Sauna heater size calculator
Enter your cabin dimensions and this works out the heater rating, the electrical supply it needs and whether three phase is likely. It sizes on volume with corrections for glass and masonry, which is how it should be done and usually is not.
Indicative. We confirm against your distribution board at survey before quoting.
How the calculation works
The rule
Roughly one kilowatt of heater per cubic metre of cabin volume, then adjustments. Volume means width by depth by ceiling height — floor area alone will give you the wrong answer, and it is the most common sizing mistake in this market.
Why glass counts against you
A square metre of glass loses heat several times faster than a square metre of insulated timber wall. The calculator adds roughly one kilowatt for each square metre of glazing, which is why a cabin with a full glass front typically needs a heater one size up from the same cabin with a solid wall.
Why masonry counts too
Stone, tile and blockwork inside the cabin absorb a great deal of heat before the air reaches temperature. It is the same thermal mass problem that governs steam generator sizing, and it is why a sauna built against a bare tiled wall never quite performs.
Ceiling height is the lever worth pulling
If your room is 2.6 or 3.0 metres, dropping a false ceiling inside the cabin to 2.1 metres removes a large slice of volume you were never going to sit in. It usually saves a heater size, and that saving repeats on every electricity bill for the life of the cabin.
Where the electrical line falls
Up to 6kW is a dedicated 32A single phase circuit, which most villas and many apartments can take if the board has a spare way. From 9kW you generally need three phase. That threshold is why apartments so often end up with an infrared cabin instead.
Questions we get asked most
How many kW does my sauna heater need?
Roughly one kilowatt per cubic metre of cabin volume, plus about one kilowatt per square metre of glass, plus a margin for any masonry or stone surface inside the cabin and for outdoor locations. A 1.8 by 2.0 by 2.1 metre cabin needs around 8kW.
Does ceiling height really matter that much?
Yes. A 1.5 by 2.0 metre cabin at 2.2 metres is 6.6 cubic metres. The same footprint at 3.0 metres is 9.0 — a 36 percent larger load for a room that looks identical on plan.
When do I need three phase?
Generally from 9kW upward. Villas in Dubai commonly have a three phase supply available; apartments usually do not, which often decides cabin size or pushes the project toward infrared.
Is a bigger heater safer?
No. An oversized heater overshoots, cycles hard and cooks the timber immediately around it. Correct sizing matters in both directions.
Want it checked properly?
Send the dimensions on WhatsApp and we will confirm the heater and check what your board can actually take.
- COMPANY
- PK Technical Services Co.
Established 2024 - ADDRESS
- Madina Mall, Muhaisnah 4
Beirut Street, P.O. Box 211516
Dubai, United Arab Emirates - CALL OR WHATSAPP
- +971 50 123 4567