What size sauna heater do I need?
Find the right sauna heater size in kW: measure the room, add volume for glass and stone using each maker's rule, then check the amps at 240 V.
Guides
Sauna guides, in plain language
Size a heater, brief your electrician, choose stones and plan a backyard sauna. Every guide uses the manufacturers’ own documents and lists its sources.
Heaters
Size your heater, and choose between electric and wood.
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Wood-burning vs electric sauna heaters for outdoor saunas in Ontario
Wood-burning or electric heater for an outdoor sauna in Ontario? Compare heat-up, running cost, installation, upkeep, WETT inspections and burn rules.
Controls & electrical
Controls, contactor boxes and what your electrician needs to know.
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Sauna controls and contactor boxes, explained
Built-in or external control, and do you need a contactor box? How Harvia, HUUM and Homecraft controls pair with heaters, and where they go outdoors.
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Sauna heater electrical checklist for Ontario: what to hand your electrician
Wiring a sauna heater in Ontario? Who can do the work, the ESA notification, breaker and wire from the manual, panel capacity and where the contactor goes.
Stones & accessories
How much stone to order, which types to use and how to stack them.
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How many sauna stones do I need? Types, amounts and stacking
How many kilograms of sauna stones your heater needs, which stone types and sizes are safe, how many boxes to order, and how to stack them the right way.
Outdoor saunas
Styles, prices and getting your yard ready for delivery.
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Outdoor sauna prices in the GTA (2026): what each style and size costs
What outdoor saunas cost in Toronto and the GTA in 2026: starting prices by style and size from Ontario sellers, what's included and what adds cost.
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Barrel vs Luna vs cube vs cabin vs A-frame: choosing an outdoor sauna style
Compare barrel, Luna, cube, cabin and A-frame outdoor saunas side by side: seating, footprint, look, heat-up, snow and starting prices.
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Outdoor sauna site prep: base, delivery access and permits
Planning a backyard sauna? Check permits and zoning, choose the spot, build a level base, and plan delivery access and power, with Ontario and Toronto rules as worked examples.
Not sure where to start?
The Heater Finder asks for your room size and glass area, then shows only heaters their makers rate for it. Or send us your measurements and we’ll check.