Radiant Floor Heating · GTA
Boilers Built for Warm, Silent In-Floor Heating
Our in-floor heating boilers are high-efficiency condensing units designed to run at the lower water temperatures radiant floors need — for even, draft-free comfort from the ground up.
- TSSA-licensed gas work
- Heat-loss based sizing
- 20+ years in the GTA
A perfect match
Why Boilers and In-Floor Heat Belong Together
Low-temperature efficiency
Radiant floors run on cooler water, which lets a condensing boiler capture more heat from its exhaust.
Even, cozy comfort
Heat rises gently from the whole floor, with no cold spots, no drafts and no blowing dust.
Quiet and invisible
No vents, registers or radiators on the wall — just warm floors and more usable space.
The science, simply
Radiant Floors Need Lower Water Temperatures
In-floor radiant heat
Typical supply water temperature for radiant floors. Cooler return water keeps a condensing boiler in its most efficient range.
Radiators & air handlers
Typical supply temperature for cast-iron radiators, baseboards and hydronic air handlers.
Have both? We use a mixing valve or separate zones so each part of your home gets the right water temperature.
Where it works
Radiant Heat for Every Part of Your Home
Basement slabs
Turn a cold concrete floor into a warm living space.
Bathrooms & kitchens
Warm tile underfoot, all winter long.
Whole-home radiant
Primary heat for new builds and major renos.
Garages & workshops
Steady heat without blowing dust around.
Snow-melt systems
Driveways and walkways, sized with a larger boiler.
Mixed systems
Radiators upstairs, in-floor heat below — one boiler.
Engineered, not just installed
Everything Your Radiant System Needs
A great in-floor system is more than the boiler. We design the zones, controls and piping so every room heats evenly and the boiler runs efficiently.
Manifold with zone valves
Individual zone control and easy maintenance.
Mixing valve
Delivers lower floor temperatures alongside higher-temp zones.
Low-loss header
Balances flow in larger multi-zone systems.
Zone controller
Separate thermostats for each area of your home.
Outdoor sensor
Adjusts water temperature to the weather.
Oxygen-barrier PEX
Protects the system from oxygen corrosion.
Recommended boilers
In-Floor Heating Boilers We Recommend
Final sizing always comes from a heat-loss calculation for your home.
Most popular for radiant
Rinnai IP120S
Ideal for larger homes and whole-home radiant heat.
Radiant + hot water
Rinnai IP120199C Combi
One unit for radiant floors and on-demand hot water.
Large & snow melt
Rinnai IP200S
For large homes, snow-melt systems and multi-unit buildings.
Smaller loads
Navien NHB Series
Right-sized options for basements, additions and smaller radiant systems.
How it works
Your Radiant Heating Project in 4 Steps
Heat-loss calculation
We measure what each space needs, including floor coverings and insulation.
System design
We plan zones, the manifold, mixing and controls around your layout.
Install & commission
Our TSSA-licensed team installs the boiler and balances every loop.
Warranty & support
One year of free labour from 4Most, plus manufacturer coverage.
In-Floor Heating Questions
Straight answers about boilers for radiant in-floor heating.
Can I add in-floor heating to my existing boiler system?
Often, yes. If your boiler also feeds radiators or an air handler, we add a mixing valve or a separate zone so the floor loops get lower-temperature water. We check your boiler size and piping first.
Can a combi boiler run radiant floors?
Yes, for many homes. A combi such as the Rinnai IP120199C can supply radiant heat and on-demand hot water from one unit. Larger systems and snow-melt projects usually need a heat-only boiler.
Can in-floor heating be my only source of heat?
In many homes it can. It depends on your heat loss, insulation and floor coverings, which is why we size every system with a heat-loss calculation.
Why do condensing boilers suit radiant floors?
Radiant floors use cooler water, so the water returning to the boiler is cooler too. That lets a condensing boiler recover more heat from its exhaust and run more efficiently.
What maintenance does a boiler need?
Very little. These units are solid and usually last 15 to 20 years, and they hardly need major service before the 15-year mark. A yearly clean and tune-up is ideal, and our maintenance plans start from $12.99. Without a plan, have a certified technician check the unit at least every 5 years.
How does the warranty work?
4Most gives you one year of free labour on any installation issue or repair. Most boiler manufacturers cover parts for 5 years and the heat exchanger, the most expensive part, for 15 years. After the first year, if you need service, you pay for the service call and the repair labour, but not for the part. We also offer extended labour warranties for 5 or 10 years.
Why isn't the installation price on the page?
Every radiant project is different. The price depends on the boiler, the number of zones, the controls and how much piping is needed, so we quote each home individually.
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