Home sauna electrical fit & cost planner

Start with the panel, not the cabin

Enter the space, service rating and major home loads. The result pairs a manufacturer-listed heater range with an existing-service estimate, then adds your real purchase price, installation quote and electricity rate. About ninety seconds; no signup.

Nothing you enter leaves your browser. This is a planning estimate, not a permit or load calculation of record.

Step 2 / Your existing service

What is the rest of the house already using?

This is the part the calculators checked for this site do not ask about. A 6 kW heater is a 25 amp continuous load, and a panel that is already close to its limit does not care how well-chosen your cabin was.

Main service rating

Heated floor area of the home (sq ft)

Code basis for the capacity check

Check everything the home already has. Figures are typical nameplate placeholders — open the appliance door and replace them with your own where you can.

Why the third box matters. The existing-dwelling calculation was renumbered and rewritten in the 2026 NEC, so there is no single current method to default to. On 2020 or 2023 NEC (220.83) this planner takes general lighting and receptacles at 3 VA/sq ft, totals the connected load including the heater, applies the first 8,000 VA at 100 % and the remainder at 40 %, and counts air conditioning or electric space heating at 100 % under 220.83(B). On 2026 NEC (120.83) it takes 2 VA/sq ft, applies 100 %/40 % to the existing load, and adds the new sauna heater at 50 % as an “other new load”. If you pick I don't know, you get the figures but no pass or fail, because a calculation run under the wrong edition is a different answer rather than a safer one. Either way this is an estimate for a planning conversation, not a load calculation of record — that is signed by your electrician, using your actual nameplates and your local amendments. The electrical requirements page sets out both methods, with their source class.

Step 3 / Real project cost

Use your quote, not a national average

These fields are optional. Enter the numbers you actually have and the planner will keep unknown items visibly out of the total instead of inventing them.

Sauna or heater price (USD)

Electrical + site-work quote (USD)

Electricity rate ($/kWh)

Sessions per week

Minutes per session

Electricity is shown at the heater's full rated draw, so it is a planning ceiling. Actual use is usually lower after warm-up when the thermostat cycles. The installation field should come from a local written quote based on the exact model, route, permit and panel work.

Step 4 / Optional

Adding a cold plunge?

No Yes, outdoors or on a slab Yes, on a floor above a basement or crawlspace

Your result

What to hand your electrician

Keep this plan for later

A sauna is rarely bought the same day it is planned. This saves what you entered and the one-line result to this browser on this device, so the next visit can offer to continue instead of asking for the measurements again. Nothing is uploaded, nothing is shared, and no other site can read it. One plan is kept — saving again replaces it.

Also worth knowing: the figures behind this result carry their own read dates. If a manufacturer document is re-read after you save, the saved plan says so when you come back, rather than quietly ageing.

Sources for every threshold above

Heater sizing and clearances — Harvia KIP installation manual · HUUM DROP U.S. user manual · HUUM DROP product specifications · Harvia sizing sheet · HUUM sizing sheet. The model tables this planner sizes from, with each figure's source URL, read date, voltage and verification status, are published at models.json. Circuit sizing — Sun Home electrical requirements · Haven of Heat wiring guide. Existing-dwelling load calculation — NEC 220.83 (2020/2023) · EC&M on the 2026 NEC dwelling-unit changes · 2026 NEC 120.83 course summary (secondary source). Bench and ceiling clearances — Sauna Place dimensions guide. Ventilation — Thermal Finn. Floor loading — IRC 2024 R301.5.