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London’s winters put real demand on a furnace, and knowing the common warning signs — before you’re without heat — makes the difference between a simple fix and an emergency call. This page covers the furnace problems we see most often, what you can safely check yourself, and honest repair costs.
Common Furnace Problems in London, Ontario
Uneven heating. Certain rooms running warmer or colder than others usually points to a blower motor issue or a ductwork problem. If it’s persistent rather than a one-off, it’s worth a professional look.
Frequent cycling on and off. Often a faulty thermostat or a clogged air filter — both wear on the furnace and waste energy in the process. Regular maintenance catches most of this before it becomes a bigger issue.
Strange noises. Banging, rattling, or humming usually means a loose or worn component. These don’t fix themselves, and ignoring them tends to turn a small repair into a larger one.
Rising energy bills with no change in usage. A sign the furnace is working harder than it should — dirty filters, worn components, or a struggling blower motor are the usual causes.
A yellow pilot light instead of blue. This is a genuine safety issue, not a maintenance one — a yellow flame can mean incomplete combustion and carbon monoxide production. This needs a licensed technician immediately, not a DIY fix.
What You Can Check Yourself
Some furnace issues are safe to check before calling anyone:
- Replace the air filter if it’s visibly dirty — check monthly during heating season, replace every 1–3 months depending on usage.
- Check the thermostat is set correctly and functioning — a dead battery or miscalibration causes a surprising number of “no heat” calls.
- Clear the area around the furnace of stored items and debris — this isn’t just tidiness, it’s an airflow and fire-safety issue, and it also makes any technician visit faster.
What needs a professional, not a DIY attempt: a yellow pilot light, any suspected gas smell, ignition system faults, or anything involving the heat exchanger. These carry real safety risk if handled incorrectly.
What Does Furnace Repair Cost in London?
Rough 2026 Ontario ranges, so you know what you’re dealing with before a technician arrives:
- Minor repairs (thermostat, filter-related issues, minor sensor cleaning): roughly $150–$350
- Intermediate repairs (ignitor, control board, gas valve): roughly $300–$650
- Major repairs (blower motor, heat exchanger): roughly $400–$1,500+, depending on the component
- Diagnostic visit: typically $89–$120, often credited toward the repair if you proceed same-day
- Emergency or after-hours dispatch: commonly adds $100–$300
Most repairs take 1–3 hours; complex jobs like a motor replacement can take half a day. These are planning ranges — the number that matters is on a written quote after a technician has actually looked at your system.
Other Heating and Cooling Services
Beyond furnace repair, our licensed technicians handle:
- Air conditioning — installation, repair, and maintenance
- Heat pumps — installation, maintenance, and repair, including help choosing the right system for your home
- Boilers — routine maintenance, repairs, and new installations
Maintaining Your System
Schedule annual maintenance, ideally before winter — this is the single best way to catch a failing part before it becomes a no-heat emergency.
Clean ducts and vents periodically. Dirty ductwork restricts airflow and reduces system performance, and it’s an easy thing to neglect since it’s out of sight.
Serving London, Ontario
London is one of our regular Ontario service areas. We serve homes and businesses across the city, including established neighbourhoods like Old East Village, Byron, Masonville, Hyde Park, and Wortley Village.
As a licensed HVAC company, we hold the same TSSA and ESA licensing standards and the same 10-year parts and labour warranty on installations everywhere we work — London included.
When to Call for Emergency Furnace Repair
Call immediately if you smell gas, see a yellow pilot light, or have no heat during freezing temperatures. Contact us for furnace repair in London — our team offers 24/7 emergency service.
FAQs
Licensed HVAC technicians and companies like Dynamic Heating and Cooling provide furnace repair in London. Look for licensed, insured providers with 24/7 emergency availability and a track record of positive reviews.
Typically $150–$650 for most repairs, though major component failures like a heat exchanger can exceed $1,000. Simple fixes like a thermostat issue sit at the lower end; always request a detailed, written quote before work begins.
Look for licensed HVAC providers offering 24/7 emergency service with same-day availability — critical during Ontario's coldest stretches. Dynamic Heating and Cooling provides 24/7 emergency furnace repair for London.
Regular maintenance prevents breakdowns, improves efficiency, and extends furnace lifespan. In London's cold winters, it also reduces heating costs and lowers the risk of carbon monoxide issues from a poorly maintained system.
Check the thermostat setting and battery, replace a dirty filter, and confirm the power supply is intact. If the issue persists — no heat, strange noises, a yellow pilot light — stop troubleshooting and call a professional.
Annually, ideally before winter. A standard service includes cleaning components, checking airflow, and testing safety controls.
Often, yes — a modern high-efficiency furnace can meaningfully reduce heating costs compared to an older unit, and some models qualify for current rebate programs. If your furnace is over 15 years old, it's worth having efficiency compared directly rather than assuming the old unit is still cost-effective.
Most repairs take 1–3 hours. More involved jobs, like a motor replacement, may take half a day. Emergency calls are typically prioritized during winter.
Banging can indicate duct expansion; screeching or grinding often points to a belt or motor issue. Either way, it's worth a diagnostic visit before the underlying problem gets worse.