Written by: Hot Tub

How Long Does A Hot Tub Take To Heat Up

Ah, the joy of sinking into a hot tub after a long day – pure bliss! But how long does it actually take for your hot tub to heat up to that perfect temperature? The answer to this question depends on various factors such as size, heater efficiency, and starting water temperature.

In this blog post, we’ll delve into those factors affecting heating time and offer some useful tips to help you enjoy your soothing soak even faster.

How Long Does A Hot Tub Take To Heat Up

Factors Affecting Hot Tub Heating Time

The size of the hot tub, starting water temperature, and heater power and efficiency are all factors that can affect how long it takes for a hot tub to heat up.

Size Of The Hot Tub

The size of your hot tub plays a significant role in determining how long it takes to heat up. Larger hot tubs require more water, which means that the heater has to work harder and longer to reach the desired temperature.

For example, heating a small 2-person spa may only take around an hour, while heating a large 6-person capacity model could require several hours.

Keep in mind that certain models have features designed for quicker heating times. For instance, some larger hot tubs come with dual heaters or higher power heaters installed for expedited warming processes without compromising energy efficiency.

Starting Water Temperature

The starting water temperature of your hot tub can affect how long it will take to heat up. If you’re filling the hot tub with cold water, the heater has to work harder and longer to bring the temperature up.

It’s recommended to fill your hot tub with warm or hot water from a hose if possible. This can reduce heating time by up to 50%.

Heater Power And Efficiency

The power and efficiency of your hot tub’s heater can greatly affect its heating time. Generally, the higher the wattage or BTUs (British Thermal Units) of your heater, the faster your hot tub will heat up.

However, a more efficient heater can also help to conserve energy and reduce operating costs in the long run.

For example, an electric hot tub with a 5.5kW heater may take up to 8 hours to heat a large hot tub from cold temperature, while a gas-powered hot tub with 400kBTU output may only take about 1-2 hours on average for a comparably sized spa.

Average Heating Time For Hot Tubs

The average heating time for small hot tubs is between 60-90 minutes, while medium hot tubs can take anywhere from 2-4 hours to heat up, and large hot tubs may take up to 6-8 hours, depending on the starting water temperature and the heater’s power and efficiency.

Small Hot Tubs: 60-90 Minutes

If you own a small hot tub, you’re in luck because it takes the least amount of time to heat up compared to larger counterparts. On average, it takes about 60-90 minutes for a small hot tub with an efficient heater to reach its desired temperature.

However, this heating time can vary depending on other factors such as starting water temperature and ambient air temperatures. Investing in a high-quality thermal blanket or using hot water from a hose also helps speed up the heating process of your small hot tub.

Medium Hot Tubs: 2-4 Hours

Medium hot tubs, typically ranging from 300 to 600 gallons, take longer to heat up compared to smaller ones. On average, it can take between 2-4 hours for a medium-sized hot tub to reach its desired temperature.

Of course, the heating time varies depending on various factors mentioned earlier such as ambient air temperature and starting water temperature. It’s essential to ensure that the lid is closed during this period to reduce heat loss and speed up the process.

Large Hot Tubs: 6-8 Hours

If you own a large hot tub, you’ll have to be a little more patient when it comes to heating up the water. Large hot tubs can take anywhere from 6 to 8 hours or more depending on various factors like the starting water temperature, type of heater used, and ambient temperature around the hot tub.

This long heating time is due to the larger amount of water that needs to be heated compared to small or medium-sized hot tubs. However, investing in a more powerful heater and using a thermal blanket can help speed up this process significantly.

Tips To Speed Up Hot Tub Heating Time

Here are some tips to help speed up the hot tub heating time:

– Use a hot tub cover to trap the heat and prevent any heat loss.

– Consider investing in a thermal blanket or solar cover for even more insulation.

– Start with hot water from a hose instead of starting with cold spa water.

– If possible, consider getting a more powerful heater to reduce the overall heating time.

Use A Hot Tub Cover

Using a hot tub cover can help to speed up the heating time of your hot tub. This is because it helps to trap in the heat that rises from the water, preventing it from escaping into the air.

In addition to speeding up heating time, using a cover can also help you save on energy costs by reducing heat loss when your hot tub is not in use. Furthermore, it will keep debris out of your hot tub during non-use periods, minimizing cleaning efforts and expenses associated with replacing or repairing clogged filters.

Use A Thermal Blanket

Another way to speed up the heating time of your hot tub is by using a thermal blanket. A thermal blanket is designed to trap and retain heat, preventing it from escaping into the air.

When you’re not using your hot tub, simply place the thermal blanket over the water’s surface before closing its lid. Doing so will create an additional layer of insulation that helps maintain higher water temperatures while also reducing heat loss through evaporation, which can otherwise occur at a rapid rate during colder seasons or windy weather conditions.

Start With Hot Water From A Hose

One way to speed up the heating time of your hot tub is by starting with hot water from a hose. This method can help increase the initial temperature of the water, which means that the heater will have less work to do overall.

It’s important to note that this should only be done if it’s safe and feasible for you to do so – some hoses may not be made for use with hot water, so make sure you check before using one.

Invest In A More Powerful Heater

One way to speed up hot tub heating time is by investing in a more powerful heater. The size of the heater and its efficiency play a significant role in how fast the water heats up.

For those who frequently use their hot tubs or live in colder climates, upgrading to a higher wattage or gas-powered heater can reduce heating times by several hours. However, these heaters do come with higher costs and may require special electrical wiring or gas lines.


In conclusion, the heating time for a hot tub depends on various factors such as its size, starting water temperature, and heater power. While smaller hot tubs may heat up in 60-90 minutes, larger ones may take up to 6-8 hours.

To speed up the process, using a hot tub cover or thermal blanket can be helpful.

Remember that proper maintenance and operation of your hot tub is crucial to its efficiency and energy usage. Always refer to your hot tub manual for specific instructions and consult with professionals if you have any concerns about your equipment or chemistry.

Related Posts

How much is an inflatable hot tub?

How to drain inflatable hot tub?

Why is my inflatable hot tub not heating?

What can i put under my inflatable hot tub?

How much does a Hot Tub weigh?

Are Inflatable Hot Tubs worth it?

Visited 21 times, 1 visit(s) today
Last modified: August 18, 2023