Your complete guide to hot tub temperature settings

How hot is a hot tub sounds like it could be a philosophical question, but for most owners it rapidly becomes one that requires a real answer.

How hot is a hot tub sounds like it could be a philosophical question, but for most owners it rapidly becomes one that requires a real answer. 

We are asked about temperature settings frequently. And we don’t want you to have to wait for an answer, so here is our best overall advice: 

  • There is no specific, set “one size all” temperature for hot tubs. It’s personal Look at it this way, you get to find your ideal hot tub temperature.
  • Most people prefer to use their hot tub in the temperature range of 37C-40C.
  • Our general advice is to start at 37C and adjust up or down from there.
  • The top temperature for a hot tub is 40 degrees Celsius. That is the maximum temperature for hot tubs.

That’s what we tell customers about hot tub water temperatures when asked in our stores. We wrote this because we are asked about “correct” temperatures so frequently. In this article, we will explain in more detail:

  • What temperature should a hot tub be?
  • What temperature should I leave my hot tub on overnight?
  • How long do hot tubs take to heat up?
  • How much does it cost to heat a hot tub?

Hopefully, by the end, you’ll have a strong sense of temperature settings for your hot tub. 

What temperature should a hot tub be?

Here’s the quick answer: We find that most people find 37C is the most comfortable for warm water, although some will go up to 40C, which is the highest setting allowable.  

The real answer though is this: There are no should in the world of hot tubs. Finding out what temperature you like is one of the joys of ownership: you get to find your own perfect hot tub temperature. It also may change based on your ambient temperature: If it’s cold outside, you may want a slightly warmer experience. If it’s warm, you might want to match that temperature. 

When I get my hot tub for the first time, what temperature should I set it at? 

What we recommend to any new buyer is to start with 37C and see if you prefer warmer or colder than that. This is a safe hot tub temperature to begin experimenting with. Our best advice is to try a cooler temperature and work your way up, then start too hot and work your way down. Too hot will make it difficult to actually get in and enjoy the hot tub, which defeats the purpose of owning one! 

What temperature should I leave my hot tub on overnight? 

We recommend you don’t get caught up in changing temperatures. So if you generally use it at 37C, we’d suggest leaving it at that. Why do we not advise changing? 

What we have found is that the heating and re-heating will wind up costing you more than it would if you left it at one set temperature. Hot water tanks in houses work the same way: It’s cheaper to set it at one temperature and hold it, rather than letting the water cool and then heat it again. 

What is the most efficient temperature for a hot tub? 

There’s no one set temperature here. The answer is the same as above: It’s better to keep a consistent temperature than yo-yo it up and down, which will make your heater work harder adjusting, and cost you more money. 

Should I lower the temperature of my hot tub when I go away? 

It depends how long you will be gone. If you’re going to be gone six weeks or more, you may see some savings by lowering it down to around 30C. We advise this temperature because you don’t want to drop it so low that you will use tonnes of power to bring it back up to a usable temperature again. 

Should I shut my hot tub jets off when I go away?

Our answer here is no. The jets are important to run to keep the water circulating and moving through your filters. The cost here is not expensive as the circulation pump is not a major draw on your utility costs. And it will keep your water cleaner this way. 

How long do hot tubs take to heat up? 

If you’re starting with a newly filled tank, it can take anywhere from 18 to 24 hours to heat up your hot tub. 

  • The largest factor here is the temperature of the ambient area around you. If it’s cool out and you’re trying to get the hot tub to 40C, it will take longer than if it’s 25C outside and you’re trying to reach 37C.
  • The temperature you’re trying to reach. It may be only a couple of degrees, but to get from 35C to 40C can take an hour, especially if it’s cold outside.
  • The size of the hot tub. A full seven-seat hot tub will take longer than a small three-seater, but not as long as you might think, as it will have stronger heaters.

How much does it cost to heat up a hot tub? 

We know this is a big area of interest for most people. So we have an entire article breaking down monthly costs, which includes heating here. We estimate the average heating cost is about £2.50 per day for a hot tub (this is with a tub heated to 37C and using the tub for an hour a day).

Energy efficiency is key when building a hot tub. Hydropool’s hot tubs are insulated similar to a triple paned window, in that they are designed to trap heat inside. In this case, they are built to trap the residual heat from the motor inside the hot tub cabinet and use it to to help heat your water. Not every company does this. Many will choose instead to use full-foam insulation, which completely stuffs the cabinet of each hot tub full of insulation. This can work, but it’s actually less efficient than Hydropool’s system (we know because we used to use full-foam in our hot tubs). 

How hot is a hot tub?

We get asked about hot tub temperatures frequently in our stores. It’s a good question! There are several situations that new owners simply don’t know about yet and temperature settings is a common one. 

That’s why we wrote this article, in the hope that it would answer all your questions about temperature settings with your hot tub. Here’s the main answer we give: Most people keep their hot tubs between 37C and 40C, but this temperature setting is entirely up to the person in it. 

Did we miss anything about temperature? If we did, don’t hesitate to let us know. We will be happy to help you out.