Start with how you'll actually use it, not the specs. Are you building a quiet, solo retreat for yourself, or a space where you'll regularly host a partner, family, or friends? A 1–2 person sauna keeps things intimate and heats up faster, while a larger model with multiple bench tiers makes sense if you're picturing regular group sessions.

It's worth being realistic here rather than sizing up "just in case." A sauna built for two people who use it most evenings gets more genuine use than a large, six-person sauna that mostly sits empty. Think about your household, how often you'll realistically use it, and whether you're after a personal ritual or a shared one — the right size follows from that.

Once you know how many people it needs to comfortably fit, the heater and insulation get matched to that space. A heater that's mismatched to the room — too small to keep up, or too large for an under-insulated space — is a common source of both comfort issues and failed electrical inspections, so this is worth working through with us rather than guessing.

For a prefabricated barrel, cabin, or pod-style sauna, installation typically breaks into two parts: assembling the structure itself, and connecting power (or a chimney, for wood-burning models).

Structural assembly is generally DIY-friendly — most kits are designed for two people with basic tools and a weekend, sitting on a prepared gravel pad, patio stones, or an existing deck rated for the load. The electrical connection is not a DIY step. That part requires a licensed electrician, from running the circuit to the final inspection.

This is the question almost everyone asks, and the honest answer is: it depends on your municipality, but here's the general shape of it in Ontario.

Under Ontario's Building Code Act, a detached accessory structure under 107 square feet (10 square metres) generally doesn't require a building permit, provided it isn't attached to your house and doesn't include plumbing. Some municipalities have extended this threshold further — Toronto and a few others now exempt structures up to 161 square feet — but the base provincial rule is 107 square feet, and requirements do vary by city, town, and county. Before you buy, it's worth a quick call to your local building department to confirm the threshold and any zoning setbacks (distance from property lines, height limits) that apply where you live.

Here's the part that catches people off guard: even if your sauna's structure is exempt from a building permit, an electrical permit is essentially always required if you're installing a hardwired heater. That's a separate process from the building permit, and it's not optional.

For a hardwired electric heater, plan on a dedicated 240V circuit, sized by your electrician based on the heater's rated amperage and your sauna's distance from the panel. For an outdoor installation, this usually means weather-rated wiring, GFCI protection, and often a run of underground conduit from the house to the sauna — which is worth factoring into your budget and timeline alongside the sauna itself.

If you're going with a wood-burning heater instead, there's no electrical supply to plan for at all — just the chimney and appropriate clearance from combustible materials.

Yes, in almost every case. Any new dedicated circuit — which is what a hardwired electric sauna heater requires — needs to be installed by a licensed electrician and inspected under the Electrical Safety Authority's requirements in Ontario. This holds true whether or not your structure itself needed a building permit. The two permits are independent of each other, and skipping the electrical one is the riskier of the two to skip.

The one exception: a wood-burning sauna heater doesn't touch your electrical panel at all, so there's no electrical permit involved. It still needs a chimney installed to code, and your municipality may have separate requirements for wood-burning appliances, so it's still worth a call to confirm.

A sauna doesn't automatically change your home insurance, but it does need to be disclosed to your insurer like any other permanent structure or fixed appliance, and it needs to be installed to code to stay covered.

The real risk isn't the sauna itself — it's unpermitted or improperly inspected electrical work. If an electrical fire or other damage is later traced back to a circuit that was never inspected, insurers can and do deny claims on that basis. Getting the electrical permit and inspection done isn't just a legal formality; it's what keeps your coverage intact if something ever goes wrong. Once installed and inspected properly, most homeowners simply mention the addition to their insurer and carry on with normal coverage.

Löyly is the Finnish word for the burst of steam and heat you feel when water is poured over hot sauna stones — it's less a technical term and more the whole sensory experience: the hiss, the wave of humidity, the way the room briefly feels more intense. More stone mass in a heater generally means softer, longer-lasting löyly, since the rocks hold and release heat more gradually with each ladle of water.