Top Tips for Furnace Installation in London Ontario

12 June 2026

Cold snaps in London, Ontario have a way of exposing the weak links in a home’s heating system. Between lake effect snow, damp fall stretches, and the odd spring frost, a furnace here works longer and harder than in many parts of the country. Getting a new unit installed is not just a Saturday purchase, it is a decision that affects comfort, air quality, utility costs, and safety for the next 15 to 20 winters. After years on job sites across Southwestern Ontario, I have seen tidy installations that ran like a well tuned truck, and I have seen hasty replacements that rattled, short cycled, and burned money. The difference almost always comes down to planning, sizing, and attention to details that you cannot see once the panels go back on.

This guide pulls together practical advice specific to furnace installation London Ontario homeowners can use, with a look at how heating and cooling London Ontario homes work as an integrated system. If you are weighing furnace repair versus replacement, I will touch on that too, because the best time to avoid an expensive sidestep is before you sign the work order.
Start with the right sizing method, not a rule of thumb
The question I hear first is some version of, What size furnace do I need? Someone inevitably offers a rule like 30 BTU per square foot. That is an easy way to overspend on equipment and undershoot comfort. In Canada, we size furnaces using CSA F280 heat loss calculations. That method accounts for local climate, insulation levels, window performance, air leakage, and how the house is built. In London, a 2,000 square foot, reasonably tight home with decent attic insulation may call for a 60,000 to 80,000 BTU input furnace, not the 100,000 BTU beasts common 20 years ago.

Oversizing sounds harmless until you live with it. Short cycling wears parts, robs you of even temperatures, and can leave rooms at the ends of duct runs chilly. Modern modulating and two stage furnaces soften the blow of oversizing, but they are not magic. Ask your contractor to show you their CSA F280 load report or an equivalent HRAI calculation. If you only see a quick glance at square footage, keep looking.
Understand stages, efficiency, and fans in plain terms
Sales brochures love acronyms. What matters is how the unit behaves in your house and on your gas bill.
Single stage, two stage, and modulating, compared Single stage furnaces run full tilt or not at all. They cost less up front, but in London’s shoulder seasons they cycle on and off more often. Expect wider temperature swings. Two stage units run at a lower output most of the time, then ramp to high on colder days. Quieter, steadier, and usually worth the small premium. Modulating furnaces vary output in small steps. They are the smoothest, often the quietest, and pair well with tight homes. In a drafty older house without duct fixes, you may not feel the full benefit.
AFUE tells you steady state efficiency as a percentage. Most replacements here land in the 95 to 98 percent AFUE range. On paper, 97 beats 95. In real life, duct losses, setup, and how you operate the system shape the bill as much as the label does. An ECM blower motor is a quiet workhorse. It ramps gently, uses less electricity, and plays nicely with air conditioning, heat pumps, and air cleaners.
The local code and permit picture
Ontario treats fuel burning appliances with the seriousness they deserve. Your installer should be licensed for gas work and pull the appropriate gas permit through the Technical Standards and Safety Authority. If electrical changes are required, such as adding an outlet for a condensate pump or running a new circuit for a humidifier, expect an Electrical Safety Authority notification of work. Swapping a furnace usually does not trigger a municipal building permit, but it still must meet the Ontario Building Code and gas code CSA B149. Reputable heating and cooling London Ontario companies handle this in the background and leave you copies of the paperwork.

A practical note about London’s winters. Condensing furnaces vent with PVC pipes that terminate outdoors. CSA B149 sets clearances from windows, doors, grade, and corners, and for good reason. I have answered too many no heat calls after a snow squall buried a low termination. Make sure the intake and exhaust terminate high enough, ideally above expected snow drift lines, and use proper screens and elbows to reduce wind driven issues.
Placement, ductwork, and the stuff you cannot see later
Furnace installation is not a drop in event. The furnace sits at one end of a system that must move air quietly and evenly. Most shortcomings hide in the supply plenum, return drop, filter rack, and transitions.

In basements with eight foot ceilings, we often need to rebuild the supply plenum to maintain a gentle transition angle and keep static pressure in check. Static pressure is the backpressure your blower fights. Target a total external static of 0.4 to 0.6 inches of water column unless the manufacturer allows more. If you never see a manometer come out during commissioning, you are guessing.

