Are hot tub expensive to run?

Posted by Nick Clamp in Maintaining a Hot Tub Guides on 20th May 2021

One of the most common questions new hot tub buyers ask is “How much does it cost to run a hot tub”. The answer is probably not as much as you might think (if you buy a good one!).

In this article, we’ll take a deep dive into hot tub running costs and walk you through exactly how to keep them down.

How much does a hot tub cost to run?

There are three main factors to take into account when it comes to how much it costs to run a hot tub:

  1. Electrical running costs
  2. Servicing and maintenance
  3. Consumables and water care products

Let’s tackle these one by one and so you’re crystal clear on how much you can expect to pay every year.

1. Electrical hot tub running costs

Photo © Villeroy & Boch

Without getting too technical, it’s difficult to quantify exactly how much of an impact a hot tub will have on your electricity bills.

That’s because its energy consumption depends on so many variables, including:

  • the size and model of your hot tub
  • the ambient temperature outside
  • how often you use your hot tub
  • how long you use it for each time
  • how much of that time is with the jets on
  • the water temperature that you prefer,
  • and your electricity tariff

How much electricity does a hot tub use?

We can however make some assumptions based upon an average use pattern of 30 to 45 minutes use, three or four times a week (which is about average for most people who own hot tubs). This is also depends on whether you choose a ‘plug and play’ hot tub or a hot tub that requires a dedicated power supply – see our guide on 13 amp vs 32 amp hot tubs.

The most energy-efficient hot tubs on the market will cost between 75p and £1.00 a day based on these assumptions at current energy tariffs of around 12-14p per kWh.

However, not all hot tubs are built to the most efficient energy standards. If you chance your arm on a cheap grey import this daily cost could increase five or six fold, as they are simply not built to retain heat and maintain water temperature efficiently.

What may seem like a bargain buy at first may have you running for the proverbial hills when your first electricity bill hits the doormat!

So, be sure to keep this in mind when you’re weighing up how much a hot tub costs, as opting for a cheap model can cost you literally hundreds of pounds ever year.

See a preview of recent hot tub reviews for guidance on how to find the best hot tub for your budget and not get stung by a cheap grey import from a disreputable retailer.

  • Hot tub heater
  • Hot tub pumps, air blowers and other electrical components
  • The volume of spa water
  • How well insulated the hot tub cabinet area is
  • The quality and insulation value of the hot tub cover

The factors that affect a hot tub’s energy efficiency:

The heater

Photo © Villeroy & Boch

The vast majority of hot tubs use an electric heater to heat the spa water to your preferred ‘set temperature’, which is normally between 37°C and 39°C.

Once your hot tub reaches this water temperature, it stays at this set temperature all of the time. An insulated hard cover on top of the hot tub preserves the water temperature when you’re not using it so you can use your hot tub whenever you like without having to wait for it to heat up.

Heaters come in different kW ratings, but this won’t directly affect energy usage. That’s because a heater with a larger kW rating will heat the water faster, but it won’t need to stay on as long.

For example, if a 1.5kW heater takes two hours to raise the temperature by 1°C, then a 3kW heater would only take an hour. This ends up being six and two-threes in terms of energy consumption.

However, some heaters use more energy-efficient heating elements to transfer heat more effectively. For instance, a titanium hot tub heater will conduct heat more efficiently than a stainless steel one so keep an eye out for that in the specifications.

The pumps, air blowers and other electrical components

Photo © HotSpring

The pumps, air blowers and other electrical components

The volume of spa water

The more water your hot tub holds, the more it costs to run.

A good rule of thumb is to choose a hot tub that has around 200-250 litres of water capacity per bather seat. Unless you need a huge party spa, there’s no point buying a hot tub that is much bigger than you need for your average number of regular bathers.

How well insulated the hot tub cabinet area is

The insulation materials used inside the cabinet of the hot tub around the underside of the shell and the area around the plumbing system can make a huge difference to its electrical running costs.

Hot tubs with high-density foam insulation are the kindest on your smart meter readings.

So, look out for spas insulated with multiple layers of high density, water-repellent, closed-cell polyurethane foam to keep heat loss and running costs as low as possible.

The only area of the most efficient spas on the market that isn’t insulated is the equipment bay, as the pumps and control box need to be ventilated and easily accessible for service. But apart from the equipment panel, the more insulated a hot tub – and the higher quality the insulation – the better.

This is one of the main areas where cheap grey imports fall down, as they scrimp on the areas that are out of sight, like insulation and the build quality of the spa frame.


The quality and insulation value of the hot tub cover

Photo © Caldera Spas

Good quality hot tubs come equipped with a foam-insulated hot tub cover that folds in the centre with a ‘continuous heat seal’ along the underside of this fold. They are typically tapered to allow rain water to run off the spa.

Look for a hot tub with a cover that’s at least four inches thick in the centre and tapers down to a minimum of two inches at the front and back of the spa.

