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Heating · HydronicRadiant Floor Heating Installation
Radiant floor heating installation means warm water circulating through PEX loops in or under the floor instead of hot air blowing from a register. We quote it as hydronic work — heat source, manifold, mixing valve, loops and controls — and it suits basement slabs, additions and bathroom floors far better than it suits a whole retrofitted house.
In-floor heat works because the floor itself becomes the radiator. Water at roughly 35–45°C is enough, versus the 70–80°C an old cast-iron radiator system wanted, and that low water temperature is exactly the range a modern condensing boiler is most efficient in. Comfort is different too: there is no air movement, no register noise, and the temperature gradient runs the right way — warm at your feet, slightly cooler at the ceiling. Radiant versus forced-air heating compares the two honestly, including where forced air wins.
There are three ways it gets installed, and they are not interchangeable. Loops tied to mesh and poured into a new slab give the best output and the slowest response — good for a basement or a garage floor, poor for a room you want warm in twenty minutes. Staple-up loops under an existing subfloor with heat-transfer plates work in a joist bay you can reach from below, which usually means a basement ceiling that is open or coming down. Electric mats under tile are the third option, and they are a bathroom-floor comfort product rather than a heating system; they are typically wired by the electrician on a tile job, so we will tell you when that is the right call rather than quoting hydronic for it.
Two details decide whether an in-floor project performs. The first is insulation under the slab: without rigid foam below and at the slab edge, a heated basement floor pushes a meaningful share of its output into ground that sits near 10°C year-round, and the fuel bill shows it. The second is the floor covering. Every layer above the loops adds resistance, so thick carpet with a foam underpad, or a floating floor over a thick underlay, can throttle a system that was sized for tile. Engineered hardwood is usually fine within the manufacturer's surface-temperature limit, but the limit is real and it caps output.
Retrofits are where we are most cautious. Adding loops under the floors of an existing two-storey in Ancaster or a walkout in Waterdown means access from below for every bay, and if the room's heat loss is higher than a floor can deliver at a safe surface temperature, radiant on its own will not hold it in February — a supplementary source is part of the design, not an admission of failure. If you already have hot-water heat, our boiler repair and installation page covers the heat source, and heating services covers the forced-air alternatives worth pricing beside it; for the full picture on a project, ask us to look at it.
Radiant floor heat is worth quoting when
- You are pouring a new basement, addition or garage slab and the loops can go in before the concrete
- A basement feels cold underfoot no matter how much forced air you push into it
- You already heat with a boiler and want to add a zone rather than a whole new system
- The room has no good place for ducts, registers or a wall-mounted head
- You want a bathroom or mudroom floor that is warm to stand on in January
How it works
We check what is above and below the loops — slab or joists, insulation, finish flooring — and run the room's heat loss to see whether a floor can actually carry it at a safe surface temperature.
Loop lengths and spacing, manifold location, mixing valve or injection control to protect the loops from full boiler temperature, and a thermostat with a floor sensor so the finish flooring is never overheated. Quoted in writing.
Loops laid and pressure-tested before anything covers them, manifold set and labelled by room, system purged of air, then the curve set and each zone verified once the floor is finished.
Common questions
Can I put radiant floor heating in a house I already own?
In specific rooms, usually yes — a basement, an addition, a bathroom, or any area where the joist bays can be reached from below. Retrofitting a whole finished house is rarely worth it, because getting to the underside of every floor costs more than the comfort gain. We will tell you where the line is for your house before you spend anything.
Does it work with a heat pump instead of a boiler?
It is the natural match for one, because in-floor loops are happy at low water temperatures where an air-to-water heat pump is efficient — far more so than radiators sized for 80°C water. Whether it works for your whole house depends on the heat loss; can a heat pump replace a boiler covers the same question from the radiator side.
How long does it take to warm up?
A slab is measured in hours, not minutes — the concrete stores the heat and gives it back slowly, which is why in-floor systems are run at a steady setpoint rather than set back deeply overnight. Staple-up under a wood floor responds faster but still lags forced air noticeably.
What flooring can go over it?
Tile and stone are ideal because they conduct well and tolerate the temperature. Engineered hardwood is generally acceptable within the flooring manufacturer's limits. Thick carpet with a foam underpad, or a floating floor over heavy underlay, insulates the loops from the room and should be decided before the system is sized, not after.
Do you install it in new construction?
Yes, and that is the easiest time to do it — the loops go down before the pour and the manifold location can be chosen rather than found. See new construction and addition HVAC for how it fits into the rest of the mechanical schedule.