Hot Tub Running Costs UK: What You'll Actually Pay

Running costs are the question nobody asks loudly enough before buying a hot tub — and the source of most buyer's regret when the first electricity bill arrives. The honest answer is that a hot tub will add meaningfully to your energy bill, the amount depends significantly on your choices, and with the right setup the ongoing cost is genuinely manageable.

This guide uses current UK electricity rates — approximately 25p per kWh based on the Ofgem price cap in early 2026, though your actual tariff may vary — and real-world usage data to give you figures you can actually plan around. We cover average monthly costs, the difference between 13A plug-and-play and 32A hardwired models, how a heat pump changes the calculation, what drives your bill up, and how to bring it back down.

All figures assume a modern, well-insulated hot tub with a proper thermal cover used consistently. Poorly insulated older models or tubs left uncovered can cost considerably more.

Average Monthly Running Costs

A modern, well-insulated hot tub maintained at 38°C and used two to four times per week will cost most UK owners between £40 and £85 per month in electricity. That is a wide range, because the variables that determine your bill are significant. Here is a practical breakdown by scenario:

The two biggest levers in that table are insulation quality and whether you have a heat pump — more on both below. But first, a note on what drives the underlying energy consumption.

A hot tub's energy use splits into two distinct costs: maintenance heating (keeping the water at temperature when not in use) and recovery heating (reheating after use, when the temperature drops). Maintenance heating is the constant baseline — your tub's heater cycling on and off throughout the week to counteract heat loss. Recovery heating is the burst of energy needed after a session when cooler bodies, jets, and ambient air have drawn heat out of the water.

Between sessions, a well-insulated tub loses roughly 0.5–1.5°C per day in UK conditions. In winter, with ambient temperatures near freezing, that loss can reach 2–3°C per day without a quality cover. Recovering each degree of temperature costs approximately 0.5–1 kWh depending on your tub's volume and heater efficiency — at 25p/kWh, that is 12–25p per degree. It adds up quickly without a good cover.

13A vs 32A: The Real Difference in Running Costs

The 13A vs 32A distinction is one of the most misunderstood aspects of hot tub ownership in the UK. Many buyers assume that 32A (hardwired) models are inherently more expensive to run than 13A plug-and-play models because they draw more power. The reality is more nuanced.

A 13A socket delivers a maximum of 3,120W at 240V — in practice, plug-and-play hot tubs use a 1–2kW heater to stay within safe limits, reserving power budget for pumps and lighting. A 32A circuit delivers up to 7,680W; hardwired hot tubs typically use a 3kW heater.

Here is why that does not straightforwardly mean 32A costs more to run:

The 32A heater's faster recovery means it runs for a shorter period per degree of temperature recovery. A 13A tub running its 2kW heater for 3 hours to recover 3°C uses the same energy as a 32A tub running its 3kW heater for 2 hours — but the 32A tub reaches temperature more quickly and is ready for your next session sooner.

For light users (once or twice a week), the difference in monthly bills is modest — perhaps £15–£25 more per month for a 32A model. For daily users, the 32A tub's faster recovery and heat pump compatibility often make it the cheaper option over a full year. The real cost advantage of hardwired models is not in the heater itself — it is in what you can add to the system.

How Heat Pumps Cut Your Costs

An air source heat pump for hot tubs is the single most effective way to reduce running costs, and the financial case is strong enough that for any owner planning to use their tub regularly, it warrants serious consideration from the outset.

Here is the core principle. A conventional electric heater converts 1kW of electricity directly into 1kW of heat — a Coefficient of Performance (COP) of 1.0. A heat pump extracts ambient heat from the outside air and uses electricity to move and concentrate it. A quality inverter heat pump achieves a COP of 4–6 in typical UK conditions, meaning each 1kW of electricity input delivers 4–6kW of heat output.

Applied to hot tub running costs, this translates into the following:

Return on Investment Calculation

A quality inverter heat pump for a domestic hot tub costs between £900 and £1,600 supplied and installed. Using a mid-point saving of £575 per year:

• £900 heat pump → payback in approximately 19 months
• £1,200 heat pump → payback in approximately 25 months
• £1,600 heat pump → payback in approximately 33 months

After payback, the heat pump continues saving you £460–£690 per year for as long as it operates — typically 10–15 years with proper maintenance. On a 10-year ownership horizon, a £1,200 heat pump delivers a net saving of approximately £4,500 over running an electric heater alone.

A few caveats worth understanding. Heat pump COP falls in very cold conditions — below 5°C ambient air temperature, most units drop to a COP of 2–3 rather than 5–6. This means winter running costs are higher than the annual average suggests, and during the coldest periods your electric heater may operate as a supplement. Inverter-driven heat pumps (as opposed to on/off models) handle this more gracefully by modulating output rather than cycling on and off. For UK conditions — where true sub-zero temperatures are relatively infrequent — a good inverter model will maintain a favourable COP for the majority of the year.

Heat pumps also require space alongside the hot tub (typically 0.5–1m clearance for airflow) and are not compatible with all 13A plug-and-play models. If heat pump pairing is part of your plan, confirm compatibility with your hot tub model before purchase. Most hardwired 32A hot tubs include heat pump connection points as standard.

Factors That Affect Your Bill

Insulation Quality

This is the most significant variable after the heater/heat pump question. Modern hot tubs use full-foam insulation, where expanding polyurethane foam fills every cavity in the cabinet. This dramatically reduces heat loss compared to partial-foam or air-gap designs used in older or budget models. When comparing tubs, ask specifically whether the cabinet uses full-foam or partial-foam insulation — the difference in annual running costs can be £200–£400.

