Published 5 November 2026 · price-cap figures valid to 31 December 2026
Can You Run a Hot Tub off Solar Panels? The kWh Maths for a UK Garden
A hot tub is one of the biggest electrical loads a garden has, which makes it a natural question for anyone thinking about solar. The honest answer: a garden array can cover a hot tub in summer and a fraction of it in winter. Here is the maths, using a manufacturer's published figure and real UK solar output. Solar Panels for Gardens is an independent information and enquiry service, not an installer; we reply by email.
How much electricity a hot tub uses
Jacuzzi, one of the largest makers, says that "on average, our UK customers use around 5kWh per day". Your tub may use more or less depending on its insulation, its cover, how hot you keep it, how often you use it and the weather. The tub's own spec sheet or a plug-in meter will tell you your figure; we use 5 kWh a day below as the worked example.
Hot tub running costs
At 5 kWh a day and the Ofgem price-cap rate of 26.32p per kWh (the GB average for 1 October to 31 December 2026, with no VAT on household electricity in that period), a hot tub costs about £1.30 a day, about £40 a month, or about £480 over a year at that rate. The cap changes every quarter, so recalculate with your own tariff from 1 January 2027.
What a garden array makes, summer and winter
| Garden array (south, 35°) | A June day | A December day | A year |
|---|---|---|---|
| 1.8kWp, about 4 panels (the 9 m² permitted-development size) | about 7 kWh | about 2 kWh | about 1,750 kWh |
| 4kWp, about 9 panels (needs planning permission in a garden) | about 15.5 kWh | about 4.4 kWh | about 3,900 kWh |
Figures are from the European Commission's PVGIS tool for central England (Leicester) at 14% system losses: 3.88 kWh per kWp on an average June day and 1.10 in December.
How many solar panels to run a hot tub
Against 5 kWh a day, a 1.8kWp array covers a good summer day with some to spare, and about 40% of a December day. To cover a December day you would need roughly 4.5kWp, which is about 22 m² of panel: over the 9 m² cap for stand-alone garden solar in England, so it would need planning permission. Timing matters too: a hot tub heater runs when the water cools, often overnight, so without a battery much of the solar output is exported rather than used by the tub.
What it saves
If a 1.8kWp array supplies the tub with about 1,000 kWh a year that would otherwise come from the grid, that is worth about £260 at 26.32p; the rest of its output is exported under the Smart Export Guarantee at around 12–13p for the better fixed rates. A garden array of that size costs £2,200–£3,500 installed; see garden solar costs for bigger sizes, based on the government median of about £1,550–£1,600 per kW.
Solar hot tub heaters are a different thing
A "solar hot tub heater" is usually a solar thermal collector: a dark panel or coil that warms water pumped through it. It can add warmth on sunny days, but it does not make electricity, run the pumps or replace the tub's heater. Solar PV panels make electricity for everything the tub does.
Where to put the panels
A south-facing ground-mounted garden array makes the most per panel and is often permitted development up to 9 m². If the tub sits under a pergola or canopy, the panels can form its roof, though the planning rules for that are less clear-cut.
Hot tub and solar questions
Can you run a hot tub on solar panels?
Partly. A hot tub that uses about 5 kWh a day (the average Jacuzzi reports for its UK customers) could be covered on a sunny June day by a garden array of about 1.8kWp, but in December the same array makes about 2 kWh a day, so the mains supplies most of the winter load.
How many solar panels do you need to run a hot tub?
For about 5 kWh a day in central England: around 4 panels (1.8kWp) covers it on a good summer day; covering a December day would need roughly 4.5kWp, which in a garden is over the 9 m² permitted-development cap and needs planning permission.
How much does a hot tub cost to run?
At 5 kWh a day and the Ofgem price-cap rate of 26.32p per kWh (1 October to 31 December 2026), about £1.30 a day, or roughly £40 a month. Your own tub's figure and tariff will differ.
What is a solar hot tub heater?
A solar hot tub heater is usually a solar thermal collector that warms the water directly, not a solar panel that makes electricity. It can lift water temperature on sunny days but does not run the pumps or replace the electric heater.
Want to power a hot tub with solar?
Tell us the plot size, which way it faces and what shades it. You will get the options back by email: array size, likely output and what to ask an installer.