One thing that’s sure to skyrocket your hot tub running costs is an ill-fitting cover. Your cover should form an airtight seal around the shell of your spa, or else heat will constantly escape, costing you a small fortune over time

A sign of a good cover is when frost or snow gathers on top of the cover in winter without melting, which proves exactly how efficient they are at preventing heat loss.v

“The most energy-efficient hot tubs on the market will cost between 75p and £1.00 per day at current energy tariffs of around 12-13p per kWh”.

2. Servicing and maintenance

Photo © Villeroy & Boch

Just like your boiler at home, we recommend that you have your hot tub serviced by a qualified service engineer at least once a year.

You can choose to pay for a one-off service as and when required, but most WhatSpa? Approved dealerships offer service plans that include an annual mechanical service with the option of upgrading to more regular service visits which include drain down, refills and spa valeting services.

A typical one-off hot tub service will cost between £150 and £200 and service plans start from £25-£30 per month and can increase to around £45-£50 per month with quarterly drain downs provided by the dealer.

This is why it is vital to choose a good quality local supplier in the first place, as your ongoing servicing costs will then be minimised due to shorter travel times.

3. Consumables and water care products

The final element of ongoing expenditure is related to your ongoing water quality maintenance equipment, chemicals, and replacement parts like new hot tub filters.

It costs in the region of £250 – £350 a year to replace filters once per year as recommended and purchase a typical year’s worth of water care products.

What about water usage?

Most people who own spas tend to take fewer baths and more showers.

Because a ten-minute shower uses around half as much water as a bath, hot tub owners actually tend to save money on their water bills.

The cost of running a hot tub

While hot tub running costs can vary massively, if you add up all of the factors for an average-sized (good quality) hot tub that’s used three or four times a week for around 30-45 minutes at a time, you can typically expect to pay:

  • £275 – £365 in electricity
  • £150 – £300 in service costs
  • £250 – £300 for consumables and water care

Making the total cost of running a hot tub £675 – £965 a year.

That’s significantly less than a daily latte from your local Costa or Starbucks – and allows you to enjoy all the health benefits of using a hot tub.

So if you value your physical and mental health, your sense of overall wellness, your sleep quality and the quality of the time that you spend in a tech-free zone actually talking to your loved ones, a hot tub represents very good value indeed!

How much does a hot tub cost to run a week?

A hot tub typically costs between £13 and £18.50 a week to run – around the same as a round of drinks at the local pub.

How much to run a hot tub per day?

A hot tub costs around £1.85 and £2.65 a day to run – about as much as a latte from the nearest coffee shop.

How to run a hot tub economically

There’s plenty you can do to make dramatic savings on your hot tub running costs, such as:

Buy a quality home spa

Buying a cheap spa will cost you far more money in the long run than opting for a premium model.

You can half your hot tub running costs by buying a model from a reputable brand that’s fully insulated with multiple layers of high-quality foam, features an energy-efficient heater, and has a perfectly fitted and foam-insulated cover.

Shield it from the wind

If your hot tub is located in a wind trap it will have to work a lot harder to maintain the right temperature.

So, be sure to install it in an area that’s shielded from the wind to help keep running costs down.

Switch energy providers

Save money on your hot tub without changing the way you use it at all by making sure to shop around for the cheapest energy provider.

Make sure you’re always paying as little as possible for your electricity by using a comparison site every year to switch to the lowest energy tariff available to you.

Make sure the cover is sealed every time you get out

Hot tubs lose around 60% of their heat through the surface. If your cover isn’t properly sealed when you’re not using your spa, energy consumption will go through the roof while it works harder to maintain the same temperature.

Avoid this by making sure your cover is properly sealed every time you get out of your hot tub.

Close the air jets

A simple way to save money is to close your spa’s air jets when you’re not using it, as these introduce cold air to your hot tub and cause heat loss.

Turn the temperature down

Cooling your hot tub down a few degrees can lead to huge savings in the long run.

Even if you like your spa on the hot side, you can make a serious dent in your electricity bill by cooling it down to around 30 degrees when you go on holiday or you know you’re not going to be using it for a while.

Clean your filter

A clean filter is an efficient filter. Be sure to clean your filters every week and replace them every year to make sure they’re working as efficiently as possible.

Maintain pH levels

Keep your hot tub’s pH level between 7.2 to 7.8 at all times to ensure chlorine and other chemicals you treat the water with work as effectively as possible.

Be particularly careful to keep its pH above 7.2, or the water will become acidic and could eventually corrode the heater, landing you with a costly repair bill.

Is it cheaper to leave a hot tub on all the time?

It might seem counterintuitive, but it’s more cost-effective to leave your hot running all the time.

That’s because your hot tub’s heater has to work a lot harder to heat the water from scratch than it does to maintain a steady temperature given how well-insulated they are.

In Summary:

If you add up all of the elements of hot tub running costs for an average sized (good quality) hot tub, used 3 or 4 times per week for around 30-45 minutes per session, including servicing and hot tub maintenance, the annual cost will be in the region of £750 – £950 which is significantly less than a daily cup of latte or cappuccino from your local Costa or Starbucks!

So if you value your physical and mental health, your sense of overall wellness, your sleep quality and the quality of the time that you spend in a tech-free zone actually talking to your loved ones; a hot tub represents very good value indeed!



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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