Free Expert Tool
Sauna Heater Size Calculator
Enter your room dimensions and we will calculate the exact kW you need — then show you matching heaters from Huum, Harvia, Narvi & more.
✓ Free & Instant
✓ No signup needed
✓ Expert-verified formula
1
Dimensions
2
Glass & Stone
3
Setting
4
Results
Step 1 of 3
Define Your Sauna Space
Enter your sauna room dimensions in feet. Already know the total volume? Enter that instead.
Enter dimensions (L × W × H)
— or enter total cubic volume —
A typical 2-person home sauna is 200–350 cu ft. Multiply L × W × H to get yours.
Step 2 of 3
Cold Surfaces Matter
Glass panels and uninsulated stone/concrete walls drain heat rapidly. Each sq ft of glass is equivalent to 7 extra cu ft of volume. Do not include the floor.
Glass / cold surface dimensions
— or enter total cold surface area —
No glass or stone walls? Leave blank and continue — we will use your room dimensions only.
Step 3 of 3
Indoor or Outdoor?
Outdoor and uninsulated saunas require 50% more heater power to compensate for heat loss to the environment.
Your Personalised Recommendation
Here Is Your Ideal Heater Size
—
kW
Minimum recommended power
Adjusted volume
— cu ft
Setting
—
Rule of thumb
1 kW per 45 cu ft
⚠️ Always size up to the next available kW — never down. A slightly oversized heater runs cooler and lasts longer.
Matching Heaters From Our Catalog
Not 100% sure? Talk to a real specialist — free.
We size heaters all day. One call and you will know exactly what to order.
