Sized, vented, tested
Furnace Installation and Replacement for Ontario Homes
A furnace that suits your home starts with a load calculation, not a guess. We review sizing, venting, gas supply and ductwork, then test everything at start-up. A quote follows a site review.
- ScopeFurnace replacement and new installs
- SizingLoad calculation, never a rule of thumb
- QuoteFollows a site review
Serving the GTA and nearby OntarioScope
What a furnace replacement scope covers
- Heat loss and load calculation to set the right furnace capacity (BTU/h output)
- Burner staging choice (single-stage, two-stage or modulating) for heat output, with the ECM blower and ductwork reviewed as a separate decision
- Venting review: PVC intake and exhaust runs, plus chimney or liner condition
- Gas supply check: line size, shut-off valve, sediment trap and connections
- Ductwork compatibility: return air size, supply balance and static pressure
- Pairing with a humidifier, air conditioner or heat pump (hybrid or dual-fuel)
- Thermostat compatibility and wiring for staged or modulating equipment
- Start-up checks, combustion safety review and old-unit removal as set out in your quote
Process
From first visit to a safe first start
Every job starts with a conversation and a look at the equipment. You see the options in plain language before anything is booked.
- 1
Site review and load calculation
We look at heat loss, insulation, windows, the existing ducts and the current furnace. Capacity comes from a load calculation, not a square-foot rule or the BTU label on the old unit. Oversized furnaces short cycle, and undersized ones struggle in a cold snap.
- 2
Choose the equipment
We explain burner staging (single-stage, two-stage or modulating) and, as a separate choice, the blower type (standard or ECM variable-speed) in plain terms. Pricing varies with equipment, venting, ductwork, installation complexity and warranty options; a quote follows a site review.
- 3
Venting, gas and duct work
We confirm intake and exhaust routing, the condensate drain, gas line capacity and any duct changes the new airflow needs. Gas and electrical work is done by licensed and qualified professionals or trade partners, depending on scope.
- 4
Start-up checks
After the install we test ignition, flame signal, temperature rise, airflow, safety controls and condensate drainage. Gas pressure is checked where applicable, and every vent joint is inspected.
- 5
Combustion safety review and handover
We review combustion safety with you, including working CO alarms, then walk through the thermostat, filter changes and annual maintenance. Manufacturer warranty terms apply; we explain them and help with product registration.
Interactive
Furnace efficiency
Compare furnace efficiency ratings. AFUE is the share of fuel turned into heat over a season.
Ratings are published by manufacturers; real use depends on sizing, ducts and settings.
In pictures
What this work looks like
Kelvin job photo
Kelvin job photo
Kelvin job photoPhotos from Kelvin Mechanical jobs in the GTA and nearby Ontario.
Good to know
Burner staging and blower type: two separate choices
Single-stage
The burner runs at one setting, either on or off. It is simple and proven, and it suits compact homes with steady loads. Expect more temperature swing between cycles.
Two-stage
Low fire handles most days and high fire covers the coldest ones. Longer, gentler cycles usually mean steadier room temperatures and quieter operation, especially with a variable-speed blower.
Modulating
Output adjusts in small steps to match the heat loss at that moment. It is often paired with a communicating thermostat and an ECM blower. Ducts must handle low-speed airflow well, so a duct review matters.
ECM blower and ductwork
ECM blowers adjust speed and typically draw less power at low speed than older motors. They cannot fix an undersized return or restrictive ducts, so we measure static pressure before choosing equipment.
Pairing with AC, a heat pump or a humidifier
A furnace replacement is the right time to match an AC coil, add a humidifier or plan a hybrid system with a heat pump. Ontario incentive programs change and may not cover a furnace on its own, so check rebate eligibility first. Financing, warranty and extended coverage are separate things; see financing options.
Ontario notes
Furnace replacement in Ontario: what to know first
Sizing for a real Ontario winter
A furnace has to cope with the coldest stretch of the year, but it should not be oversized for the rest. A load calculation looks at insulation, windows, air leakage and layout. Past upgrades matter too, since added insulation or new windows can lower the heat needed compared with what the old furnace was sized for.
Venting and chimney realities
Modern condensing furnaces use plastic intake and exhaust pipes through a wall or the roof, and they drain acidic condensate. Older furnaces used a chimney. Changing the venting can affect other appliances sharing the flue, so we review the whole setup, along with clearances and where the terminations sit relative to snow.
Permits and regulated gas work
Gas work is regulated in Ontario, and permit requirements for furnace replacement differ by municipality. Rules change, so we confirm what applies before work. Kelvin Mechanical works with licensed and qualified professionals and trade partners, depending on the project scope. Ask any contractor who arranges permits and inspections.
Timing your replacement
Demand for furnace work rises in the first cold weeks of fall and during deep cold snaps, and equipment availability can tighten. A replacement planned in late summer or early fall gives you more room to compare options, review ducts and decide on extras such as a humidifier or a hybrid heat pump.
