120V or 240V: what does it really change?

Voltage doesn’t change the price of a kilowatt-hour. Watts × hours sets your bill. What 240V changes is how many watts a sauna can use (so how fast it heats) and whether you need an electrician first. Compare two saunas below.

Rates: EIA, July 2026 · Install ranges: cost guides, 2026 (grade C)

Your habits

Hours on per session · preheat + session

Sessions per week

Your stateUS average (18.31¢)Alabama (16.4¢)Alaska (28.8¢)Arizona (15.4¢)Arkansas (14.3¢)California (33.6¢)Colorado (17.0¢)Connecticut (24.2¢)Delaware (18.5¢)District of Columbia (25.2¢)Florida (15.0¢)Georgia (16.3¢)Hawaii (48.0¢)Idaho (13.7¢)Illinois (19.2¢)Indiana (16.7¢)Iowa (16.0¢)Kansas (15.3¢)Kentucky (13.8¢)Louisiana (12.7¢)Maine (32.4¢)Maryland (21.4¢)Massachusetts (30.5¢)Michigan (23.1¢)Minnesota (17.4¢)Mississippi (14.5¢)Missouri (16.1¢)Montana (15.0¢)Nebraska (13.8¢)Nevada (12.8¢)New Hampshire (26.6¢)New Jersey (25.2¢)New Mexico (16.1¢)New York (29.9¢)North Carolina (15.2¢)North Dakota (13.4¢)Ohio (19.4¢)Oklahoma (14.3¢)Oregon (16.0¢)Pennsylvania (21.7¢)Rhode Island (28.3¢)South Carolina (15.5¢)South Dakota (15.4¢)Tennessee (13.7¢)Texas (15.9¢)Utah (13.1¢)Vermont (23.8¢)Virginia (17.6¢)Washington (14.7¢)West Virginia (15.8¢)Wisconsin (19.1¢)Wyoming (14.4¢)Enter my own rate…

Verdict

How we calculate this, and our sources

1. Amps = watts ÷ volts.
2. *Code-minimum breaker treats the sauna as a continuous load: the breaker must be at least 125% of the load (so the load uses no more than 80% of the breaker). See NEC 210.19(A)(1) and 210.20(A) (S7). Saunas often run for less than 3 hours, and many makers specify their own circuit. The maker’s spec and your licensed electrician decide. We show both.
3. Electricity = watts ÷ 1,000 × hours per session × sessions per week × 52 × years × rate (flat price).
4. Install ranges are typical published ranges (S8, grade C). Real quotes vary a lot: buyers report $1,500 and $3,000 hookups (S9). Get 2–3 local quotes.

• Sun Home electrical requirements · Clearlight Sanctuary 1 · Sunlighten mPulse Empower
• NEC 125% continuous-load rule (summary)
• 240V outlet install cost guide
• EIA July 2026 · state rates

Recovery Math is reader-supported: if you buy through links on this site we may earn a commission, at no extra cost to you (affiliate disclosure). We analyse published specs and public data; we don’t hands-on test products. Not electrical, medical or financial advice: confirm wiring with a licensed electrician and talk to your doctor before starting heat or cold exposure.