How Long Does It Take to Heat a Hot Tub? (& how to speed it up!)

New hot tub owners or those who have just changed the water often have 1 common question: How long does it take to heat a hot tub?

Here’s what I’ve found in owning 4 of them:

It can take anywhere from 3 to 8 hours for hot tubs to reach the desired temperature. Factors include the capacity of the tub, ambient air temperature, and the temperature of the water from the hose. On average, most hot tubs will take about 4 hours to reach 100 degrees.

But there’s a lot more to know about heating up a hot tub, including how to speed that up and the 1 thing you should never do that could damage your tub.

So let’s keep going!

The rest of this article will discuss some crucial questions related to heating your hot tub:

  • How long does it take for a hot tub to warm up?
  • Does a hot tub heat faster with jets on?
  • How can you heat a hot tub faster?
  • Can you fill a hot tub with hot water?

Of course, in a lot of cases, you’ll be wondering this after draining your hot tub water.

So aside from heating the new water back up, a lot of people wonder how long it takes to fill a hot tub back up again!

I cover that too in a recent article. I break down not only how long it takes, but ways to speed that up. Then, I even cover 1 cool trick that will let you drain a tub in as little as 15 minutes!

Just click the link to see it on my site.

Ready to Spend Less Time On Maintenance and More Time Enjoying Your Hot Tub?

Let’s face it. Balancing the water, cleaning filters, dealing with rashes, and trying to figure out which chemicals to buy and add can make you feel more like a chemist than someone who just wants to relax after a long hard day!

That’s exactly why The Hot Tub Handbook and Video Course is so valuable!

This is from Matt over at Swim University and he developed it for people looking to save money, time, and frustration. His tips on chemicals can save you $100/year just by making sure you buy only what you need.

So if you’re ready to stop being confused or frustrated with your hot tub and start spending more time in it, check out The Hot Tub Handbook and Video Course.

Just click that link to learn more on their website.

How Long Does It Take for a Hot Tub to Warm Up?

Soaking in a nice, warm hot tub is second to nothing after you’ve worked a long day. However, you need to ensure the water is hot before you jump in.

There are 3 instances in which you’ll need to heat a hot tub at home:

  1. When you’ve freshly filled the tub after purchasing or draining the spa
  2. If you lower the temp in between uses, you’ll need to reheat it before you get in
  3. If you power down and winterize it during the cold months

The current temperature of the water in the hot tub will impact how long it takes to heat.

On a warm sunny day, you might notice that the water sits around 80 degrees without internal heating. This means that you’ll only have to warm it up for a couple of hours – maybe three at most.

Colder water that’s 60 to 70 degrees could take a bit longer. Don’t worry, though, as it’ll only add an hour or so to the process.

Think summer is too hot to use your hot tub? Think again!

While the water in your tub can easily get to unsafe levels in summer in extra hot locations, in a recent article, I cover a few simple but cool tricks to lower the temp in your hot tub.

That way you can use it, even in Texas (where I live) in August! Just click that link to read it on my site.

It’s a good idea to allow about 5 hours to heat cold spa water. If you have a lid, keep it closed for quicker heating.

The size of the heater and the tub also have a large impact on the water temperature.

Think about boiling water on the stove; it takes longer to heat when you use a big 2-gallon pot than when you use a tiny 2-quart pot, right? The same principle is in play here.

Big tubs require more time than small tubs.

Does a Hot Tub Heat Faster with Jets On?

Yes, is the short answer.

Jets are a fantastic addition to any spa. They allow the user to relax in complete comfort and receive a gentle massage.

However, there’s also a little-known additional purpose for these convenient jets; they’ll help you heat your hot tub quicker.

Turning on your spa jets will begin to circulate the water, moving it around and dispersing the heat evenly.

Without using jets, there tend to be pockets of cold water that hang out in the pipes inside of the hot tub. The circulation from the jets flushes the pockets, mixing the cold water with the heated water.

This process can make it so that the water heats up around three to six degrees per hour!

The only precaution that you should think about is to avoid turning on the jets or heater until the tub is full.

Some owners think it’s a good idea to start heating it as soon as the water hits the first jet, but that’s far from the truth. You can’t run water through the jets until they’re all submerged, as doing so might damage the whole system.

If your hot tub doesn’t have jets, you can try to circulate it with your hands or a pool noodle. While it doesn’t work as well as a set of jets, it can still help to move the water and heat the tub a bit faster.

Keep in mind that a lid will always heat your water faster than manually stirring it will. Therefore, you should cover your tub if you can.

