How Much Does It Cost To Run A Hot Tub – [Complete Expert Guide]

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Before you buy a hot tub, you want to be confident that you’ll be able to enjoy it without worrying about the costs.  The good news is that hot tubs can be run very economically, as long as you manage them properly.  With that in mind, here is a complete expert guide to working out how much it costs to run a hot tub.

How Much Does It Cost To Run A Hot Tub

Hot tub running costs

The main costs of running a hot tub are water and electricity.  You will also need to factor in the cost of cleaning chemicals and replacement filters.  How much, exactly, you will pay will depend on various factors including your region, the size of your hot tub, how you use it and how well you maintain it.

Portable hot tub running costs

In principle, portable hot tub running costs should be exactly the same as for a fixed hot tub of equivalent size.  In practice, this only applies if you buy a quality portable hot tub, i.e. one with effective insulation. 

You also need to take particular care to avoid damage to a portable hot tub as most of them are inflatable and hence can be vulnerable to punctures.  Any damage to a portable hot tub can impact its efficiency and hence increase its running costs.

How much does it cost to run a hot tub per week/day

For the basis of these calculations, we’ll assume you’re running a 5-6 person hot tub, which would typically be about 1250L or 1.25 cubic metres.  We’ll use the Thames Water metered rates for 2020/2021.  These are £1.3818 per cubic metre for water and £0.8963 per cubic metre for sewage (unless you have a septic tank). 

For completeness, if you are on an unmetered rate, the cost of your water will be based on the rateable value of your home rather than how much water you use.  This means, effectively, that you can run a hot tub without additional charges for water.  It is, however, increasingly rare for homes to be on unmetered rates.

We’ll also assume you’re paying the average price for electricity.  According to UK power that’s £0.1437 per kWh.

Water costs

Hot tubs are for relaxation and wellness not for cleanliness.  This means that, if you’re running them properly, you shouldn’t have to clean them after every use the way you would if you were having a regular bath.  Generally, you’ll be fine changing the water once a quarter.

This means that if you’re running a 1250L hot tub then your total water cost will be just £2.85 per quarter.  That works out at about £0.24 per week or £0.034 per day.

Electricity costs

This is where life gets a little complicated.  The most obvious cost (and the easiest one to calculate) is the cost of heating the water in the first place.  Assuming you choose a hot tub with effective insulation and remember to keep the cover on out of use, then the cost of keeping it heated in between uses should be fairly minimal.

Heating a hot tub

Let’s assume water is about 13℃ when it comes out of the tap.  You want to heat it to 38℃ and you have a 3Kw heater.  As a rule of thumb, you can expect the water temperature to increase by about 2.5℃ per hour so it will take about 10 hours to heat the water.  Running a 3Kw heater for 10 hours uses about 30Kwh of electricity so the cost would be 0.1437*30 or £4.31.  That’s about £0.36 per week or £0.05 per day.

Running a hot tub

Let’s assume that you use your hot tub about three times a week for about half an hour a time.  Combining the pump (during use) with filtering and heating, you’re probably looking in the region of 45KwH per week so the cost would be 0.1437*45 or £6.47 which is £0.92 per day.

Filtering and cleaning a hot tub

Assuming your hot tub has two filters and you change them once a year (as recommended), you’re looking at about £60 per year for filters.  That works out at £1.15 per week or £0.16 per day.  Budget about £150 a year for cleaners so that would be £2.88 per week or £0.41 per day.

In total

Putting everything together, you’d be looking at about £11.1 per week or £1.56 per day.  Please be aware that this is a baseline.  The main purpose of this guide is to show you what you need to consider when working out how much it costs to run a hot tub.

Read Our Guide To Best Inflatable Hot Tub UK HERE
Hot Tub

How to run a hot tub economically

In short, if you invest in a high-quality hot tub, think about where you site it and take good care of it, you will get the most economical use out of it.  Here are some specific tips.

When you buy a hot tub, focus on the core features

The core features are the build quality and the quality of the components, in particular the heater and pumps.  If you’re buying a hot tub with jets, then look for air-induction jets as these are the most economical. 