Equipment we install and service
Brand names and logos belong to their owners. Availability depends on the product line and region.
Customer reviews
What customers say
Wonderful service fast efficient and cost effective they installed my furnace and did a very good job
Kelvin Mechanical installed our tankless and Keeprite furnace all in one day. Super fast and clean work. really happy with the job they did, def recommend.
Had a great experience with Kelvin Mechanical. They installed my heat pump and furnace in the same day, and I was seriously impressed with how efficient and professional the whole process was. Their pricing was way better than other quotes I got, and the quality of work exceeded expectations. The team showed up on time, looked professional, and worked like a well-coordinated crew. Zia did an excellent job leading the team — super knowledgeable and made sure everything was done right. I'd definitely recommend them if you're looking for solid HVAC work at a great price.
Five-star Google reviews, copied as written with shortened names. Read more reviews
Help centre
Questions about Furnace Installation
How do you size a new furnace?
With a heat loss and load calculation for the house, followed by a check of the duct system. Square footage alone does not tell you enough, and the old furnace may have been oversized from the start. We explain the reasoning behind the recommendation.
Is a two-stage or modulating furnace worth it?
It depends on your ductwork, comfort complaints and budget. Staged equipment can run longer at lower output, which often evens out room temperatures, but it only pays off with suitable ducts and thermostat control. We talk through both options before you decide.
How long does a furnace replacement take?
Timing varies with equipment availability, venting changes, gas line work, duct modifications, permits and site conditions. A like-for-like swap is quicker than a job that needs new venting or ductwork. We confirm the plan after the site review.
What affects furnace installation pricing?
Pricing varies with equipment, venting, ductwork, installation complexity and warranty options. Use Build My Quote to start the conversation, and a quote follows a site review.
Who does the gas and electrical work?
Kelvin Mechanical works with licensed and qualified professionals and trade partners, depending on the project scope. Permits and inspections are arranged where required.
How long does a furnace last in Ontario?
Many gas furnaces are expected to last somewhere in the range of 15 to 20 years, though it varies with the make, installation quality, maintenance and how hard the furnace works through an Ontario winter. Age is only one factor. Repeated repairs, heat exchanger concerns or rising safety worries weigh more. A site review gives you a straight answer.
Do I need a permit to replace a furnace in Ontario?
It depends on the municipality and the scope. Gas work is regulated in Ontario, and some cities require an HVAC or building permit for a furnace replacement while others handle it differently. Rules differ by municipality and change, so we confirm what applies in your city before work starts. Permits and inspections are arranged where required.
What size furnace does a 2,000 sq ft house need in Ontario?
There is no single number. Two 2,000 sq ft homes can need very different capacity depending on insulation, windows, air leakage, ceiling height and layout. A heat loss calculation sets the size, and we check the ducts and airflow as well. Many old furnaces were oversized, so copying the old BTU label is not a safe shortcut. Start with Build My Quote.
Can I replace my furnace in the middle of winter?
Yes. Furnaces often fail in cold weather, so winter replacements are routine. Timing depends on equipment availability, venting changes and permits. If you have no heat, call +1 905-407-7353 and we explain what we can offer, subject to availability. A planned replacement before winter gives you more time to compare options.
What happens to my chimney when I replace an old furnace?
Older furnaces often vent into a masonry chimney, while most new condensing furnaces vent through plastic pipe. If a gas water heater still uses that chimney, it may be left with a flue that is too large, which can cause poor venting. We review the chimney and the water heater venting as part of the replacement plan.
Should I replace my furnace with a heat pump or another gas furnace?
It depends on your ductwork, electrical service, energy rates and comfort goals. A new furnace is a familiar choice, a heat pump can heat and cool, and a hybrid keeps both. Rebate programs change and may not cover a furnace on its own. See heat pump installation and rebate basics.
Do I need to change my ductwork when I get a new furnace?
Not always, but new airflow can expose weak returns, undersized runs and leaks. Many homes built between the 1950s and 1990s have limited return air. We measure static pressure before choosing equipment and tell you what we find. Duct changes are only done with your approval.
What affects the cost of a new furnace installation in Ontario?
The unit's capacity and efficiency, the condition of the ductwork, venting changes, gas line and electrical needs, permits and access. A home visit lets the installer size the furnace and check these details before work is planned. Ask for the scope in writing so you can compare options like for like.
Where we do this work
Furnace Installation in Toronto, the GTA and Hamilton
Toronto Mississauga Brampton Vaughan Markham Oakville Burlington Hamilton All service areas Heating and cooling services
Quote and booking
Request: Furnace Installation
Share a few details and we will follow up. A written quote comes after a site review. There is no online checkout.
- City and service type help us route your request
- Urgency and property details let us prepare properly
- Optional equipment photos speed up repairs and replacements
Prefer to talk? +1 905-407-7353
Gas smell or carbon monoxide alarm? Leave the building and call 911 first. Do not use this form.