitive plants away from cold glass and drafts. Small actions prevent big damage.
Common culprits in London homes
Snow packed vents are at the top of the list after lake effect storms. I have arrived to find intake elbows packed solid six inches deep. Clearing the snow brings the furnace back to life in minutes. In many subdivisions, vent terminations are close to ground level because the original grade changed after landscaping. If your vents are consistently buried, consider raising the termination height. That is a job for a heating and cooling London Ontario contractor familiar with code clearances to windows and property lines.
Next is condensate backup, especially where the drain hose sags into a belly that holds water until it freezes near the wall. A simple reroute with proper slope toward a floor drain solves it. If you have a condensation pump, listen for a faint hum or buzz. A silent, full tank means the float switch has tripped and locked out the furnace.
Then comes the igniter. A brittle silicon carbide igniter can fracture after years of heating and cooling cycles. Many modern furnaces use silicon nitride igniters, which last longer but still fail. If you watch the sequence and never see a glow before the gas valve opens, that points to the igniter or the control board. If you see a glow and then no flame, the gas valve did not open, or there is no gas supply. Do not try to bypass anything. Call for service.
A clogged filter sets off a chain of overheating, nuisance limit trips, and short cycling. In homes with pets or renovation dust, a filter can load up in a month. Hold your filter to a light. If you cannot see light through it, it is done. Most London furnaces run well with a MERV 8 to 11 filter. Jumping to an ultra high MERV without resizing the return often chokes airflow and raises static pressure. I have seen blower wheels matted with drywall dust after a basement finishing project where the returns were left open. If you renovate, tape filters to every return, then change the main filter twice in short order.
A short word on codes and permits
New gas appliances and altered venting fall under CSA B149.1 code and local requirements. A reputable company handles permits and inspections where required, and they will leave you with documentation. Electrical connections to furnaces must meet the Ontario Electrical Code. Any new branch circuit or wiring change may require ESA notification. Ask. It protects you, and it helps with insurance later.
Carbon monoxide alarms are required near sleeping areas by the Ontario Building Code in most cases where a home contains a fuel burning appliance or an attached garage. Check batteries twice a year. Replace alarms at the end of their service life, generally five to seven years.
Preventive care that actually pays off
The cheapest insurance against a no heat call is a clean, properly sized filter, clear outdoor terminations, and an annual inspection that includes real measurements. A thorough tune up goes beyond a cursory vacuum. It checks temperature rise, verifies inducer and blower amperage, inspects the heat exchanger with mirrors or cameras where accessible, cleans the flame sensor properly, tests the pressure switch with a manometer, confirms condensate trap integrity, and checks the vent slope. Expect the technician to also look at duct static pressure. High static hints at undersized returns or restrictive grilles. Fixing that improves comfort room to room and reduces noise.
Pay attention to the condensate line route. If it runs along an exterior wall, insulate it or reroute. If your furnace drains into a pump shared with your air conditioner or humidifier, clean the pump each fall. A half cup of water with a splash of vinegar kept my own pump algae free for a season.
If your home has an HRV, keep its exterior hoods clear of snow and lint. A blocked HRV exhaust can depressurize parts of the house and mess with furnace combustion air in older setups. Clean or replace HRV core filters a couple of times a year.
Repair or replace, making the call in London
A well maintained gas furnace lasts about 15 to 20 years on average. Some run longer, but after 15 years, major parts become a reasonable risk. If your heat exchanger is cracked, if the unit has repeated expensive failures, or if you have comfort issues that trace back to single stage operation with poor ductwork, it may be time to talk about furnace installation.
For a typical detached home here, a quality high efficiency furnace with a variable speed ECM motor and two stage or modulating gas heating and cooling London valve usually lands around 3,800 to 7,500 CAD installed, depending on size, brand, and the duct and vent adjustments needed. High end models and complex installs can go higher. Ask for a proper heat load calculation. In Canada, the equivalent standard is CSA F280, which considers insulation, windows, and air leakage. Do not let anyone size your new furnace by the nameplate of the old one alone. Oversized furnaces short cycle, create temperature swings, and wear out parts faster.
