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How Much Does a Hot Tub Cost Per Month to Run?

Hot tubs aren’t known for being inexpensive. But even after you pay a lot to buy and install your hot tub, there are the ongoing costs of chemicals and electricity. So how much does a hot tub cost per month?

The total costs to operate a hot tub should not exceed $50 per month. A standard 220v hot tub will add about $20-$30 per month to an electricity bill, and chemicals, water refills, and filters will average approximately $6.00 per month. 

In this article, I will share with you some of the things I picked up from owning 4 hot tubs over several years and how to get the most out of your buck.

We’ll look at ways to save money on chemicals, maintenance costs, and your monthly electric bill. Let’s dive into to.

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Is it cheaper to leave a hot tub on all the time?

A hot tub will be cheaper on electricity if it stays at a constant temperature. Lowering and raising cause the heater to work more often, resulting in a larger electricity bill. However, it may make sense to lower the temperature if on vacation for 3 or more weeks.

The biggest chunk of money goes into raising the temperature of the water in your hot tub from its standing temperature (the unheated temperature) to an enjoyable temperature of between 98 and 104°F.

So, if you’ve just filled your hot tub, the energy required to heat up the water is dependent on:

  • The temperature of the water in the tub: Upon filling your tub using a garden hose, the water may be anything from 50 to 80°F, depending on the time of year. So if we say on average 65°, you have to raise it 35° to get it up to a desirable 100°, and this requires a lot of energy.
  • The outside air temperature: This affects the rate of heat loss while the water is warming up. Cool air with a light breeze will chill the water’s surface, so it is a good idea to leave the lid on in these conditions, but don’t forget to keep checking the water level.
  • The amount of water to be heated: If you have a 400-gallon hot tub, it will take 25% longer to heat up the water than a 300-gallon tub, while your heater is working flat out to raise the temperature by 35°.
  • The size of your heater: A 2kW heater will heat up the water twice as fast as a 1kW heater.

All these factors affect the cost of raising the temperature by an average of 35°.

Once you’ve reached that temperature, things calm down a bit. Your heater is only working to keep the temperature at 100°. If it drops a couple of degrees, it takes a minimal amount of energy to raise it back up again.

So, to answer the question, yes, it does work out cheaper to leave your hot tub on all the time.

Does turning down the hot tub save money?

Turning down the hot tub and leaving it set to a lower temperature will save money as the heater will come on less frequently. However, turning it down in between soaking sessions and then back up again will result in more work for the heater to re-heat the water, ultimately costing more money.

If you’re not going to be using your hot tub for a while, it’s ok to turn the temperature down a little. After all, every drop in degrees will save you a little bit. But it won’t save a ton.

How much can you save?

Check out this recent article where I get into all the specifics, including the 1 key thing that will save you the most money. Just click that link to read it on my site.

If you’re using your hot tub in the middle of the summer and the air temperature is 100+°, you might want to turn the temperature down to say 95°. So long as you keep running at this temperature, you will save money.

It is the energy required to raise the temperature by large amounts that boost your electric bill.

In the cooler months, if you turn down the temperature to 95°, this will be too cold to enjoy a good soak, so you will end up spending more money to raise it to 100°, or more likely 104° if it’s so cold outside, every time you want to use it, and if this is 2 or 3 times a week, that adds up to quite a bit of cash.

How much does it cost to heat a hot tub in the winter?

The average cost of running a hot tub in winter will be 30-50% higher for a total monthly cost of $26 to $45 per month. It will be on the lower end in climates that are less cold and for hot tubs that are better insulated.

But all of the factors of that range are:

  • cost of electricity in your area
  • size of the hot tub, which includes the volume of water
  • rating of the pump in kW.
  • number of times you use it per week
  • winter climate where you are.

Energy costs are measured in cents/kWh, and that varies depending on your provider. They vary from around 13c to 18c, but you can find out by looking at your electric bill.

As a basic guide, to heat 100 gallons by 1℉ it takes around 0.25kWh. So, to raise the temperature of 400 gallons by 35° would use 35kWh. Even at 15 cents, that’s just over $5 to heat your water, less for smaller tubs.

The heater on a 110v hot tub is likely to be around 1kW, so it could take up to 15 hours to get to 100° from 75° in a 250-gallon tub. A 2kW heater would do it in half the time.

Inflatable hot tubs are more expensive to run because they are less well insulated.

But how expensive are they to operate, and do they even work when it’s cold in winter? You can read more about it in the recent article on my website.

Just click on the link to open it.

So, the cost in winter is higher because the water cools quicker when your hot tub is in use, and when it is not in use even the best-insulated tubs will lose more heat than in the summer.

What is the cheapest way to run a hot tub?

The least expensive way to operate a hot tub will be to set the temperature below 100 degrees Fahrenheit and use either economy mode or sleep mode, which causes the heater to only kick in during filtration cycles.

To make sure you get the best out of the heater, you must also regularly check the condition of the water and the filters.

Efficient running of your pump and heater requires regular maintenance to prevent a buildup of biofilm – the gunge that builds up from body lotions, deodorants, hair, and dead skin.

Most of this is filtered out, but some find their way into the pipes making the pump work harder and therefore use more electricity.

