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How to Heat a Hot Tub Without a Heater

Looking for how to heat a hot tub without a heater?. Well, heating a hot tub can take hours, and not to talk of the big electricity you will pay at the end of the month if your hot tub is on constantly.

Despite knowing the benefits of using a hot tub, but the costs can keep you away from using it.  Some people have asked how to heat a hot tub without using a heater to do so for reasons known to them.

Maybe they want to cut down energy costs or reduce the time spend on heating the hot tub.

how to heat a hot tub without a heater

It could also be your hot tub heater is faulty and you haven’t had the time to fix it yet want to enjoy a hot soak. A hot tub heater is one of the major components of the hot tub and without it, your tub won’t be able to heat the water.

This article, will explore some of the ways you can have hot water, though some are risky, you still have some options.

But first of all, let’s look at how long a hot tub generally takes to heat up if working properly.

How long Does a Hot Tub Take to Heat Up

The time it takes to heat a hot tub depends on the model you are using and how powerful the heater is. But typically, hot tubs heat between 3 to 6 degrees every hour. This will depend on a number of factors.

Generally, heating a hot tub shouldn’t take longer than 8 hours to reach its temperature, if it does, then you may be having problems with insulation, a lower-powered heater, a defective thermostat, or a defective heater.

At its lower end, these can add additional 5 hours to the heating time.  It can even take as long as a day to heat up due to many issues but the typical is between 3 and 8 hours.

Here are hosts of reasons why your hot tub may be taking a long time to heat up.

  • Colder garden hose temperature
  • Your hot tub jets and other features are not turn on
  • Your hot tub cover is off or is partially damaged

In colder weather, the water is generally cold and may take longer to heat up,  if you want the tub to heat quicker, it is also best to turn on the jets to improve proper mixing of the hot and cold water.

When the cover of your hot tub is off or is partially damaged, the heat energy will be evaporating through the surface of the water. Therefore, if you want the hot tub to heat up quicker, then make sure the jets are and the tub cover are on.

But if the hot tub heater stops working properly, use these methods to heat your tub up comfortably.

Ways to Heat Hot Tub Without a Heater

Here are a few tips you can use, but NB: you do it at your own risk.

First of all, though the heater is the quickest way to effectively heat your hot tub, it isn’t the only way.

1). Let It Warm Up in the Sun

Letting your hot tub warm up in the sun during the sunny days is one way to naturally heat up the tub but this could take several hours if the hot tub is not working efficiently.

But this will only work if it’s summer. But what happens if it’s winter or on any cold day the sun is not high?. Well, there are others ways you can try. Some are risky.

Add hot water to the hot tub – This is generally not recommended because though it may work, but there are a lot of issues that you may encounter like damaging the hot tub shell with extremely hot water, filling your hot tub with water that may contain softener that can cause corrosion thereby, invalidating your warranty.

Hot tubs can heat up to 104 degrees celsius, but water from your home heater can go as high as 140 degrees. Putting water with a temperature higher than the maximum hot tub temperature will prone your hot tub shell to cracking and damaging.

But you can minimize this by adding an additional hose to combine cold and hot water simultaneously and if possible get a thermometer to keep track of the temperature.

To add the hot water, start by quarter filling the hot tub with cold water and then add the hot water. Keep in mind to check the temperature at internals to prevent it from exceeding the standard hot tub temperature.

This will ensure you are in the safe zone. You can balance the cold water with hot water to a certain temperature below the hot tub standard temperature. At that point, you can switch on the hot tub heater to bring the temperature up to the standard temperature.

But like I mentioned earlier, you do this at your own risk. Here is an in-depth article on adding boiling water to your hot tub.

2). Connect a Rinnai Tankless/Instantaneous LPG Hot Water Heater and 9KG BBQ Gas Cylinder

Here is another trick a hot tub owner shared on a forum that worked out for him without using any power apart from the pump power. He said it heated his tub much quicker too.

I haven’t personally tried this though.

He bought a Rinnai tankless/instantaneous LPG hot water heater and connected it to a 9KG BBQ gas cylinder and run the garden hose from the pressure side of the pump into the inlet, and out of the heater into the suction side of the pump.

According to him, the water heats up within 1 hour to over 100 degrees. He then uses a Rinnai electronic controller which keeps the temperature at  42 degrees Celcius. Read more on this tread here.

3). Use Natural Gas Header Pool and Spa Heater

This is a huge investment but I am sure it’s going to be cost-effective in the long run. This high-efficiency C-Fin heat exchanger is designed to lower operating costs and provide greater savings.

These natural gas heat pools and spa heaters help keep your pool and spa hot at a lower cost. They offer exceptional protection against corrosion and premature failure caused by unbalanced water chemistry, ensuring you get season after season of premium heating performance.

They have leading hydraulic performance coupled with lightning-fast speed-to-heat capability—so you spend less time waiting, and more time swimming. If you have the cash to invest then you can check out this Hayward Universal 250,000 BTU Natural Gas Pool and Spa Heater.

Other Uses of  a Hot Tub

The best thing about a hot tub is that it does not have to be hot to use. Sure, the warm water makes for a great, relaxing soak that can do wonders for aching joints and muscles.

But just in case you don’t want to explore any of the above heating options, you can just use the tub as a pool.

One of the most common ways to use a hot tub is to treat it like a pool. This works in any season because, on hot days, you can use it to cool down and in winter you can also use it for an ice bath.

Another way to use your hot tub is to turn it into an exercise tool. You can turn your body around in ways that will keep you fit. The movement of your body will help in toning and shaping it.

Final Thoughts on How to Heat a Hot Tub Without a Heater

There are limited ways to heat a hot tub without a heater. This is because these hot tubs are designed to heat with their in-built electric heater. If for some reason, you wish to heat the tub without the heater, then you may have to invest in some of the tricks above but they also have their risks.

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