Rebates and incentives change frequently. The Canada Greener Homes Grant intake paused in 2024, and the landscape has shifted. Enbridge Gas has offered programs under the Home Efficiency Rebate Plus banner, though terms and availability vary. Check Enbridge Gas and Natural Resources Canada websites for current details before you sign a contract. Reputable heating and cooling London Ontario companies will help you navigate the paperwork and timing.
If you proceed with furnace installation London Ontario homeowners should confirm the following with the contractor. They are TSSA registered, they pull permits or provide documentation as required, they include venting changes in the quoted price, and they will commission the unit. Commissioning includes setting blower speeds to achieve the correct temperature rise, verifying gas pressure, and confirming safe operation of all controls. Ask about warranty terms in writing. A ten year parts warranty is common from manufacturers when equipment is registered promptly, while labour coverage depends on the dealer.
What to tell the technician when you call
Make, model, and approximate age of the furnace, plus any error code blink patterns you observed. What happened before the failure. Any recent thermostat change, renovation dust, or power outage. What you have already checked. Thermostat mode, breaker, filter, vents, condensate. Where the furnace vents terminate and whether there was recent heavy snow or ice. Access details. Pets, driveway conditions, gate codes, and whether there is standing water near the floor drain.
These small details turn a vague complaint into a targeted visit. It also signals to the dispatcher whether to send a tech with a specific igniter, a control board variant, or a condensate pump.
Edge cases worth mentioning
Mobile or factory built homes use furnaces and ductwork that differ from conventional basements. Combustion air supply and clearances are not the same, and parts are sometimes proprietary. If that is your setup, mention it when you call. Likewise, homes with combined heating and cooling air handlers that incorporate an electric coil need a different diagnostic approach.
Smart thermostats draw power differently than old mercury stats. A missing or poor common wire can cause erratic behavior. If your furnace randomly shuts down when the Wi Fi router reboots, that is a clue. A simple common wire kit or a new cable with a proper C conductor often fixes it.
If your home has a whole home humidifier, a stuck open water valve can leak into the furnace cabinet or overload the shared condensate line. Look for water staining or mineral buildup around the humidifier pad. Replace pads annually and shut the water supply during cooling season.
Choosing a service company in a crowded market
When you search for furnace repair London Ontario, you will see a flood of options. Longevity and transparency matter more than logos. Look for companies that list their TSSA number, publish real pricing ranges, and have technicians who explain causes, not just parts. Ask whether they service your brand specifically and if their vans carry common parts for it.
For furnace installation, ask for at least two quotes with clear scope. One should include a two stage or modulating option, and the contractor should be willing to discuss duct changes, not just equipment swap outs. If every quote ignores that the back bedroom runs five degrees cooler than the rest of the house, keep asking until someone measures static pressure and offers a remedy.
Winter proofing so you do not lose heat again
Mark your intake and exhaust locations on a diagram taped inside the mechanical room. After a storm, it is easy to forget which hood is which. Keep a firm bristle brush and a small shovel near the back door for fast access. If your vents are close to a driveway, think about a low profile fence to keep drifting snow from building right against the termination.
Add a small surge protector to the furnace outlet if it is cord and plug connected. Power blips happen during heavy wind and ice, and control boards do not love voltage spikes. If your thermostat relies on batteries, stock a spare set in a labeled bag taped inside the panel near the furnace switch.
If your condensate drains to a floor drain that occasionally dries out and smells, pour a liter of water into it monthly during the heating season. Traps need water to block sewer gas, and a dry trap can also make some homeowners think they smell gas. Small, routine habits prevent a surprising number of service calls.
Final thoughts from the service floor
I have seen midnight calls fixed with a new 10 dollar set of thermostat batteries and Sunday afternoons where a family rode out the wait by clearing a snow packed intake. I have also seen furnaces condemned for heat exchanger cracks after years without inspection. The line between simple and serious is not always obvious to a homeowner, and that is fine. Your job in a no heat situation is to keep people safe, run a short, sensible triage, and call in help when the signs point to a deeper fault.
When you do call, give a clear picture and ask for the same in return. There are many solid professionals in heating and cooling London Ontario who will walk you through options, from a fast igniter swap to a thoughtful conversation about replacing an aging unit. If you choose to replace, take the time to size the system, tune the ductwork, and commission it right. Comfort is not just about BTUs, it is about even temperatures, quiet operation, and systems that start every time the wind whips across the city and you hear the inducer motor spin up like a promise.
