The 2026 hot tub energy report

A median 197 W, the power a covered, idle tub draws to hold its temperature. Bigger tubs hold more water and lose more heat, so the median climbs with every size class.

Sundance Spas, at a median 69% of California's limit, among brands with 5 or more matched filings. Raw watts would favor brands that sell small tubs, so the chart uses each tub's share of the limit for its own volume.

In this data, yes. Full-foam tubs drew a median 84% of the limit and perimeter-insulated tubs 92%. Full foam fills the space between the shell and the cabinet and wraps the pipes; a perimeter design lines the cabinet walls and floor and leaves an air space around the plumbing. Brands overlap, so judge a tub by its own figure.

No. Value tubs drew a median 84% of the limit and luxury tubs 92%. What the higher tiers add, mostly pump power, jets and longer warranties, is set out in luxury vs budget hot tubs.

85 of 301, or 28%, draw at least 95% of the standby power the state allows for their volume. Every listed tub passes; these pass with the least room.

The three lowest standby figures in each size class are below. Lower watts in the same class means the shell, foam and cover hold heat better, or the equipment idles on less. Every matched tub is ranked on which hot tubs use the least power.

California lets no portable electric spa be sold in the state until it is tested and listed in the Energy Commission's appliance database. The lab fills the tub, holds the water at temperature with the maker's cover on and nobody in it, and records the power it draws. The listing shows that figure and the legal limit for the tub's volume.

We matched 317 hot tubs in our catalog to their listing by maker and model number, using the lowest figure where a model has several listings. The listings are dated 2019 to 2026. Every figure here is a median of those filings, and it updates when the data does. Swim spas are tested under a separate category and are left out.

Standby is a floor, not a bill. It leaves out soaking with the jets on, an open cover, cold nights and heating fresh water after a refill. It is still the one power figure measured the same way for every tub, which is why we compare on it.

From a September 2008 factsheet by Washington State University's Extension Energy Program, not from a test of today's tubs. It says portable spas use an average of 2,514 kWh a year, in the sentence after a National Spa and Pool Institute count of about 3.4 million US spas in 2000, and it doesn't say how that average was worked out. The only test results it prints are for 8 tubs, from a 2004 Canadian study, and it promised an update once California's testing reported.

California now lists every portable spa sold there with its measured standby power, and this report is built from those listings. The 317 we matched put the median tub at 197 W, about 1,726 kWh a year if it held that draw all year. The two figures measure different things: 2,514 kWh is a yearly total for all use, while standby leaves out soaking and refills. Treat the 2008 number as history and the filings as the current measurement.

Yes, under CC BY 4.0 with the credit “Data: HotTubFinder.com” and a link. To cite the report:

Journalists: the press page lists our findings and how to reach us.