• Jess Court

How Long Does it Take to Heat a Hot Tub

Most times, people ask the question of how long it will take to heat a hot tub. In actuality, it depends on a number of factors, including whether you cover the hot tub, whether it has a powerful heating element or the temperature of the environment.

Hot tubs are a great addition to any house and can be ideal for relaxing after a long day or getting that therapeutic soak. Many hot tub owners sometimes wonder how long it takes for their tub to heat up, while others wonder why it takes so long.

In this article, we will be looking at the time it takes to heat a hot tub depending on these factors, what you should expect, and how to speed up the heating process.

How Long Does It Take To Heat Hot Tub Water?

Most people ask, "how long does it take a hot tub to heat?" That information is dependent on a lot of things. Note that water is a liquid, and liquids happen to heat differently than solids, so they require quite some time to heat. If this is the first time you are heating your tub or following a service or clean up, the time it takes to heat up depends on your tub's water heater. If you have a powerful heater, it will take less time for the hot tub's water to go from cold to the ideal temperature.

Typically, water heats up at five to ten degrees Fahrenheit in an hour. To heat your tub to the right temperature, which is between 100 to 102 degrees Fahrenheit, it can range anywhere from three to eight hours.

Why Does A Hot Tub Take So Long To Heat Up?

The condition of the components of your hot tub, such as the hot tub cover, jets, pump, and water heater, impact how fast it reaches the desired temperature. The hot tub's components should be in good shape to allow heat and water to flow freely through them.

If you place your hot tub outside, the ambient air temperature also affects its heating process. You can simply say that the warmer the environment's temperature, the faster your tub heats up.

What Are The Factors That Affect How Long A Hot Tub Takes To Heat?

Most hot tubs can hold up to 320 gallons of water, which could be a lot to heat up when you are ready for your relaxing soak. So, these are the factors that determine how long it takes to heat up your hot tub.

Base (Starting) Water Temperature

This is an obvious factor, but it still has to be mentioned. The starting temperature of your hot tub impacts how fast your hot tub heats. It is a personal choice to leave your hot tub running all the time, but you should note that it also affects the time it takes to heat.

Ambient (Surrounding) Temperature

Ambient temperature is the measure of the temperature surrounding a particular piece of equipment or asset. This signifies that your hot tub will have a reduced heating time if the air around it is warmer or if the water inside it starts out warm.

If your tub is placed in a windy spot, you can control the air temperature around your tub and reduce the time it takes for your hot tub to heat by taking the following steps;

  • Planting two rows of shrubs as a natural wind barrier

  • Set up a windscreen on the prevailing wind part of the hot tub.

You can also choose to continually elevate the temperature of your hot tub by taking full advantage of the sun's warmth and positioning the tub in a sunny spot.

Tub Insulation

It is important to remember that a tub with proper insulation will retain heat better. Heat can escape through the surface of the water and into the air. It can also leak out of your hot tub cabinet if there are tiny cracks and seams.

The base of the hot tub is another area that could cause the heated water to lose its heat energy. Your hot tub will heat slower if it is on a concrete pad or identical hard surface. You should identify all these leaking spots and insulate accordingly.

Hot Tub Size

Typically, a big hot tub will take more time to heat than a smaller one. Of course, if you own a large hot tub that matches with a 1-kilowatt heater, then you could spend a lot of time waiting for your tub to heat.

Ensure that you do not purchase a hot tub that is way too big for you. You know you are unnecessarily heating a massive body of water if you have a six-seater hot tub and it's only two people in it most of the time. This would increase energy costs and environmental impact.

While a well-designed hot tub would have a heater that matches the water capacity, check to see and find out the heater capacity of your potential hot tub.

Heater Efficiency And Power

Another thing that affects the heating time of your hot tub is the efficiency and power of your heater. The power ratings are measured in kilowatts, and ideally, the higher the rating, the faster it heats up the water.

In theory, this means that a 4-kilowatt heating element will heat water two times faster than a 2-kilowatt heating element. Normally, there is the matter of it consuming more electricity in a shorter period.

Does A Hot Tub Heat Faster With Jets On Or Off?

There is a bit of controversy as to whether leaving the jets on or off affects the temperature of the water. A compromise that stands is to run the jets periodically as the heating goes or turn them on as you get to the final lap of heating so that the warm water is already in circulation before you get in. The jets are advisable because they break up the cold pockets in the pipes.