How Can I Heat My Hot Tub Faster?

There are three methods you can use to heat your spa more quickly:

  • Place a cover on the hot tub. Without a lid, the exposure to the cold outside air will make it harder for your tub to heat up. Any temperature lower than your desired water temperature is working against the process. If you don’t have a lid, try a tarp!
  • Use a more powerful heater. The three main heater types used in the pool and spa industry are 150k BTU, 250k BTU, and 400k BTU. While many people see a 400k BTU heater as a bit overkill for a spa, you can still get a 250k BTU heater if you want to heat it faster. A small spa with a 250k BTU heater can cut the heating time down by an hour or more.
  • Turn on every jet and water feature in the hot tub. Doing this will improve circulation and heat your water more evenly. Some hot tubs only have a few jets, while others have built-in fountains on the bottom as well as massaging jets lining every seat. Once there is enough water to cover them, turn everything on to heat the hot tub as quickly as possible.

Another common question hot tub owners have is how hot SHOULD the water be?

After all, we hear 104, but that sounds pretty hot! And for those of us with young kids, is that too hot?

Luckily, I take all the mystery out of that in a recent article.

I break down not only the maximum safe temperature. But I also list out maximum safe soaking times by temperature. That way, no matter how hot you like it, you’ll know how long you can safely sit in it.

Just click that link to see it on my site.

Can You Fill a Hot Tub with Hot Water?

After sitting around and waiting for a few hours while the hot tub warms up, it might be tempting to consider throwing in hot water the next time.

While using preheated water seems like a good plan, you shouldn’t do it, as it can damage your spa permanently.

Never put water in that’s higher than 104 degrees, which is the highest setting on most hot tubs.

When you throw in boiling water or even water around 110+ degrees, it has the potential to sear the lining of your spa.

Your hot tub isn’t designed for scalding temperatures, which means that the materials might begin to melt or give way. Acrylic spas tend to be the first to show signs that it’s far too warm.

If you really want to add hot water to the tub, you should first fill it up with regular water through the hose to the halfway point.

This will help to disperse the hot water instead of letting it sit concentrated on the surface of the tub. Even then, the heated water might be a problem if it goes directly into the pump and filter.

Hot water that’s higher than the spa’s temperature settings can also ruin the pump, jets, filter, lining, and materials.

It might speed up the heating process slightly, but it’s not worth the risk involved.

Simply following the three recommended steps above will be your best bet to ensure a safe, speedy heating time.

Confused about how often to change the water in your hot tub?

You’re not alone! In a recent article, I break down all you need to know about how long you can let your water go before changing it.

I also cover how to change it quickly and easily and the 1 sure way to tell if it’s not safe to soak in.

So just click that link to see it on my site.

Did I cover all you wanted to know about heating up a hot tub and how long that takes?

In this article, we took a look at the world of hot tubs and how long they take to heat up.

We explored why you might need to heat them up. But we also looked at ways to speed that up. And we covered the 1 thing you should never do in trying to speed up the heating, as it could damage the tub.

Here are the main points you should take away from this post:

  • It can take anywhere from three to eight hours to heat a hot tub. The time it takes depends on the size of the tub and heater, the temperature of the water and air, and whether you use a cover or jets.
  • A hot tub will heat faster if the jets are on. The jets circulate the water and ensure no cold pockets remain trapped in the pipes.
  • You can heat a hot tub faster by turning on the jets, placing a cover over the tub, and using a more powerful heater. These are the easiest and most effective ways to increase your tub’s heating speed.
  • It would be best if you didn’t fill a tub with hot water. While it might make the process a bit faster, hot water can permanently damage the tub.

Looking to get a quote on a new hot tub?

Save time and receive multiple quotes for hot tubs from all the best-known brands!

I have arranged with to provide free quotes from all the best hot tub manufacturers – with no obligation to buy. Simply complete BuyerZone’s request form below.

Are hot tub chemicals confusing you?

Hot tub chemicals can definitely be confusing. It’s hard to know how much you should add. Or for that matter, which ones should you buy or are even necessary?

Luckily, I take ALL the confusion out of it in a recent article.

I get into exactly what chemicals you need but also the ones you don’t need that are a waste of money.

But I also look at which chemicals are best for sensitive skin and how to avoid hot tub rash.

Just click the link to read that on my site.


Jeff Campbell

Jeff Campbell is a husband, father, martial artist, budget-master, Disney-addict, musician, hot tub lover, and recovering foodie having spent over 2 decades as a leader for Whole Foods Market.

Top Related Posts