How much will the hot tub cost to run?
It's difficult say as many factors effect the cost, mainly the temperature of the tap water being used to fill the tub and the outside air temperature.
It's possible to estimate the cost using a worst case (ie mid winter with freezing air temperatures):
The pump which heats the water is powered by electricity and consumes approx 2000 watts of power. Currently the electricity price cap (at 1 Jan 2026) is around 27 pence per unit, so running the 2000 watt pump for 1 hour will cost 54p.
The temperature of tap water in January is usually around 10c and it takes the pump around 1 hour to raise the temperature by 1.5c, so it will take around 20 hours to reach 40c. This will cost 20 x 54p, so £10.80
In mid summer it won't cost as much as the tap temperature can be around 20c, also the hot tub water temperature is unlikely to be needed as hot as 40c, 37c should be fine (or lower if we have very hot weather) so this will take the pump 11 hours to heat the water, therefore costing £5.94.
During Autumn & Spring the cost will fall somewhere between £6 and £11.
Once the water is up to temperature, then the pump needs to maintain it. The more heat that is lost from the water then the harder the pump has to work. The main factors that will lower the water temperature are the outside air temperature, the number of people using the tub and the amount of time it's in use.
If, during the Winter the pump is on for 1 hour and off for 1 hour, then it's costing £6.48 per day. In the summer it may be on for 1 hour and off for 3 - in this case it's costing £4.32 per day. If in extremely cold weather the pump is on the whole time, then the absolute maximum it can cost is £12.96 per day (but this is unlikely to ever happen).
So in summary - to heat the water initially it should cost somewhere between £6-£11. From then on it should cost between £4.30-£6.50 per day.
Of course, if you have solar panels and/or battery storage or an overnight electric rate (that lowers the unit rate from 28p to around 6-8p per unit then running costs will be much less.
These costs can be lowered! We do offer a thermal jacket that completely surrounds the tub to keep it warm. It's estimated that this prevents upto 50% heat loss (and therefore 50% of the cost). We charge £6 for the jacket (for the duration if the hire) so it's likely to pay for it's self, especially if you have the tub in Winter or for more than a couple of days in the summer.
You can reduce the energy costs further by not filling the tub fully with water (as the more water then the longer it will take to heat). You can also put your own old blankets or duvets over the the tub when it's not in use and this will also help a lot to keep it warm.