Return air matters as much as supply. Undersized return drops cause whistling, filter bowing, and high blower watt draw. A common upgrade is replacing a narrow return drop and 1 inch filter slot with a wide drop, a sealed filter rack, and a 4 inch media filter. A MERV 11 or 13 media filter strikes the right balance here. You get real particle removal without choking the blower. If you plan to add a high resistance accessory https://www.facebook.com/Hometownhandc/ https://www.facebook.com/Hometownhandc/ like an electronic air cleaner or UV kit, tell your installer early so they can design around it.

New high efficiency furnaces produce acidic condensate. Route the condensate line in rigid PVC or quality vinyl tubing with a visible trap. In many London basements, we discharge into a floor drain. Where that is not possible, add a condensate pump on a dedicated receptacle and consider a neutralizer kit to protect plumbing. Avoid long runs across the floor that invite trips or freeze near garage walls.
Duct sealing and airflow corrections that pay back
You can feel the difference when a home’s ductwork is tight and balanced. We usually find two or three percent leakage in new sheet metal work if it is sealed with foil tape or, better, mastic. In older homes with panned joist returns and makeshift takeoffs, leakage can hit 20 percent. That is heated air into wall cavities and unconditioned spaces. Ask for visible sealing at new joints and transitions, and expect at least basic balancing at the registers. Simple tweaks like slightly opening the basement return and reducing supply to rooms that run hot can even out temperatures without a zoning system.

When air conditioning or a heat pump shares the furnace blower, a cased coil sits above the furnace. That coil adds pressure drop. The installer must set blower speeds so you hit the furnace’s rated temperature rise in heating and the coil’s required airflow in cooling. Otherwise you end up with lukewarm supply temps in winter and a sweating coil that cannot keep up in July.
A short homeowner checklist before installation day Clear a path to the mechanical area and protect flooring on stairs and hallways, especially in wet or slushy weather. Identify where the thermostat wire, electrical supply, and any condensate drain will run. If outlets or drains are missing, plan for them in advance. Decide on filter type and location. A 4 inch media rack is easier on the blower and often fits with a small duct modification. Confirm vent termination locations outdoors. Walk the yard with the installer to avoid future planters, decks, or snow banks. Ask how they will verify setup. You want to hear about static pressure readings, gas manifold pressure, combustion analysis, and temperature rise.
That last point is not nitpicking. On a modulating furnace, gas valve calibration and fan tables matter. On a single or two stage unit, set the manifold pressure and verify temperature rise within the rating plate. Good installers take readings and tag the furnace with the results.
Real world pitfalls I see in London basements
London has a mix of 1960s bungalows, 1980s subdivision two stories, and plenty of older homes with stone basements. Each presents a different quirk.

In older homes with short returns and long supply runs, back rooms go cold. A right sized, two stage furnace helps because low fire runs longer and pushes air to those ends. Still, a couple of well placed return drops on the second floor do more than any high end furnace alone. If you are renovating, add those returns while walls are open.

In homes with shared laundry rooms, lint migrates. I have pulled filters that looked like felt blankets after two weeks. If a furnace lives near a dryer, keep the return low to the ground sealed tight and raise the filter slot off the floor to reduce lint draw. Consider a MERV 11 filter to avoid quick clogging, and clean the flame sensor more often. I have lost count of mid January no heat calls cured by a five minute flame sensor polish with emery cloth.

Lake effect snow creates another regular. On windy nights the intake pipe can suck snow and trip the pressure switch. I see this most with terminations under decks or too close to grade. A simple re termination with proper spacing and orientation ends those calls. It is far cheaper to correct on install day than at 2 a.m. When the house is 15 degrees.
Cost ranges and what drives them
Homeowners ask for exact numbers before anyone has stepped foot in the basement. I understand. A fair way to think about it in London is as a range shaped by size, staging, duct modifications, and accessory choices. A quality 95 to 97 percent AFUE furnace with a two stage gas valve and ECM motor, installed with minor ductwork and proper PVC venting, often lands in the 4,500 to 8,500 Canadian dollar range. Modulating models, tricky vent routes, extensive return air fixes, or adding a media filter rack can push higher. Pairing with a new air conditioner or heat pump changes the conversation because the coil, line set, and electrical work enter the picture.