As well as electricity, you have to consider the cost of: 

  • water to fill a hot tub
  • replacing filters
  • chemicals to keep the water clean

Just looking at the amount of water needed to run a hot tub, you will have to change it 3 or 4 times a year, so if you have a 400-gallon tub, that’s between 1,200 and 1,600 gallons a year. That’s the equivalent of a small pool!

In many areas, the cost of water supplied includes the cost of treating it at the sewage plant once it’s used – they assume 100 gallons in = 100 gallons out. Well, you’re not going to pour your hot tub water down the drain, so why not try and negotiate this cost out of your water bill?

Some of the products needed to keep the water in balance may already be in your kitchen, such as baking soda to raise the alkalinity or white vinegar to lower it.

You don’t have to pay top dollar for your filters and chemicals. Shop around. 

If this is your first entry into the world of hot-tubbing, you should read this recent article here on my website before buying. There are 23 great tips on what to look out for, including 1 that will save you a ton.

Just click that link to see it on my site.

How often do you replace the hot tub filters?

Plan to replace a hot tub’s filters every 12-24 months. Use the lower end of that range if water chemistry and filter cleanings are not performed as often as they should.

Filters can be $20-60 to replace and many hot tubs use 2 or more.

So they are one of the pricier things to buy for your hot tub. Unfortunately, no 2 are alike and there are dozens, if not hundreds of models. So make sure you get the right one(s).

The filters keep the debris out of your water and equipment.

As such, it’s important to keep them clean. Dirty filters mean poor water circulation and that can put added strain on the pump and heater.

So maintain the chemicals in the water weekly.

Then give the filters a quick rinse at the kitchen sink with a sprayer every 3 weeks and then a deep chemical soak every 3 months.

For the deep chemical soak, I just use some of the Power Soak product on Amazon. I add it and the filters to a 5-gallon bucket and fill it with hot water for 1 hour.

Then rinse them off and put them back in.

If you do that, combined with changing the water every 3 months, there’s no reason you can’t get 24 months of life from your filters unless your hot tub sees extra heavy use on a regular basis.

Do hot tubs use a lot of electricity?

Hot tubs do not use a lot of electricity and typically only cost about $1.00 per day to operate and maintain. Lower-quality, poorly insulated hot tubs are costlier on electricity, and poor water balancing can shorten the lifespan of the filters and equipment.

So don’t just focus on your electric bill, but the hot tub as a whole.

Inflatable hot tubs use more electricity because the walls are made up of two skins of vinyl and around 18″ of air, and the covers—if you get one with your tub—are not usually very well insulated. You can improve on this by using an insulated groundsheet and getting a well-insulated cover that fully fits the tub.

Of course, the size of the heater is one of the biggest factors when it comes to electricity use and hot tubs. Smaller ones are (obviously) not as efficient as the bigger heaters when it comes to raising the temperature of the water.

See this recent article to learn more about the amount of electricity plug-n-play hot tubs use.

Plug and play ones are convenient in that you just need a nearby outlet and not an electrician. But they aren’t always the best option for long-term costs.

Just click that link to read it on my site.

How much does an inflatable hot tub cost per month?

Inflatable hot tubs generally cost about $50-60 per month depending on the set temperature of the water and the ambient air temperature.

Inflatable hot tubs cost more to operate than other types of hot tubs due to both a lack of insulation as well as being heated by a 110v heater rather than a 220v.

This also typically means the heater is a 1 kWh heater instead of a 4 kWh heater. Also with a 110v hot tub, the heater and the jets cannot work simultaneously which means the heater has to work harder to fully circulate the water through the heater.

This both adds to the cost as well as means it will take longer to heat the water up when filling or refilling.

How much does water temperature affect monthly electricity costs on a hot tub?

A hot tub set to 104° add at least $5.00 to your monthly electricity costs compared to setting it to 98°. But the total increase or decrease will also be affected by the following:

  • What the ambient air temperature is (costs more in winter)
  • How well the hot tub is insulated
  • How tight fighting the cover is

To reduce electricity usage, the best thing to do is to add extra insulation under the acrylic shell and behind removable side panels. But you can also use a floating thermal blanket that serves as a solar cover. This floats on the surface of the water just under the hot tub cover.

Just take it off (in about 10 seconds) when you are ready to soak.

My favorite thermal blanket on Amazon is under $50 bucks, can be cut to size, and is an Amazon’s Choice product with well over 100 near-perfect reviews.

Is an in-ground hot tub cheaper per month than a portable hot tub?

An in-ground hot tub can be cheaper than a portable hard-sided hot tub if a cover is used. However, many in-ground hot tub owners do not use a cover meaning that the hot water evaporates at a much higher rate.

In winter, especially, this can significantly increase your electricity costs.

That being said, since an inground hot tub is literally buried in the ground, it naturally is better insulated around the sides. So that combined with a  tight-fitting cover will generally be cheaper than above-ground portable hot tubs.

Final thoughts

I hope this gives you the information you need to decide on whether a hot tub is within your means.

If you are prepared to put the time into keeping the water clean, follow the advice on insulating your tub to the maximum, and letting it run all the time during the season, the overall cost is not that great.

If you need any more advice, just reach out to me – I’d be glad to help. And don’t forget to click on those links to read other associated articles here on my site.

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Jeff Campbell