How much does a hot tub cost to run per month in the UK?

By the Fonteyn UK team · Outdoor living advisers at Fonteyn

A hot tub costs around £25 to £45 a month to run in the UK when it is well insulated and kept warm. That works out at a smart, manageable daily figure for year-round use.

The exact amount shifts with the size of the tub, how well it holds heat, and the weather outside. Here is how the maths actually adds up.

How much does a hot tub cost to run per month in the UK?

The single biggest factor in the bill is electricity, and the UK average sits at 24.67p per kWh, rounded to roughly 25p in everyday terms. That rate comes from the energy price cap that Ofgem set for the period running from 1 April to 30 June 2026, which puts a typical household on around £1,641 a year for gas and electricity together. Knowing the unit price turns the monthly cost from a guess into simple arithmetic.

The maths is straightforward. A well-insulated tub uses somewhere between 3 and 6 units of electricity a day to hold its temperature and run its pumps. At about 25p a unit, that lands between 75p and £1.50 a day. Across a month, the lower end sits near £23 and the upper end near £45, which is where the headline figure comes from. A morning coffee habit lands in much the same place.

In the Leicester showroom, the advisers find that this number surprises people in the nicest way, because the running cost spreads across daily use the whole family enjoys. A tub that holds heat well behaves predictably month to month. The figures here assume a quality cover and modern insulation, which is exactly what the next sections build on.

Where does the energy in a hot tub actually go?

Picture the energy splitting into two jobs. The first job is bringing fresh water up to 38 degrees and then holding it there, and that accounts for roughly four-fifths of everything a hot tub uses. The second job covers the moving parts: the small pump that circulates and filters the water around the clock, the stronger pumps that power the jets while someone is in the tub, and the lights that set the evening mood.

Once the water is warm, holding it there is gentle work, because a good cover and thick insulation trap most of the heat between sessions. The heater then tops up only the small amount that escapes. This is why two tubs of the same size can show very different bills: the better-insulated one asks the heater to do far less.

That is where Fonteyn's three-layer insulation earns its keep. It packs dense foam against the shell, a heat-reflecting barrier in the middle, and solid outer panels around the cabinet, so warmth stays in the water rather than drifting into the garden. Fonteyn's own product data describes this build across the Passion Spas range. The advisers explain it simply in the showroom: the harder the cabinet works to hold heat, the less the heater has to.

Is a hot tub cheaper to run in summer than in winter?

British weather sets the pace for the heater. In summer the air is mild, the water loses very little warmth, and the heater works in short, gentle bursts to hold 38 degrees. That is why the warmer months sit at the lower end of the range. The tub stays ready for a spontaneous evening soak while the meter barely moves.

Through autumn and winter the air cools, so a little more warmth escapes the surface and the heater steps in more often to top it up. The bill nudges upward, yet a well-built tub keeps the difference modest rather than dramatic. Year-round use is one of the real joys of owning a hot tub in the UK, and a steaming soak under a frosty sky is a genuine highlight of the colder months.

This is the moment Fonteyn's All-Weather heat pump shines. It pulls warmth from the outdoor air and keeps performing in cold British weather down to minus 20 degrees, and its DeFrost function keeps it clear and working when the temperature dips. Because a heat pump delivers several units of heat for each unit of electricity it draws, it carries the winter heating load at a smart, manageable cost. The advisers in Leicester point to it whenever someone plans to use their tub right through January.

Which technology keeps hot tub running costs low?

Three pieces of technology do most of the heavy lifting on running costs. Strong insulation around the shell and cabinet keeps warmth in the water. An air-source heat pump generates heat far more efficiently than a standard element, drawing several units of warmth from the air for every unit of electricity it uses. And an intelligent control system lets the tub idle gently when nobody is using it, then bring the water up in good time for an evening soak.

According to Ofgem's 2026 price cap figures, the unit rate stays the dominant lever on the final bill, so anything that reduces the units used shows up directly in the monthly cost. That is the appeal of efficient heating: fewer units for the same warm water. Industry testing of air-source heat pumps consistently shows them outperforming direct electric heating across a full year.

Fonteyn brings these together in the Green Collection. The All-Weather heat pump handles the warming, the three-layer insulation holds it, and the eco mode keeps everything ticking over gently between soaks. An AutoLock cover seals the surface and locks down securely, which keeps the heat in and gives families peace of mind between sessions. The advisers describe the combination as the engine room behind a hot tub that feels great value to run all year.

Grizzly Spas Spa Green Kodiak

Green Collection hot tub with an All-Weather heat pump and three-layer insulation for low year-round running costs.

Save £2,909

£9,590 £12,499

View the Spa Green Kodiak

How do everyday habits shape the monthly cost?

The way a hot tub is used day to day shapes the bill as much as the model itself. Keeping the water at temperature is the smartest approach for most owners: once a well-insulated tub is warm, holding 38 degrees takes very little energy. Letting it cool right down and reheating from cold each time asks the heater for a much bigger effort, so a steady temperature is the great-value habit.

Timers and eco settings make this effortless. Running the filtration pump on a schedule during off-peak hours keeps the water clean while the meter is at its quietest. An eco or economy mode lowers the background heating during the night and brings the water back up in good time for the evening. Heading off on holiday for a couple of weeks? A holiday setting is ideal, easing the tub into a lower idle that is quick to wake up on return.

In the Leicester showroom, the advisers walk new owners through these settings before delivery, so the tub arrives already tuned for smart running costs. The most common question Fonteyn hears is whether leaving the tub on is the sensible choice, and for a well-insulated model the answer is a confident yes. Small, consistent habits keep the bill comfortably in the lower half of the range.

What should you look for in an energy-efficient hot tub?

A handful of features separate an efficient hot tub from a thirsty one. The insulation matters most, so a tub packed with dense foam or built in layers around the shell and cabinet holds its warmth between soaks. A close-fitting, heavy cover seals the surface, which is where most heat would otherwise escape overnight. The heating method comes next, with an air-source heat pump leading the way on efficiency.

The controls round it off. A programmable system with eco, economy and holiday modes lets the tub match its energy use to how the household actually lives, idling quietly when nobody is in and warming up in good time for a soak. These are the features the advisers point to first when a family wants year-round use at a comfortable cost.

Fonteyn's Beast Frost Core is built around exactly this thinking, pairing strong insulation with frost-ready heating so it keeps performing through a cold British winter at a great-value running cost. Seeing the insulation and covers in person at the Leicester showroom makes the difference easy to understand, and the advisers are happy to talk through real running figures for each model.

Fonteyn Beast Frost Core

Frost-ready hot tub with strong insulation, built to keep performing efficiently through cold British winters.

£4,160

View the Beast Frost Core

Keeping the water balanced also helps the tub run smoothly and the equipment last, and a tidy water care and filter routine sits neatly alongside the energy habits above. Owners who want to top up supplies will find everything from filters to balancers in the hot tub parts and water care range, while the full collection of spas and hot tubs shows the energy-efficient models side by side.

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