How much does it cost to run a hot tub?

Nick Clamp Posted by Nick Clamp in Maintaining a Hot Tub Guides on 4th October 2019

One of the most common questions that new hot tub buyers ask is “How much does it cost to run a hot tub”, and the answer is probably not as much as you might think (if you buy a good one!). Here the WhatSpa? team investigate the factors that affect hot tub running costs.

When we talk about hot tub running costs there are three main factors to take into account once your fabulous new hot tub has been installed taking pride of place in your garden:

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

Let’s tackle these one by one and help you decide the total question of how much is a hot tub?

Hot tub running costs – the key considerations

1. Electrical running costs

Photo © Villeroy & Boch

Without getting too technical, this is a pretty difficult cost to quantify, as it will depend on the ambient average outside temperature, how often you use your hot tub, for how long each time, how much of that time is with the jets on, the water temperature that you prefer and finally your electricity tariff.

We can however make some assumptions based upon an average usage pattern of 30 to 45 minutes use, 3 or 4 times per week (which is about average for most hot tub owners). The most energy-efficient hot tubs on the market will cost between 75p and £1.00 per day based on these assumptions at current energy tariffs of around 12-13p per kWh.

However not all spas are built to the most efficient energy standards. If you chance your arm on a cheap grey import this could increase five or six fold as they are simply not built to retain heat and maintain water temperature efficiently. So 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! See a preview of recent hot tub reviews for guidance on how to find the best hot tub for your budget.

Here are the factors that affect how energy-efficient a hot tub is:

  • 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

Hot tub 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, with an insulated hard cover on top of the hot tub to preserve the water temperature so that you can use your hot tub whenever you like without waiting for it to heat up.

Heaters come in different kW ratings but this won’t directly affect energy usage. A heater with a larger kW rating will heat the water faster but it won’t need to stay on as long in order to heat up the water. For example if a 1.5kW heater takes 2 hours to raise the temperature by 1°C, then a 3kW heater would only take an hour.

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.

Hot tub pumps, air blowers and other electrical components

Photo © HotSpring

It stands to reason that hot tubs with more electrical gizmos will use more power (when everything is switched on) all things being equal than those with fewer of them. Not all pumps are equal in terms of energy usage so consult with suppliers about this. Modern LED lighting uses very little energy so lighting is less of an issue on this front.

The volume of spa water

It stands to reason that it will use more energy to keep a bigger body of water heated than a smaller one. 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.

What about water usage?

If you are on a water meter we haven’t factored in the cost of water, as most hot tub owners actually use less water when they install a hot tub as they tend to take fewer baths and more showers.

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 electrical running costs.

The only area that will not be insulated is the equipment bay where the pumps and control box is sited (for ventilation and service access) but backwards of this, the general rule of thumb is that the more 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 etc.

The quality and insulation value of the hot tub cover

Photo © Caldera Spas

Good quality hot tubs come equipped with a hard 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 away from the centre downwards.

Look for a thickness of at least 4 inches in the centre and tapering down to a minimum of 2 inches at the front and back of the spa. Also ensure that they are fitted properly so that when they are clipped into situ when the hot tub is not being used, the seal around the spa shell is a good one to prevent heat from escaping unnecessarily.

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.

“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 per year.

You can choose to pay for a one-off service as and when required but most WhatSpa? Approved dealerships offer service plans which 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 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 care products and accessories such as replacement hot tub filters. See our hot tub maintenance and care guide that comprehensively covers this subject. This is an essential area to consider when asking the question ‘how much do hot tubs cost?’

To replace filters once per year and purchase a typical year’s worth of water care products will cost in the region of £250 – £350 per year.

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 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!

Nick Clamp

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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