Inflatable Hot Tub Electricity Costs

How much electricity does a hot tub use?

In the winter, our hot tub uses about 9kwh/day. With a cover or insulation, it uses about 7kwh/day.
In the summer, it uses about 5kwh/day. I haven’t tracked it with insulation in the summer yet.

Our electricity costs about $0.45 per kwh. So without a cover in the winter, it costs about $120/month and with a cover it costs about $95/month. I asked my neighbors in the area on a FB group and 3 told me it added about $100/month to their electric bill. My neighbor with a “real” hot tub uses about 7kwh/month in the winter, which is similar!

I’ve tried to track costs methodically but it’s hard to do! Confounding factors include usage (sitting in it uses more power than leaving it covered), daily outdoor temperature changes, modifying the hot tub temperature on occasion (our daughter plays in it at 100 degrees, not 104), turning it off or refilling it on occasion, not knowing when another person has changed the temperature, occasional poor note taking, etc. But my numbers above feel about right.

Details: We have a 180 gallon, 180 cm diameter inflatable hot tub. We live in the San Francisco Bay, El Cerrito, CA. See The National Weather Service for a temperature almanac

What this means:
Should I get an insulating cover for my hot tub? Meh. Our $100 Cleverspa cover saved us about $150 until it fell apart. And it was a slight bother to put on every time. Maybe a more durable, better insulating cover would be worthwhile.

Should I insulate my hot tub with foam board insulation? Probably! 2 hours work and $50 of insulation is saving me 2kwh/day all winter, that’s ~$200/year.  And it looks like it’s going to last several years! I used R-Tech 1/2 in. x 48 in. x 8 ft. R-1.93 EPS Rigid Foam Board Insulation from Home Depot


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