Labour warranties vary. Ten year parts warranties are common with registration, but labour coverage can be anywhere from one to ten years depending on the company and plan. Ask what is covered, what is excluded, and how after hours calls are handled in a cold snap. When you are deciding between furnace repair London Ontario options and full replacement, weigh any major part costs against the age of the unit. Blower motors and control boards can buy you time on a midlife furnace. A cracked heat exchanger or repeated ignition failures on a 20 year old unit usually tip the scale to replacement.
Thermostats, zoning, and simple controls that make a difference
Smart thermostats have their place, but they are not a cure for duct imbalance. In most London homes, a good programmable thermostat placed on an interior wall away from supply registers is the right choice. If you choose a smart model, confirm it plays well with your specific furnace staging. Some need a common wire for stable power. In older houses, fishing a new thermostat cable during the installation day saves future headaches.

Zoning, where dampers control airflow to different parts of the house, can work in large or multi level homes. It also adds complexity and requires a furnace that can handle reduced airflow without overheating. An easier win in many cases is a continuous low speed circulation mode on the ECM blower. It mixes air quietly, evens out temperatures, and helps filtration without a huge electricity penalty.
Safety items that belong on every install
Natural gas furnaces are safe when installed correctly. That starts with proper gas line sizing and leak checks. If the home uses corrugated stainless steel tubing, make sure bonding meets the Ontario Electrical Code. Venting must maintain required clearances and slope back to the furnace so condensate returns to the drain, not to the siding.

Ontario requires carbon monoxide alarms near sleeping areas in most dwellings. Even if you already have one, test it and note its age. Many alarms expire after seven to ten years. Fresh air intakes and combustion air provisions should match the furnace type. Sealed combustion units pull air from outside through the intake, which is a blessing in tight homes. Keep those terminations clean and accessible. A quick brush after a storm can save a service call.
Commissioning, not just connecting
What happens after the last screw goes in separates a polished job from a rushed one. A proper commissioning routine in our climate includes:
Static pressure measurements across the filter and coil, and total external static to verify duct capacity and airflow settings are in range. Gas manifold pressure checks and, on modulating units, setup of the gas valve according to the manufacturer’s procedure. Combustion analysis at the flue to confirm oxygen, carbon dioxide, and carbon monoxide levels are where they should be. Temperature rise checks across the heat exchanger to ensure the furnace is neither starving for airflow nor blasting too hard. Control verification so the thermostat stages as expected and the blower ramps appropriately for heating and cooling.
I keep a simple tag on the furnace with these numbers. It gives the homeowner confidence and gives the next tech a baseline if a problem crops up later. That little card has spared many hours of guesswork.
Tuning the system to your home’s humidity and ventilation
London winters are not as dry as the Prairies, but indoor humidity still drops when furnaces run for hours. If hardwood floors gap and static shocks get out of hand, a bypass or fan powered humidifier can help. They are not plug and play. Poor install can introduce mold risks or mineral buildup. Use a proper water feed with backflow prevention, set a reasonable setpoint, and clean pads before each heating season.

Many newer homes here include an HRV for balanced ventilation. Coordinate HRV airflow with the furnace blower settings. If the HRV moves too much air without the furnace fan, some rooms get cold drafts. A simple control strategy is to run the furnace blower on low when the HRV is in continuous mode, or tie HRV operation to intermittent fan cycles.
When furnace repair is the smarter move
I am in the business of solving problems, not replacing equipment for its own sake. If your furnace is under 12 years old and has a single failed component like an inducer motor, hot surface igniter, or pressure switch, furnace repair is often the right call. Many of these repairs in London Ontario fall in the few hundred dollar range and can be handled same day from a stocked van. If heat exchanger cracks, repeated control board failures, or severe corrosion show up, that points to systemic issues like improper venting, drainage, or chronic overheating. At that point, replacement protects safety and stops the churn of breakdowns.

Anecdotally, the January after a heavy snow year brings a flood of no heat calls traced to blocked intakes or neglected filters. One night on the north side of the city, we cleared a choked intake elbow packed with crystalline snow and replaced a filter that looked like a sweater. The furnace fired immediately and the homeowner vowed to shovel a path to the vent after every storm. Simple habits prevent a lot of midnight visits.
Working with a heating and cooling company the right way
The best outcome comes from clear expectations. During your quotes, pay attention as much to the questions asked as to the numbers given. If a contractor spends most of their time asking about your comfort complaints, layout, filter preferences, and future cooling plans, you are on the right track. If everything revolves around a brand name and a price, keep pressing.

