Running costs updated 1 October 2026. Every electricity figure on this page is costed at the Ofgem price cap average electricity unit rate of 26.32p per kWh, which applies from 1 October to 31 December 2026. Your own tariff may be higher or lower, so check your latest bill before relying on these numbers.
Most inflatable hot tubs go from box to bubbling in under an hour of actual work. The heating is what takes the time: often a day or more from cold tap water. This step-by-step guide is for UK gardens.
Always follow your manual. This guide gives general UK guidance, drawn from manufacturers' instructions and standard water-care practice. It is not a substitute for your hot tub's own manual or for a qualified electrician. Where the two disagree, your manufacturer's instructions win.
The short answer
Prepare a level base, lay the mat, inflate the tub, connect the pump, fill it with a garden hose, add your first dose of chemicals, then heat it with the insulated lid on. Expect roughly 14-28 hours to heat from cold tap water to 38°C.
Before delivery day
- Choose and prepare the base. See what to put under an inflatable hot tub.
- Check you have an RCD-protected outdoor socket within reach of the pump cable. Do not use an extension lead.
- Get a hose long enough to reach, plus test strips and a sanitiser. See hot tub chemicals for beginners.
Step by step
- Lay the ground mat on a clean, level surface with no stones.
- Unfold the tub with the valves positioned towards the socket.
- Inflate using the pump's inflation setting or the supplied hose until the walls are firm. Do not over-inflate on a hot day. Air expands as it warms.
- Connect the pump and fit the filter cartridges. Hand-tighten the connectors.
- Fill with the hose to the marked fill line. Some owners use a hose pre-filter to reduce minerals and debris.
- Switch on the filter and heater, set the temperature and fit the lid and straps straight away.
- Add the first chemicals once the water is circulating. Balance alkalinity and pH, then add sanitiser.
- Wait for it to heat, then test again before anyone gets in.
How long does it take to heat, and what does it cost?
Inflatable heaters typically raise the temperature by about 1-2.5°C an hour. Our shortlisted models state figures in this range, such as the Nordivale at 1-2°C an hour. Heating 800 litres from about 10°C tap water to 38°C means a 28°C rise. That takes roughly 14-28 hours depending on the heater, the weather and how well the lid fits.
| Item | Figure |
|---|---|
| Energy to heat 800 litres by 28°C (theoretical minimum) | About 26 kWh |
| Cost at 26.32p per kWh | About £6.86 |
| Real-world cost | Higher, because some heat is lost while it warms, especially on cold or windy days |
Calculation: 800 litres × 28°C × 1.163 Wh per litre per °C ≈ 26 kWh. This is physics, not a measured test.
After that first heat-up, daily running costs are what matter. Model yours with the hot tub running cost calculator.
Tips that save money from day one
- Heat with the lid on and the straps done up, out of the wind if you can.
- Use an insulated mat. Heat loss through the floor is easy to forget.
- Set a sensible temperature, such as 37-38°C, rather than the 40°C maximum.
- Fill on a mild day if you have the choice. Tap water is warmer in summer.
Do you need planning permission?
In most UK homes, a portable inflatable hot tub in the back garden does not need planning permission. Listed buildings, flats, rented homes and leaseholds can have their own rules. Check your lease or tenancy agreement, or ask your landlord or local council if you are unsure.
Not sure which tub yet? Start with our hot tub buying guide or compare models on the best hot tubs UK page.
The BestPicks UK hot tub guides
Choosing one
- Hot tub buying guide
- Are inflatable hot tubs worth it?
- Lay-Z-Spa vs CleverSpa
- Inflatable vs hard-shell hot tub
- How long an inflatable hot tub lasts
Setting up
Running and looking after it
- How much a hot tub costs to run
- Hot tub chemicals for beginners
- How often to change hot tub water
- Should you empty a hot tub over winter?
- Using a hot tub in freezing weather
Compare models in our best hot tubs UK guide, or work out your bill with the hot tub running cost calculator.
Frequently asked questions
How long does it take to set up an inflatable hot tub?
Usually under an hour of work to inflate, connect and start filling. Heating from cold tap water then typically takes around 14-28 hours.
Can I fill my hot tub with hot water to speed it up?
Some owners top up with warm water from the house, but check your manual first. Many advise against very hot water, and filling at scale from a domestic boiler is slow.
Can I use an extension lead for an inflatable hot tub?
Most manufacturers say no. Use an RCD-protected outdoor socket within reach of the pump cable. Have one fitted by a qualified electrician if needed.
When can I get in after setting up?
Once it has reached temperature and your test strip shows sanitiser and pH in range.
