How many Solar Panels do I Need to Power a Jacuzzi?

By Matthew Wheeland - June 24, 2010

hottub

The energy vampires in your backyard

Hot tubs (especially time machine models) use a gigantic amount of energy, consuming around 2,514 kilowatt-hours of electricity every year (the same amount of energy it would take to power five typical refrigerators in the same amount of time). If you own a jacuzzi, it’s almost certainly sucking up more power than any other appliance in your home. We’ve done the research to see what it would take to power your hot tub with solar panels, in response to a somewhat random reader question (send us more questions! This is fun). We’ve also rounded up some tips for choosing a more energy-efficient hot tub in the first place.

Rough calculations…

So, how many solar panels would it take to power a jacuzzi? The short answer: a lot. No matter how you look at it, hot tubs are using a significant amount of energy. Your location matters in terms of figuring out exactly how much electricity it takes to power the hot tub; colder surroundings, like Minnesota or Maine, make it harder for the hot tub to stay heated and require more energy. As with anything solar, your location also determines how much energy you can expect to produce through solar panels. Let’s say you live in St. Louis, Missouri, where the average temperature is around 55 degrees, and it’s fairly sunny. You’d probably need a 1.65 kWh solar system just to power your hot tub, using 165 square feet of your roof. Another option is to use a solar water heater instead of (or in addition to) solar panels, since most of the energy the hot tub uses is for heating the water. Which brings us to…

How jacuzzis use energy

Electricity heats and circulates the water inside a spa, and a small amount of energy is also used for lighting. Even though hot tubs aren’t in use most of the time, they’re still using power to keep the water heated and pumped. As soon as the tub is in use– and the cover comes off– heat losses skyrocket and even more energy is used. Getting in the hot tub means more lost heat. Using jets takes much more energy than running the pumps that just circulate the water.

Energy-efficient features

Since the heater uses a big chunk of the energy in a hot tub, one of the best ways to save energy is to minimize heat loss. A tight, well-insulated cover that won’t absorb water is one critical part of a more energy-efficient hot tub. Thick walls with water-resistant insulation also stop heat loss. More efficient pumping systems can help save around 15% of the energy used in an average spa. Some pumps have two speeds (one for circulating water, and one for jets) and these aren’t very efficient, especially when the pump is on the lower speed. Having separate pumps for jets and circulation is a better choice.

Feeling too guilty to relax in your hot tub?

If you’ve just realized that your hot tub is making you responsible for more carbon emissions than you thought, don’t despair. By choosing an energy-efficient model, using a solar water heater, and running the pumps off your home solar system, you can reduce your impact. Don’t have a home solar system? Sign up for PURE to get started.

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