Hydronic Heating · Toronto & GTA
High-Efficiency Gas Boilers
Condensing gas boilers heat with water instead of forced air — quiet, even, and ideal for older Toronto homes with existing radiators, in-floor heat, or space limits that don't fit ductwork. Installed by TSSA G3 certified technicians.
$6,900 – $14,500 installed (GTA range)
What is a high-efficiency gas boiler?
A high-efficiency gas boiler is a hydronic heating appliance that burns natural gas to heat water, then circulates that hot water through radiators, baseboards, or in-floor tubing to warm your home. Unlike a forced-air furnace — which pushes heated air through ducts — a boiler moves heat quietly through pipes, delivering an even, radiant warmth without moving air (which is a big deal for allergy sufferers and anyone with dust sensitivity).
Modern condensing boilers run at 92–96% AFUE — meaning 92–96¢ of every dollar of gas becomes usable heat in your home, versus 60–70¢ on the older cast-iron boilers we routinely replace. That's a 30–40% energy-cost reduction on the same heat load, and the efficiency comes from recovering latent heat from the water vapour in exhaust before it leaves the vent.
Boilers are especially strong in three GTA scenarios: (1) older homes with existing hydronic (hot water) baseboards or cast-iron radiators you'd rather not rip out, (2) newer builds designed around in-floor radiant heat, (3) 'combi' installs where a single boiler serves both space heating and domestic hot water — replacing both furnace and water heater in one unit and one warranty.
| AFUE efficiency | 92 – 96% | Condensing designs (Viessmann, Weil-McLain, IBC) |
|---|---|---|
| Heat delivery | Hydronic (water) | Radiators, baseboards, in-floor, air-handler coils |
| Fuel | Natural gas | Propane conversion kits available |
| Combi capability | Optional | Serves domestic hot water + space heating |
| Warranty | 10-year heat exchanger typical | 5-year parts, 1-year labour |
| Lifespan | 20 – 30+ years | Longer than most furnaces on comparable maintenance |
When a gas boiler is the right call
Boilers aren't for every home — they excel in specific configurations. Here are the four scenarios where we recommend a boiler over a forced-air furnace.
You already have hydronic baseboards or radiators
Older Toronto homes with cast-iron radiators, hydronic baseboards, or in-floor tubing already have the distribution system a boiler needs — replacing the boiler is a targeted upgrade that leaves the rest of the heating system alone. Retrofitting the same house to forced air often means running ductwork through finished ceilings + drywall repair.
You care about even, radiant, quiet heat
Hydronic heat feels different from forced air — no fan noise, no dust movement, no drafts. Radiator or in-floor heat provides even warmth from the ground up, which many homeowners find more comfortable, particularly in homes with high ceilings or big open spaces.
You want one appliance for heat + hot water
A combi boiler serves both space heating (radiators or air-handler coil) and domestic hot water (like a tankless) from a single unit. That reduces installation footprint, simplifies gas + venting runs, and cuts the number of warranties and maintenance visits you're managing.
You're planning a heat pump + boiler hybrid
For homeowners looking to electrify heat but keep gas as a coldest-day backup, a hybrid heat-pump + boiler system uses the heat pump above roughly -8°C and switches to the gas boiler below. We install these regularly across the GTA — combining the efficiency of a heat pump with the reliability of gas on the coldest nights.
What we see go wrong on boiler installs
Oversizing to be 'safe'
The single most common boiler-install mistake we see is a boiler sized 25–40% too large for the home's actual heat load. Oversized boilers short-cycle — igniting, running for a few minutes, shutting off, and repeating — which drops efficiency, adds wear, and blows through the heat exchanger's cycle life prematurely. A proper Manual J load calculation is non-negotiable.
Skipping the hydraulic separation
Multi-zone systems and combi installs require hydraulic separation (a low-loss header or hydraulic separator) to keep primary and secondary loops from fighting each other. Skipping this shortcut saves $500 upfront but causes flow issues, uneven zone temperatures, and premature pump failure. We include it on every install where the manufacturer's manual calls for it.
Ignoring water chemistry
Boiler loop water needs to be treated — pH balanced, oxygen-scavenged, occasionally inhibited against corrosion. Filling a new boiler with raw municipal water and walking away leads to sediment, corrosion, and heat-exchanger failure inside 5–7 years. Every install we do includes water chemistry testing at commissioning and treatment where needed.
