How Long Does a Hot Tub Take to Heat Up?

Your hot tub is in the backyard. It’s ready to go. You’ve stretched out the garden hose and turned the tap on to fill it up. You watch the water hit the hot tub and you think, “wait a minute, this water is cold! How long is it going to take to heat up my hot tub?”

You’re not the first and you won’t be the last to wonder about this question. We are asked about this frequently, especially from new buyers or people considering buying a hot tub. Most of them are excited about using their hot tub for the first time and want to know how fast they can get into it. 

Here’s the best answer we can give you: A hot tub’s temperature will increase between 5-10F degrees per hour. For most hot tubs, that means it will take between 3-8 hours to heat it up. 

Of course, many factors affect how fast your hot tub warms up, such as the size of the hot tub, the outside temperature and other elements. That’s why we give a range. 

We know this from years of filling up hot tubs in our showrooms, but we’re happy to show you the math behind it.

• The water coming out of your cold tap will generally be about 60F. 
• After three hours at 10F an hour, that will put your hot tub at 90F and at four hours it should be around 100F (hot tubs are capped at 104F). So you will have reached your desired temperature. 

In this article, we will also go over:

1. Factors in your hot tub temperature: outdoor temperature, insulation etc.
2. Does a hot tub heat faster with jets on: Tips and tricks
3. Is it okay to fill a tub with hot water? 
4. How important is your cover in keeping your hot tub water warm? 
5. Should I keep my hot tub temperature at one temperature? 

There are also a few tips and tricks we can give you to help with this process. Hopefully, by the end of this article, you know everything you need to keep your hot tub water as warm as you like it.

 

 

What Are the Factors That Determine how Long it Takes for Your Hot Tub to Heat up? 

There are several factors that come into play, which include:

1. Ambient temperature: On a warmer day, your hot tub will heat up more quickly than on a colder one
2. The temperature of the water in your hose (more on this later) 
3. The quality of insulation in your hot tub: The better it is insulated, the more it will be capable of holding in heat
4. The condition of your hot tub. The older your hot tub gets, the more likely it is your heater element won’t crank out as much as it used to. 

How Can I Make My Hot Tub Heat up Faster? 

There are two tricks we can suggest that can speed up the process:

1. Keep your lid on when you fill your hot tub with colder water. 
2. Keep your jets on when filling your hot tub with water. Circulating the warmer water will help warm the rest of your water.

Can I Just Fill My Hot Tub With Hot Water? 

This seems like it should be easy, but using hot water has been known to create the odd problem. So it is generally better to put in water around 50F (which is typical from a hose or cold water tap) and then raise the temperature of the water along with the hot tub itself at the same time. 

But should you want to use hot water, here’s our best advice: 

1. The hot water is not hotter than the hot tub can handle, as in it won’t damage your hot tub as you fill it. Some hot tubs do not allow this at all – it’s best to check your manual or talk to your local retailer to find out if your hot tub can take hot water. 
2. The hose you’re using is rated to handle hot water. If it’s not, you could end up with a bunch of melted plastic put into the hot tub.  
3. You’re using a tankless water heater. If you’re not using a tankless water heater, you’re just going to drain your hot water in your house, because your hot tub holds much more water than your hot water tank. 

How to Keep Your Hot Water Hot in Your Hot Tub  

There are a few ways that you can help improve the efficiency of your hot tub which will not only speed up how fast the water will heat up but also reduce costs on your utility bill. 

• First and foremost, make sure that you have a quality, insulated cover that will trap heat inside the hot tub. If you need to purchase a cover, look for a lockable one with tapered edges that will keep as much heat inside as possible. If your existing cover has a hole, cracks or damage - heat is escaping which is costing you time and money.
• Something that most hot tub owners rarely think of when considering how long it will take to heat their hot tub is their landscaping. There are ways that you can help reduce the pull of heat from your hot tub's water, including surrounding your tub with trees and shrubs or using a windshield or enclosure to prevent cooler air from reaching the water.

 

Should I Keep My Hot Water at One Set Temperature? 

Should you always leave your hot tub running? Or should you turn it off and only heat the water when you are planning on using it?  

In general, our advice is to leave it running. Any savings will be minimal and this way you are able to use your hot tub any time you want. And in general, the cost of keeping your hot tub at a set temperature typically costs less than if you’re warming it and cooling it and warming it again. 

• For anyone who wants to use their hot tub in the winter, it is best to leave your hot tub running to prevent freezing or damage. 
• If you are located in a warmer environment and only occasionally use your hot tub, it probably makes more sense to turn it off and only heat the water when you want to use it. Although this does take a bit of planning, it could save you some money on your overall energy costs.

How Long Does it Take to Warm up a Hot Tub? 

Our answer for most hot tubs is that it takes about 3-8 hours. We get asked this a lot, and we have figured this out by the sheer number of hot tubs we have set up in our stores and put on display over the 40 years we have been in business.

Having a hot tub reach the heat you want is crucial for any hot tub owner. And we hope this article has answered your questions as fully as possible. But we also know we might have missed something specific to your situation. If we have, then please reach out to the local retailer nearest you.