For now, keep an eye on filters, vents, and drains. Those three alone cut your odds of an icy surprise by half. And if your thermostat seems a little too clever, remember the oldest fix in the book. Fresh batteries. It is not glamorous, but neither is shivering.
Hometown Heating and Cooling — Business Info (NAP)
Name: Hometown Heating and Cooling
Website: https://www.hometownhc.ca/
Email: [email protected]
Phone: (519) 425-0555
Service Area: London, Woodstock, and Ingersoll (Southwestern Ontario)
Ingersoll Location
Address: 113 Mutual St N, Ingersoll, ON N5C 1Z8
Map/listing URL: https://www.google.com/maps/place/Hometown+Heating+and+Cooling/@43.042608,-80.8860254,17z/data=!3m1!4b1!4m6!3m5!1s0x882e9bfee0d53bf3:0x9f78b1810f24ad23!8m2!3d43.0426041!4d-80.8834505!16s%2Fg%2F1tdgqgkq
Embed iframe:
London Location
Address: 45 Pacific Ct Unit #11, London, ON N5V 3N4
Map/listing URL: https://www.google.com/maps/place/Hometown+Heating+and+Cooling/@43.0088901,-81.1800363,17z/data=!4m6!3m5!1s0x882c1f2183b77adf:0x7511cc8383025dcb!8m2!3d43.0101465!4d-81.1752898!16s%2Fg%2F11fsm535_n
Embed iframe:
Hours:
Monday-Friday: 8:00AM-5:00PM
Saturday & Sunday: Closed
Open-location code (Plus Code): 2R6F+3V London, Ontario
Socials (canonical https URLs):
Facebook: https://www.facebook.com/Hometownhandc
Instagram: https://www.instagram.com/hometownhandc/
LinkedIn: https://www.linkedin.com/company/hometownhc/
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Hometown Heating and Cooling provides residential HVAC services across London, Woodstock, and Ingersoll in Southwestern Ontario.
Services include heating and cooling installation and repair, fireplace services, duct cleaning, ductless mini-splits, and gas line work (service scope varies by job).
The Ingersoll location is listed at 113 Mutual St N, Ingersoll, ON N5C 1Z8.
The London location is listed at 45 Pacific Ct Unit #11, London, ON N5V 3N4.
To contact Hometown Heating and Cooling, call (519) 425-0555 or email [email protected].
For directions, use the listings: https://www.google.com/maps/place/Hometown+Heating+and+Cooling/@43.042608,-80.8860254,17z/data=!3m1!4b1!4m6!3m5!1s0x882e9bfee0d53bf3:0x9f78b1810f24ad23!8m2!3d43.0426041!4d-80.8834505!16s%2Fg%2F1tdgqgkq and https://www.google.com/maps/place/Hometown+Heating+and+Cooling/@43.0088901,-81.1800363,17z/data=!4m6!3m5!1s0x882c1f2183b77adf:0x7511cc8383025dcb!8m2!3d43.0101465!4d-81.1752898!16s%2Fg%2F11fsm535_n
Popular Questions About Hometown Heating and Cooling
What areas does Hometown Heating and Cooling serve?
Hometown Heating and Cooling serves Southwestern Ontario, including London, Woodstock, and Ingersoll.
What services does Hometown Heating and Cooling provide?
Services listed include heating and air conditioning work, fireplaces, duct cleaning, ductless mini-splits, and gas line services (availability varies).
Where are Hometown Heating and Cooling locations?
Ingersoll: 113 Mutual St N, Ingersoll, ON N5C 1Z8.
London: 45 Pacific Ct Unit #11, London, ON N5V 3N4.
Do they offer emergency service?
The website indicates 24/7 emergency service for urgent HVAC situations.
How can I contact Hometown Heating and Cooling?
Phone: +1-519-425-0555
Email: [email protected]
Website: https://www.hometownhc.ca/
Facebook: https://www.facebook.com/Hometownhandc
Instagram: https://www.instagram.com/hometownhandc/
LinkedIn: https://www.linkedin.com/company/hometownhc/