What temperature should you leave your hot tub on?

Posted by Nick Clamp in Maintaining a Hot Tub Guides on 11th May 2022

Looking to keep your hot tub running costs down?

Then you should turn your home spa down when you’re not using it, right?

Well, not exactly…

Read on to find out what temperature you should leave your hot tub on between soaks to save as much money as possible.

What temperature should you leave your hot tub on when not in use?

If you use your hot tub every few days or more, you should leave it at its regular temperature even when you’re not using it

Because spas are so well-insulated, once they get up to temperature it doesn’t take much energy to keep them there. 

That means you’ll actually use more energy turning your hot tub down and then heating it back up when you want to use it than if you just leave it at the temperature you like to soak, in between uses.

Plus, most hot tubs’ temperature rises between 3 to 6 degrees an hour. That means if you turn your hot tub down or off, you’ll have to wait a while for it to get up to a comfortable temperature to soak in

It’s also worth keeping in mind that if you turn your hot tub off completely between uses, its water will sit and stagnate rather than being circulated through the filters. This will turn it into a breeding ground for bacteria and cause problems like green or foamy hot tub water.

© Award Leisure

When turning your hot tub down can save you money

If you use your hot tub a few times a week, the most cost-effective thing you can do is leave it at the same temperature, even when it’s not in use. 

But there are a few cases where you can shave a bit off your electricity bills by turning your spa down.

If you’re going on holiday for between two and six weeks, turn your hot tub down about five degrees. If you’re going this long without using your spa, you can save a bit of money if you turn it down and heat it up again once you’re back home. Just be sure to add a few scoops of hot tub shock before you set off so you don’t come back to an unsanitary spa. And remember to heat it back up plenty of time before you’re planning on taking your first dip.

If you won’t be using your hot tub for six or more weeks, turn it off and drain it. Even running it at low temperatures will cost you more than leaving it off for this length of time. Plus, leaving a hot tub sitting unused for months is a surefire recipe for bacterial growth.

How to keep your hot tub running costs down

If turning your hot tub down won’t save you money, what will?

Here are a few simple ways to cut your hot tub running costs that do work:

Keep it insulated

Your hot tub’s insulation makes a huge difference in how much it costs to run.

To keep your electricity bills as low as possible, go for a home spa that’s been fully insulated with high-quality foam. Stick to WhatSpa? recommended hot tub brands to avoid being stung by a cheap grey import that’s only insulated by a thin thermal wrap (a corner less reputable brands tend to cut).

Cover up

Hot tubs lose around 60% of their heat through the surface of their water. Which means a cover that does a terrible job of trapping your hot tub’s heat in could cost you a bomb.

Look out for hot tubs with covers that are filled with high-density polyurethane foam that’s at least four inches thick at the centre. The best covers also lock in place and have a ‘continuous heat seal’ that traps heat in. 

For an extra layer of money-saving insulation, pick up a thermal spa blanket, which you can float on your hot tub’s surface when you’re not using it to help trap the heat in. 

© Outdoor Heaven

Protect your spa from the elements

If your garden allows for it, tucking your hot tub away from the elements will protect it from the wind and keep its running costs down – as well as making it a lot more pleasant to sit in.

If your garden doesn’t have a natural alcove to slot your spa into, you can slash running costs by installing a windscreen, planting a hedge, or building hot tub housing around it to act as a buffer from the wind. This will also have the added benefit of lending some extra privacy to your soaks.

Close the jets

Leave your spa’s air jets open when you’re not using it and cold air will rush into your hot tub and cool it down. So, be sure to keep them closed when you hop out of your hot tub to reduce the running costs.

Keep your filters clean

Fail to clean your filters as part of your regular hot tub maintenance routine and they’ll take more electricity to run. So, clean them every week and replace them every year to make sure they’re working as efficiently as possible. 

Winterise your hot tub

Know your spa isn’t going to get much use over winter and looking for ways to shave money off your energy bills? Winterise your hot tub – drain it, prepare it to sit stagnant for a few months, and leave it turned off at the mains – and you could significantly cut down your spa’s running costs.

Cool things down in summer

It’s a matter of personal preference, but a lot of people like their hot tub a bit cooler during summer so they can slip in for a refreshing soak on a hot day. Reducing your spa’s temperature by just a few degrees isn’t just more comfortable in the baking heat, but can also make a sizable dent into your hot tub running costs.

© RotoSpa

The final word

If you use your hot tub a few times a week, you’ll (counterintuitively) save the most money by leaving it at the temperature you enjoy soaking at. So, instead of turning it down, stick to money-saving tips we’ve shared in this article to cut your hot tub running costs.

However, it does make sense to turn your spa down when you’re off on holiday for a few weeks, when you should drop the temperature by around five degrees. And if you won’t be using your spa for a few months, you should drain it and turn it off.

For more expert advice on buying, installing, and maintaining a hot tub – as well as a shortlist of the most energy-efficient models on the market – pick up your free copy of WhatSpa? magazine.

About the author

Nick Clamp

I am the Editor-in-Chief at WhatSpa? Media Group and my job is to keep you informed about the very latest hot tubs on the UK market... the best job in the world! When I'm not being deluged with press releases and hot tub brochures I enjoy keeping fit and participating in endurance events including triathlons and distance running.

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