Remember that these are the features which will really make a difference to how well your hot tub functions, how long it lasts and how economically it runs.  Fun extras such as lights and music can be added separately if you wish.

Think about where you site your hot tub

When thinking about where to site your hot tub, think about where is best for the tub, then think about what you can do to make the place more convenient for the people using it.  Your first priority is to find a place which can support the weight of a hot tub when it is full of water.  A useful guideline is to think about whether your intended site could support the weight of a car.  If so, it’s a possible choice. 

You need to make sure that the area underneath your hot tub is smooth and flat.  This is both to protect your hot tub and to make sure that the water level is even!

You also want your hot tub to be out of the wind, but think carefully about what you use for a windbreak.  For example, if you site your hot tub next to trees, then it could be damaged by the debris which falls from them.  It’s best if you can site your hot tub near a wall or a fairly solid fence.

Remember, you can do a lot to add to the comfort and convenience of your users by putting your hot tub under a gazebo.  This will give them a place to change, extra privacy and so on. 

Anywhere you can safely put a hot tub will almost certainly be perfectly suitable for a gazebo, so, in short, focus on finding the best place for your hot tub, rather than the most convenient place for the people who use it.

Use a floor protector as well as a cover

The most obvious way a hot tub loses heat is through being left open.  The less obvious way, however, is through heat being sucked out onto a cold base.  Think about how it feels when you put a bare foot on a cold bathroom tile.

You can buy proper floor protectors for hot tubs and they are a good idea if you can get them easily and for a reasonable price.  Alternatively, just put down some form of insulation to protect the base of your hot tub from the cold ground.

Think about how you use water

First of all do you really need to fill your hot tub right up to the maximum water line?  Could you make do with the minimum water line or somewhere in between?

Secondly, you might want to consider filling your hot tub with hot water.  Make sure you put a thin layer of cold water in first and then keep any additional water to a maximum temperature of 40°C.  This will reduce the length of time it takes for the initial heating.

Thirdly, consider the temperature at which you run your hot tub.  Obviously, you do want it to be warm enough to be comfortable for you (and for you to get any medical benefits), but even just turning it down slightly can do a lot to reduce your running costs.

Keep your water heated between uses

Unless you are going away for a long time, it generally makes more sense to keep the water heated between uses than to switch off the heating and reheat the hot tub each time you want to use it.  Depending on your electricity tariff, you might want to see if you can synchronize your heating and filtering cycles for your designated off-peak hours.

If you are going away for an extended period, then you might want to consider draining your hot tub unless you can have someone check on it regularly.  This is as much for safety as for economy.  If, however, you do decide to keep your hot tub running, see if there is an energy-saving setting or think about whether you could turn down the temperature a bit, to keep the hot tub just “ticking over” while you’re away.

Maintain your hot tub

Check your hot tub for damage and if you see any deal with it quickly before it becomes serious.  Keep your hot tub clean.  Think about vacuuming your floor, you pick up large bits of debris before you run the vacuum over it.  On the same logic, if large bits of debris get into your hot tub, pull them out by hand (or with a net) to make life easier for your filters.

Similarly, clean your filters regularly so they perform at their best.  This not only prolongs their life but makes life easier for your pump.  If your filters are full of debris then the pump will have to work harder to circulate the water.  This not only means it uses more electricity but can also shorten its working life.

Clean the walls of your hot tub.  This helps to keep the water clean naturally and hence reduces your need for chemicals.

Shop around for chemicals/filters

This may seem like a small point, but small points can make a difference.  Shop around to make sure that you are getting the best, possible deal on consumables such as chemicals and filters.  You might even want to consider buying them when they are on special offer and storing them until you need them.

On that note, remember that chlorine works most effectively when the pH level of the water is between 7.2 and 7.6.  If you check this before you add the chlorine, you can avoid wastage.

In short

A hot tub is an investment purchase, but it can be a surprisingly affordable one.  If you site it in a suitable location and maintain it properly, your running costs will be kept to a minimum.  They can be justified even if you only use a hot tub for recreation rather than needing it for its medical benefits.

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