How Can You Heat Your Hot Tub Faster?

It can be hard to know just long it would take for hot tubs to heat as there are many factors involved. However, you can improve the heating of your hot tub with some simple processes, including keeping the filter clean, finding a nice location for your hot tub, or using a top quality cover.

Use Hot Tub Cover

It is without a doubt that hot air rises, which places hot tub covers as the first line of defence when it comes to retaining the heat ad making it heat up as quickly as possible. You might be wondering why you need a tub cover so badly.

A thermally efficient cover helps to get the water to the required temperature faster and also keeps it there. This signifies that your tub will save energy and money efficiently.

Check to see if your hot tub cover has any cracks or holes, as it is a sign that replacing it is the ideal option. You should not continue using an old hot tub cover as it has already become thermally inefficient and has reduced efficiency.

There are plenty of options to select from, and you can go for the one that surrounds the entire hot tub. These models are made for winter use, but there is no harm in using them to prevent any heat from escaping.

Consider Floating Thermal Blanket

A thermal spa blanket is an insulated floating sheet that is designed to float on the surface of the water. You can picture that as a heavy-duty bubble wrap.

They have a design that allows them to trap heat, particularly during winter. You can provide an extra layer of protection to your hot tub by placing a thermal blanket underneath the cover to prevent heat from escaping through the surface of the water.

For those that are looking to add more insulation than the one provided by the cover, a thermal blanket is a perfect solution. These thermal spa blankets come in different sizes, so you might have to cut them to fit your spa properly.

Routine Maintenance & Servicing

If you are planning to enjoy and have a fun time in your hot tub at home, you should bear in mind that you have to keep it in perfect working condition by regularly maintaining and servicing it. If you notice or realize that any part of your hot tub needs attention, get to it immediately.

Maintenance is not really a thing to enjoy, but it could make a difference in how the system of your hot tub works. You can ruin the materials and elements of your tub if you don't take care of them properly.

Help your spa run effectively, circulate heat better, and finally, reduce the time it takes to heat by;

  • Making sure the jets operate as they should

  • Regularly maintaining the pump

  • Clean the filters and replace the ones that need to be.

Use Standby And Sleep Modes

If you want your hot tube to heat faster, make sure you do not turn it off; rather, you should use the sleep mode. You can utilize the sleep mode if you don't plan to use your spa for some days, as it is a great way for you to conserve energy and also keep your hot tub practically ready to use.

Your hot tub will heat faster when it comes out of sleep mode as it is already at a steady, warm temperature. The sleep mode is a beneficial feature for those looking to save money while keeping the tub well poised for use.

Portable Immersion Heater

Assuming your hot tub has a very slow heating time, and you cannot figure out what else to do to speed up the process, you should opt for a portable immersion heater. This is a small electric device that is plugged and placed into the water. We live in a constantly evolving world, so you must move along with it.

Mixing the features of the immersion heater with the regular heating capacity of your hot tub, you are able to significantly reduce the time taken to get your water to the desired temperature level.

When looking for a portable immersion heater, it is advisable that you shop for one with at least 1500 watts as it will provide you with the best effect.

Is It Safe To Fill A Hot Tub With Hot Water And Heat It?

While you could be losing patience watching your new hot tub heat up, you should avoid filling your hot tub with hot water in an attempt to speed up the process. This is because you will end up damaging the tub's shell as most hot water heaters exceed the heat rating for a hot tub. And it will be too tasking to heat water on your stove top, and it will take you a bit longer than you imagined.

Water that is above 104 degrees could damage your spa. Hot tubs are not designed to withstand scalding temperatures, meaning that they could begin to give way or melt.

While you might eventually speed up the process slightly, it is not worth the risk as you could lose your spa. So, it will be best if you follow the above steps and wait for your tub to heat up the right way.


Most hot tub owners will do anything to reduce the time it takes for their hot tub to heat. Luckily, there are plenty of ways to lower the time your tub needs to get hot like getting a new heater or planting shrubs.

Nevertheless, you can choose any way to tackle the problem of prolonged heating time, what doesn't change is the fact that an average-sized hot tub will take about three to four hours to reach the ideal temperature. But, it is still soothing to know that following the above recommendations can buy you some time and allow you to get to your soaking quicker.



Jess Court

I'm Aqua Warehouse Groups Marketing Officer - overseeing all things news worthy in the hot tub industry, with tips and tricks that are bound to make a splash.

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