Sauna build quotes are hard to compare because nobody tells you what is in them. One company quotes a pre-cut kit without a heater, the next quotes a finished room with a crew, and a DIY forum tells you it cost $2,000 without mentioning the electrician. The calculator below prices all three the same way, against the same room, so the numbers line up.
Put in the inside dimensions you have space for. You get the heater size that room needs, the quantities to order, and what each route costs.
Interactive tool
Put in the inside dimensions. You get the heater size your room needs, a materials list with quantities, and three price bands that are costed the same way — so building it yourself is not mysteriously more expensive than buying a kit.
Planning estimates in US dollars, not a quote. Material prices vary by region and supplier, and electrical work is priced by your electrician after seeing your panel. Heater sizing follows the common 1 kW per 45 cubic feet rule with the usual addition for glass; manufacturers often specify one size up.
Quick demo: how the calculator works (43 seconds).
The order of work
Most build problems are sequencing problems. Cladding goes on before the electrician has pulled the cable, or the vapour barrier gets cut to fit a vent that was decided too late. This is the order that works:
Want the wood order in detail? Our sauna wood guide shows the board-by-board takeoff for a 2 × 2 m room.
- Check the rules first. Indoors this is usually nothing. Outdoors a freestanding structure often needs a permit or has to sit a set distance from the boundary, and your insurer wants to know about a wood stove.
- Frame the room and rough in the vents. Stud walls, ceiling, and the openings for the inlet low near the heater and the outlet on the opposite side.
- Electrician, first visit. The dedicated 240V circuit and the cable to the heater position go in now, while the walls are open. This is also when you find out whether your panel has room.
- Insulation, then foil vapour barrier. Foil faces into the room, seams taped, no gaps. This is the layer that decides whether the room heats in twenty minutes or forty.
- Battens, then cladding. The air gap behind the boards matters. Leave the heater wall until the heater position is final.
- Benches, door, trim. Clear grade wood where skin touches, no metal fixings on a sitting surface.
- Electrician, second visit. Heater and controls connected and tested, GFCI verified.
- First burn. Run it hot with the door open for an hour to cure the heater and drive off the smell of new wood.
Which trades you actually need
An electrician: always, for anything electric. A sauna heater over about 4.5 kW needs its own 240V circuit, correctly sized breaker and GFCI protection, and in most places that work has to be done and signed off by a licensed electrician. It is also the line item people leave out of their budget and then discover costs four figures in an older house.
A plumber: only if you add water. The sauna room itself needs no plumbing at all — no drain, no supply. You only need a plumber if you are putting a shower or a cold plunge next to it, or converting a bathroom where a drain has to move. Many builds skip this entirely.
A carpenter or builder: for outdoor cabins and awkward retrofits. A level base, a roof that sheds water and a weather-tight shell are worth paying for. Indoors, a pre-cut kit is within reach of a competent DIYer.
A chimney sweep or stove fitter: for wood-fired. Clearances to combustibles and a correctly rated flue are safety items, not preferences, and your insurance may require proof.
Where budgets go wrong
Three things blow the number. The electrical work, when the panel turns out to be full. The wood, when cedar is chosen for every surface instead of just the benches and backrests — spruce walls with cedar where you sit costs a third less and feels the same. And the heater, when it is undersized to save a few hundred dollars and then never quite gets the room hot, which is the one mistake you cannot fix later without rewiring.
Once the build is costed, work out what it costs to run: our running cost calculator takes the heater kilowatts and your electricity rate. And if you are not yet sure a full build is the right route, the sauna picker compares it against kits, infrared cabins and blankets in five questions.