Expect a clean worksite, drop cloths, and safe handling of the old furnace and refrigerant coil if present. Ask where the old metal and cardboard go. Many of us recycle most of the scrap. Confirm how long the job will take. A straightforward replacement with minor duct changes usually lands in the 4 to 8 hour window. Complications like tight stairs, coil replacements, or long vent runs add time. Make sure someone walks you through filter changes, thermostat operation, and what to watch for on the vent terminations before they leave.
Rebates, financing, and timing your project
Incentive programs change, sometimes without much notice. Federal and provincial rebates related to heating efficiency, smart thermostats, or home energy upgrades have started and paused over the last few years. Before you commit, check current information from Enbridge Gas, the Independent Electricity System Operator, and the City of London for any programs that apply. Many require a pre installation energy audit or registration. The safest approach is to verify eligibility in writing and plan your schedule around any audit windows.

If you prefer to spread the cost, most established firms offer financing with clear terms. Read the fine print and calculate total cost compared to a cash price. The cheapest monthly payment is not always the best deal over the life of the loan.
Seasonal habits that protect your investment
A well installed furnace deserves basic care. Change or wash filters on schedule, usually every two to three months for 1 inch filters and every six to twelve months for 4 inch media filters, adjusted for pets and renovation dust. Keep the intake and exhaust clear of snow, leaves, and nests. Test your carbon monoxide alarms. If you have experienced nuisance lockouts, record the error codes. Most control boards flash them. That simple note speeds diagnosis.

An annual check by a qualified technician helps. I do not mean a cursory vacuum and a sticker. A meaningful visit includes cleaning the flame sensor, inspecting the drain trap, checking electrical connections, verifying temperature rise, confirming gas pressure, and ensuring combustion readings are in line. If your unit shares ductwork with a cooling coil, we also look at coil cleanliness and drain pans in spring.
Final thought from years in the field
Furnace installation is a craft. The equipment matters, but not nearly as much as the design and the hands that put it in. In London, where systems grind through long heating seasons and shrug off wet shoulder months, the small decisions add up. Proper sizing with CSA F280, thoughtful duct transitions, clear vent terminations above drifting snow, sealed filter racks, careful commissioning, and a homeowner who knows what to watch make the difference between a noisy gas hog and a quiet, efficient partner for the next decade.

If you are beginning the process, talk to two or three reputable heating and cooling London Ontario contractors. Ask them how they size, how they measure, and how they stand behind their work when the mercury falls. Whether you choose furnace repair or a full furnace installation, that conversation sets the tone for the winters ahead.

<h2>Hometown Heating and Cooling — Business Info (NAP)</h2>

Name: Hometown Heating and Cooling

Website: https://www.hometownhc.ca/ 
Email: sales@hometownhc.ca 
Phone: (519) 425-0555

Service Area: London, Woodstock, and Ingersoll (Southwestern Ontario)

<h3>Ingersoll Location</h3>
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 
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<h3>London Location</h3>
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 
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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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https://www.hometownhc.ca/

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 sales@hometownhc.ca. 
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

<h2>Popular Questions About Hometown Heating and Cooling</h2>

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 tel:+15194250555 
Email: sales@hometownhc.ca mailto:sales@hometownhc.ca 
Website: https://www.hometownhc.ca/ 
Facebook: https://www.facebook.com/Hometownhandc 
Instagram: https://www.instagram.com/hometownhandc/ 
LinkedIn: https://www.linkedin.com/company/hometownhc/

<h2>Landmarks Near London, Woodstock, and Ingersoll</h2>

1) Victoria Park (London) https://www.google.com/maps/search/?api=1&query=Victoria%20Park%20London%20Ontario 
2) Fanshawe College (London) https://www.google.com/maps/search/?api=1&query=Fanshawe%20College%20London%20Ontario 
3) Pittock Conservation Area (Woodstock) https://www.google.com/maps/search/?api=1&query=Pittock%20Conservation%20Area%20Woodstock%20Ontario 
4) Woodstock Art Gallery https://www.google.com/maps/search/?api=1&query=Woodstock%20Art%20Gallery%20Woodstock%20Ontario 
5) Ingersoll Cheese & Agricultural Museum https://www.google.com/maps/search/?api=1&query=Ingersoll%20Cheese%20%26%20Agricultural%20Museum%20Ingersoll%20Ontario 
6) Harris Park (London) https://www.google.com/maps/search/?api=1&query=Harris%20Park%20London%20Ontario