Nothing can beat the pleasure of spending time with beloved ones in a hot tub for relaxation. That’s why it’s good to know how long for a hot tub to heat up so you can turn it on in advance before jumping in to enjoy the delight.

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How long for a hot tub to heat up?

Normally, a hot tub needs about 4 hours to heat up but on some occasions, it may require from 3 to 8 hours to do so. There are many factors which affect the heating up time such as water temperature, the location where you put your hot tub, its size, and so on.

In case you’re worried that your hot tub takes too much time to heat up, please use the following rule of thumb to consider having it fixed or just let it be. If the temperature of water in your hot tub increases by about 3 to 6 degrees Fahrenheit per hour, your hot tub is still in good working condition.

What affects the heating up time?

The heating-up time can be altered by many factors. Let’s have a look at them.

1. Water temperature 

Water starting temperature is one of the most important factors that directly affect the heating up time of your hot tub.

Clearly, you will spend a lot of time waiting for the tub to heat up the cold water, which is only just above freezing until it reaches the working temperature.

Correspondingly, initial water with a very warm temperature can help to reduce the amount of time for the whole process.

2. Power of the heater

Based on kilowatt, you can measure the heater’s power rating. The heater with a higher kilowatt rating will heat up the water more quickly.

Theoretically speaking, a heating element with 3 kilowatts ought to heat up the same quantity of water 3 times faster than a heating element with 1 kilowatt.

Obviously, the one with more kilowatts will use more electricity during a shorter period of time.

3. The size of your hot tub

how long to heat a hot tub

The size of a tub also matters. Indeed, it will consume more time to heat up 700 liters of water compared to when the tub has just 300 liters of water inside. So, the bigger your hot tub is, the longer to heat the water up.

One more thing, it is not recommended to use a 1-kilowatt heater to heat a big 700-liter hot tub. You know why, don’t you? Yes, it might take you years to finish the heating-up process, which means you will have to wait years to enjoy the hot tub.

Hence, you should consider not having a hot tub which is too big for your need since it will be a waste of your time and money heating up an unnecessary extra amount of water.

4. Insulation

The quantity and condition of your hot tub’s insulation system also have a huge role to play in both how fast it heats up the water and how well it maintains its heat.

Many old version hot tubs are poorly insulated when compared with the latest standards. What is worse, they will regularly leak away heat. This implies that a hot tub with a poor insulation system will take longer to heat the water up and waste more energy to maintain the heat.

You can easily upgrade your insulation if you doubt that it isn’t up to scratch by filling any voids located underside of your hot tub with foam insulation. This should be done carefully in order to avoid covering vent holes.

5. Ambient temperature

It is true that the ambient temperature also matters how quickly your hot tub can finish the heating-up process.

Let’s say, with the same amount of water, using the same hot tub, you will experience that it takes you longer to completely heat the water in winter than in summer.

We can do nothing to change this factor. So, just keep the notice in mind to have a better preparation before using your hot tub.

Does a hot tub heat up faster with the cover on?


As it is known that hot air flies up, which is a reason to explain how a hot tub cover is responsible for keeping warm air inside and making it easier for the hot tub to boost the heating-up process.

A better version of a hot tub cover can also prevent the heat from escaping while the hot tub is working to heat up the water, which will help you to jump in the water and have a pleasant time more quickly.

Tips for a faster heating time

Below are a few ways that can assist you to improve the efficiency of the hot tub. Complying with these steps might not only speed up the heating time of your hot tub but also reduce the cost of your electricity bill.

Firstly, it is necessary to have an insulated, high-quality hot tub cover that will shut in the heat inside. Be careful with your existing cover if it has cracks or holes because heat is going to get away, so does your time and money.

Whether you want to buy a cover, seek a lockable one that has tapered edges as it will trap the heat up to the hilt.

There is one small thing that not many hot tub users have ever thought of – the landscaping around their hot tub. Well, a sheltered place, where there are walls on 2 or 3 sides and the sun shines for most of the day, will speed up the heating time.

In contrast, a place with the prevailing wind or no direct sunlight will somehow stagnate the process.

Moreover, make sure to service the hot tub routinely if you want to keep every component in fine working order. Not to mention that this will help the heat and hot tub’s water flow freely.

Last but not least, maintenance recommendations and servicing guidelines from your dealer should be followed strictly.

Before leaving

To sum up, I hope that my article has just provided you useful information regarding how long to heat a hot tub. If you haven’t got a cover, get one. If there is the prevailing wind blowing to your hot tub, use something to shelter it.

If you have any tips to fasten the heating time, please let me know.

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