Cover Quality and Discipline

A quality thermal cover — 10cm tapered foam core, sealed in marine-grade vinyl — can reduce heat loss by up to 75% compared to a thin or damaged cover. The cover is arguably more important than the cabinet insulation, because heat rises and the water surface is the primary loss point.

Cover discipline matters equally: every minute the cover is off and the tub is not in use costs money. The practice of removing the cover 10 minutes before you want to use the tub (rather than immediately before) is a small habit with a meaningful cumulative effect. A heat retention blanket — a floating foam disc that sits directly on the water surface beneath the hard cover — adds another layer and is a cheap, effective upgrade for anyone in a colder location.

Set Temperature

Every degree of target temperature adds to your maintenance heating cost. The difference between maintaining a tub at 38°C versus 40°C is small per day, but across a year — particularly in winter — it accumulates. Many regular users set their tub to 36–37°C in summer and only push to 40°C for specific occasions. Some go further and use economy mode to let the tub drop to 20°C between weekly uses, then schedule a reheat — this works well for predictable users but less so for spontaneous ones.

Ambient Temperature and Location

The greater the difference between your target water temperature and the outside air, the faster your tub loses heat and the more the heater runs. A tub in a sheltered, south-facing garden in the south of England will cost less to maintain than the same tub in an exposed, north-facing spot in Scotland. Windbreak planting, fencing, or a pergola structure around the tub meaningfully reduces wind chill losses. Each 5°C reduction in effective ambient temperature through sheltering can save £5–£15 per month in winter.

Usage Frequency and Jet Use

Counterintuitively, using your hot tub more frequently can reduce running costs per session, provided your tub is well insulated. This is because a tub held at temperature requires less energy per session than one allowed to cool significantly between infrequent uses. The energy cost of reheating from 30°C to 38°C is substantially greater than the maintenance cost of holding at 38°C continuously.

Running jets also draws power — a 2HP pump uses approximately 1.5kW when running. A one-hour session with jets running throughout adds roughly 37p to the session cost (1.5kW × 60 min × 25p). This is modest in isolation but worth noting for heavy users running multiple pumps simultaneously.

Tips to Reduce Running Costs

• Fit a heat pump. As detailed above, this is the single highest-impact action. Inverter heat pumps repay their cost within two to three years for regular users and continue saving money for a decade beyond that.
• Upgrade your cover if it is more than five years old. Covers degrade over time — the foam absorbs water, adding weight and losing insulation value. A new quality cover typically costs £150–£300 and pays for itself within one to two years through reduced heating costs.
• Add a floating thermal blanket. These cost £30–£80 and reduce surface heat loss by an additional 30–40% when placed under the hard cover. Particularly effective in winter.
• Use a smart timer or economy mode. Most modern hot tubs allow you to set maintenance temperature (e.g., 35°C when not in use) and schedule pre-heating before your usual session times. Dropping the maintenance temperature by 3°C saves approximately 10–15% on maintenance heating costs.
• Consider a time-of-use electricity tariff. Tariffs like Octopus Agile or Economy 7 offer substantially cheaper off-peak rates (sometimes below 10p/kWh overnight). Scheduling your tub's main heating cycle to run between midnight and 6am can cut heating costs by 30–50% for users with compatible smart controls. Worth significant consideration if you use your tub daily.
• Shield the tub from prevailing winds. A fence, hedge, or pergola that blocks wind from the tub's exposed sides can reduce heat loss by 10–20% in winter.
• Keep the water chemistry balanced. Scale build-up on heating elements reduces their efficiency over time. Regular water maintenance is not just about water quality — it extends heater life and maintains energy efficiency.

Is a Hot Tub Worth It?

Running costs are real, and it is right to factor them in honestly. But the question of whether a hot tub is "worth it" depends on what you are weighing them against.

For context: the average UK gym membership costs £40–£60 per month. A regular professional massage costs £50–£80 per session. A weekend away costs several hundred pounds. A well-run home hot tub, used three or four times a week, costs £45–£80 per month all-in — and it is available at 10pm on a Tuesday without a booking, a drive, or a queue.

The evidence on hot tub health benefits — cardiovascular improvements, stress and cortisol reduction, muscle recovery, improved sleep quality — is substantive. The evidence that these benefits require consistent, frequent access is equally clear. A hot tub in your garden, available without friction, is categorically different from a facility you visit occasionally.

The owners who feel a hot tub was not worth the cost are almost always those who underestimated running costs and bought under-insulated models without a heat pump. The owners who use theirs daily and have a heat pump fitted rarely question the value — the marginal cost per session at £0.30–0.50 with a heat pump is negligible against the lifestyle benefit.

The practical conclusion: a well-chosen hot tub with decent insulation and a heat pump fitted from the outset costs approximately £15–£30 per month to run for a regular user. That is a reasonable price for what it delivers. A poorly chosen one without a heat pump and with a thin cover can cost £100–£150 per month — and those are the stories that give hot tub running costs a bad reputation.

The Steam & Oak Hot Tub Buying Guide covers insulation standards, heat pump compatibility, and what to look for in a cover across our full range — including the running cost implications of each choice. When you are ready to browse, our full range of hot tubs and heat pumps is available at steamandoak.co.uk, with free UK delivery on all orders.

Electricity rate used throughout: 25p/kWh, reflecting the Ofgem standing charge unit rate in early 2026. Actual rates vary by supplier, tariff, and region. All running cost figures are estimates based on typical usage patterns and modern hot tub insulation standards — your actual costs will vary.