Eight sizes, priced
Each row is a full plan in the designer: tap a size to open it, then change anything.
| Size inside | Where | Heater | Seats | Priced |
|---|---|---|---|---|
| 5 ft x 6 ft | indoor | Harvia 6 kW | 2 | $5,770 |
| 5 ft x 7 ft | indoor | Harvia 6 kW | 2 | $6,268 |
| 6 ft x 7 ft | indoor | Harvia 8 kW | 3 | $6,329 |
| 5 ft x 7 ft | outdoor | Harvia 6 kW | 2 | $8,525 |
| 6 ft x 7 ft | outdoor | Harvia 8 kW | 3 | $8,490 |
| 7 ft x 8 ft | outdoor | Harvia 9 kW | 3 | $10,562 |
| 8 ft x 8 ft | outdoor | Harvia 24 kW wood | 4 | $13,030 |
| 7 ft x 10 ft | outdoor, L bench | Harvia 9 kW | 5 | $11,207 |
Prices are store listings read October 8 to 9, 2026, cedar lining, before freight, tax and the electrician.
What a good sauna plan includes
- A heater sized to the room, with the maker's rated volume range and the glass counted.
- Bench heights measured down from the ceiling, not up from the floor.
- The vents: where the intake, exhaust and drying vent go, and how big.
- The envelope: insulation, foil vapor barrier, the air gap, the boards.
- A cut list and a materials list you can take to the store, with quantities that match your size.
- The electrical numbers your electrician needs: heater amps at 240 V and the 125 percent conductor size.
Fixed plans or made to size
A fixed plan is fine if your space happens to match it. If it does not, every number moves: the stud count, the joist length, the number of boards, the bench lengths, and often the heater. The 6 ft x 7 ft indoor room takes a 8 kW heater for 294 cu ft; stretch it to 7 x 8 ft and you are past what that heater is rated for.
Questions people ask
Are there free sauna plans?
There are free layouts and blog builds of one fixed size, usually without a priced list. The designer here is free: it draws your size and prices every line. Paid PDF plans of a single fixed size sell for roughly 25 to 75 USD.
What size should sauna plans be?
Count 24 in of top bench per person, about 43 in of depth for two bench tiers plus 30 in to stand, and a ceiling of 84 to 90 in. A 6 x 7 ft room seats three; 8 x 8 ft seats four on a straight bench, more with an L.
Do I need a permit for a backyard sauna?
Often for the electrical work, and for the building once it passes your town's size limit for sheds and accessory buildings. Rules vary by town: ask the building department with your footprint.
Sources
Every rule the planner applies comes from the heater maker's own manual or product data where one exists. Where a number is our own default, the designer says so next to it.
- 01HUUMDROP 2.0 electric heater user manual (EU, v6)Room 2000 to 2300 mm high, never under 1900 mm; top bench 1100 to 1300 mm below the ceiling; 50 to 100 mm insulation, foil with taped joints, 10 mm gap behind the boards, 12 to 16 mm boards, 100 mm from the floor; supply air 50 to 100 mm at or below heater mid-height (400 mm), exhaust twice that on the opposite wall at least 200 mm higher (600 mm), drying vent under the ceiling; six air changes an hour; only a certified electrician connects the heater.Read 2026-10-09
- 02HarviaHow do I select the correct heater power?Each square meter of stone, glass or similar uninsulated surface adds as much load as 1.2 cubic meters of room volume.Read 2026-10-09 (search listing; the page answered 403)
- 03HarviaHow to design a saunaThe seat for one person is usually 60 cm wide.Read 2026-10-09
- 04Haven of HeatHeater listings with the maker's room rangesHarvia KIP 4.5 kW 100 to 210 cu ft, 6 kW 170 to 300, 8 kW 250 to 425; Cilindro 9 kW 141 to 494; Harvia M3 212 to 459; Pro 20 283 to 706.Read 2026-10-09