How To Heat Up A Hot Tub Quickly

how to heat up a hot tub

If you’ve owned your hot tub for a while, you probably already know how long your particular model takes to heat up. And if you’re a new owner, you might just be wondering how long you have to wait before you can comfortably get in.

Every spa is a little different and we’ll cover that in a moment. But no matter what type you happen to have, there are ways to heat the water up a little faster.

How long does it take to heat a hot tub?

There isn’t really one straight-forward answer to this question because it depends on a few different factors. The outside temperature, water temperature, size of the tub, and power of your heater all play a part in how quickly you can heat up your hot tub.

But we can give you a pretty standard answer: it takes anywhere from 3 to 8 hours to heat your hot tub water to around 100°. On average, most hot tub owners say 4 hours is pretty common.

In other words, they heat up at a speed of about 3-6° per hour. This is assuming your heater is working well and it’s a fairly sunny day.

However, there are some things you can do to speed up the process. 

How to Heat Up a Hot Tub Fast

A hot tub will always heat up faster with jets. This is because it disburses the heated water throughout the tub more efficiently and breaks up any cold pockets hanging around in the pipes.

And you can also put a cover over the hot tub with the heater and jets going to trap the heat inside. 

Additionally, keep a cover on your hot tub any time it’s not in use. This will keep some of the heat in from the last time you used it.

If you still have trouble heating up your hot tub very quickly, the problem could be your heater. If you’ve had your spa for a while, it’s possible it’s going out or just not working as well.

In this case, it might be time to replace it.

But being well-used is not the only reason your heater might need replacing. It’s also possible you just have a weaker model and you could use a more powerful one.

If you think this might be the case, you can check with your hot tub manufacturer or a local retailer to find out if there are better models available to you.

A word of caution here. Many hot tub owners are tempted to pour in hot water themselves, getting the temp up faster. 

While this sounds good in theory, you run the risk of damaging the shell if your water is too hot. 

Hot tubs are made to withstand water temps of up to 104°, so if you can test your water to make sure it’s not hotter than that, it’s probably OK. But keep in mind that boiling water is over 200°, which can strip away some of the coating on the shell.

How To Improve Hot Tub Energy Efficiency

The thing about hot tubs is that they can jack with your electric bill, especially if you use them all the time. On average, you’ll probably see a spike of about $50 a month. 

While most people probably don’t consider this to be too terrible, it still makes a difference. And there are ways you can keep that cost even lower. 

  1. Use a cover

A hot tub cover makes a huge difference in how quickly you can heat up your tub, therefore keeping energy consumption down. It also keeps the water clean so maintenance is a lot less of a hassle.

  1. Keep your hot tub in a shielded area

Nothing cools off your water like cold air or snow. It’s best to keep it in a protected area or put a wind block up around it.

This can be a fence, trees, or panels. Whatever provides a little protection from the elements.

  1. Lower the thermostat

Turning the heat down just a few degrees will go a long way toward lowering that electric bill. And the truth is you probably won’t even notice.

This is especially helpful when you’ll be away for a while. At these times, you can lower it even more and then raise it back up when you get home. 

Just be sure to keep it well above freezing in winter months! 50° is usually sufficient.

  1. Know when to heat your water

Did you know that your electric company charges you more for usage during certain parts of the day? 

Yep, when demand is highest, you pay the most. For most places in the US, these peak hours are 10 AM – 8 PM during the summer and 7 AM to 11 AM/5 AM – 9PM in the summer.

Knowing what these peak hours are and heating at different times could save you a little on your bill.

Heating a Hot Tub FAQs

Do the jets have to be on to heat a hot tub?

They don’t have to but it sure speeds up the process and heats more efficiently if they are. Jets help distribute the heat throughout the spa as well as break up any cold bubbles of air stuck in the pipes.

Should I leave my hot tub on all the time?

Yes! This is actually how they’re designed to work best. This keeps the water circulating, cutting down on bacteria and algae outbreaks. And it also keeps the water fairly warm so that it doesn’t take as long to heat it every time you get in. 

It is important to note that you can turn down the thermostat when you’re not going to be using it for a while or will be out of town. And you’ll also have to turn it completely off when you’re draining it for cleaning or refilling.

Why is my hot tub not heating up?

There could be a few reasons for this. The most common is a dirty filter. 

Hot tub filters need to be replaced about once a year, but in between, they sometimes need cleaning. If your heater seems to be lagging, try this first. Take out the filter and rinse it off well.

If this isn’t it, you might have a blown fuse or tripped circuit. Check your circuit breaker or GFCI test button to make sure you’re getting electricity.

If everything else seems to be in working order, you might have a damaged unit. The problem could be the temperature sensor, heating element, or the entire unit itself. 

You can inspect the heater yourself and look for damaged wires or anything that looks out of the ordinary. But you will probably need a professional to check it out and fix it.

How hot should my hot tub water be?

Hot tubs are only made to heat water up to a maximum of 104°F, but many people find this a little too hot. 100° is a much more common temp for hot tubs. 

Children, older people, and pregnant women, however, should never be in water that hot. Usually 95° is the max for these folks and they shouldn’t stay in more than 10 minutes at a time.


Your hot tub is designed to be heated for maximum enjoyment and comfort. So in most cases, this should be an automatic function.

However, sometimes you just want to heat it up and get in as soon as possible and as you can see, there are multiple ways to do this.

But in all cases, please remember to consider your bathers. Keep your water at the appropriate temps to be safe for everyone!

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