Combi undersized for peak DHW demand
Combi boilers serve both heat and hot water — but you only get one at a time in most designs. A combi sized to match a house's peak heat load may not have enough capacity for the peak domestic hot water load (multiple showers + dishwasher). We size combis against peak DHW demand, not average heating demand, and often recommend a small indirect tank buffer if peaks are high.
Why homeowners choose Energy Clean for gas boilers
- TSSA Registration #000214220
- Trane Comfort Specialist
- Home Depot Approved Contractor
- Baeumler Approved
- Google 4.9 · 308 verified reviews
Equipment we fit: Viessmann · Weil-McLain · IBC · Rinnai (combi) · NTI
Serving Woodbridge, Vaughan & the GTA since 2012
How our boiler install works
- 1
Free heat-load calculation
A senior advisor runs a Manual J heat load, maps existing distribution (radiators, baseboards, in-floor loops), and audits the venting + gas line. Written spec, no obligation.
- 2
Distribution audit
If you have existing hydronic distribution, we hydrostatic-test the piping to catch leaks before install, and map the zoning to make sure the new boiler and its controls match how your home actually needs heat delivered.
- 3
Written quote
Line-item quote covering boiler, controls, hydraulic separation, expansion tank, pumps, gas line upgrades (if needed), permits, warranty registration, and rebate filing.
- 4
Multi-day install
Typical boiler installs take 2–3 days — old boiler out, new one in, distribution reconfigured, water chemistry treated, and commissioned to manufacturer spec. Heat is off for one night; we coordinate around your schedule.
- 5
Commissioning + startup
Combustion analyzer report, flow-rate balancing, zone-by-zone temperature verification, and homeowner walkthrough of the controls and maintenance schedule.
- 6
Year 1 tune-up included
First-year annual maintenance is included on every install. Extended parts + labour warranty programs available.
Related products
Gas Boilers questions, answered
A gas furnace heats air and distributes it through ductwork via a blower. A gas boiler heats water and distributes it through pipes to radiators, baseboards, or in-floor tubing. Boilers deliver quieter, more even heat with no dust movement — better for allergy sufferers and homes with existing hydronic distribution. Furnaces are the more common install in newer builds because they share ductwork with central AC.
Modern condensing boilers achieve 92–96% AFUE — meaning up to 96¢ of every dollar of natural gas becomes usable heat in your home. That's a 30–40% efficiency improvement over the older mid-efficiency (82–85%) or cast-iron (60–70%) boilers we routinely replace across Toronto's older housing stock.
Yes — this is called a 'combi' boiler. A combi handles space heating (radiators, in-floor, or an air-handler coil) plus domestic hot water on demand from a single unit. It replaces both a boiler and a water heater with one appliance, one warranty, and one maintenance visit. Combis work best in medium-sized homes with moderate peak hot-water demand; very large homes with 4+ bathrooms often need a boiler + separate tankless setup.
Very often, yes. Homes built before ~1970 often already have cast-iron radiators or hydronic baseboards — replacing the boiler is a targeted upgrade that leaves the distribution system in place. That avoids the expense of retrofitting ductwork through finished ceilings, which for many Toronto homes with plaster walls and 9-foot ceilings can add $15,000–$25,000 to a forced-air conversion.
A properly-sized condensing gas boiler with annual maintenance and proper water chemistry lasts 20–30+ years. That's typically longer than a comparable forced-air furnace, largely because boilers cycle less frequently and don't have a moving blower motor as a wear point. The main lifespan variables are sizing (never oversize), water chemistry (treated + tested), and annual tune-ups.
Select high-efficiency condensing boilers qualify for the Ontario Home Renovation Savings program plus periodic Enbridge top-up rebates. Cold-climate heat-pump + boiler hybrid installs qualify for additional heat-pump-specific rebates. We track eligible models in real time and file the paperwork on your behalf as part of every install.
Get In Touch
Ready for even, quiet, radiant heat?
Book a free in-home boiler assessment — a senior advisor runs a load calc, audits distribution, and delivers a written quote in 24 hours.
905-417-4440 · Licensed & Insured · Free Estimates · Financing Available