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How Much Does it Cost to Heat a Hot Tub in the Winter?

By: Author Jeff Campbell

Posted on  - Last updated:

Categories Hot Tub Expenses, Hot Tub Winter Tips

Hot tubs aren’t known for adding a lot to your electric bill. But in winter, especially if you live somewhere that gets really cold, how much does it cost to heat a hot tub in the winter?

On average, to heat a hot tub during winter, expect an increase of $20 to $30 per month on the electricity bill over the normal bill. However, for poorly insulated tubs, plug-and-play tubs, or inflatable hot tubs, the cost could be as high as an additional $50 per month. 

In this article, we’ll explore whether it’s cheaper to keep a hot tub hot or turn it down each time you get out.

But we’ll also look at the ideal temperature setting and whether it’s good to put insulation under it. We’ll also check out whether newer hot tubs are more energy-efficient and best way to make your hot tub more energy efficient.

Let’s dive right in…

cost to heat in winter lg

Is it cheaper to keep a hot tub hot?

It is cheaper to leave a hot tub on all the time at the temperature preferred for soaking, as opposed to lowering after each use and then raising the temperature back up. It costs more to re-heat the water than it does to maintain it at a set temperature. 

The above may come across as counterintuitive, right?

Wouldn’t it make sense to only switch it on each time you would like to use it? No. The reality is that once the hot tub has reached the correct temperature, it requires little energy to keep it going.

This is why it makes sense to keep it hot and why it is more economical.

It’s incredibly helpful to make sure that your hot tub has a high-quality cover which helps in ensuring that the heat is trapped in.

Some of the other factors that affect the hot tub water temperature are how well insulated the tub is and the ambient temperature. If the tub is well insulated, heat is easily trapped in.

So, there’s relatively little energy required to keep it running.

If the ambient temperature is hot, there won’t be a need for a lot of energy. This keeps the average cost of heating the water lower.

The converse is also true: If the ambient temperature is cold, more energy would be required.

Haven’t bought a hot tub yet?

There are so many questions and things to know about hot tub ownership. Luckily, I have a recent article that covers the 23 things you must know before you buy, and it is based on a mix of my experience and a survey of my readers where I asked them their tips, regrets, and frustrations.

Just click the link to read it on my site.

What temperature should I keep my hot tub when not in use?

As a general rule, do not alter a hot tub’s temperature unless it will go unused for 3 or more weeks. In that case, set the temperature to 98° F (36.67° C), or lower, or switch the mode to economy mode. If the hot tub use will go more than a month of not being used, consider powering down and draining.

Hot tubs are designed to be left on all the time, except when you’re going to be away for more than two months. One can be easily forgiven for thinking that it makes sense to turn it on and off after each use.

The reality is that it uses more energy when it’s being reheated than what it consumes when it’s at its regular temperature. If you plan to be away for a month or two, you may want to lower the temperature by 5 degrees. But, the truth is that the energy usage cost savings is not much.

But what if you won’t use it for a while but don’t want to drain it?

I devoted a recent article to take a deep dive into this issue. I get into several money-saving tips that will have the hot tub still ready for use upon your return, but the impact on the electricity bill will be minimal.

Just click the link to read it on my site.

Should I put insulation under my hot tub?

Insulation can be added under a hot tub, although it is more ideal to do that at the time of installation. However, the most efficient way to insulate is to add foam wrap and/or panels inside the cabinet under the acrylic shell and insulated wrap around the PVC pipes.

So when buying a new one, try and factor in a good insulated base into the installation cost.

But if your hot tub sits on a wood deck like mine, you are losing a lot of heat. A wood deck has slats that allow both heat and sound to pass through, amplify the tub’s noise, and increase inefficiency.

So, if it is to be placed on a wooden deck, you may want to put it on spa pads like this one on Amazon.

But, it is better to insulate inside the cabinet because not much heat escapes from under the hot tub. It stands to reason that it’s better to focus on where you’d get the most value for your money. A concrete slab, however, will be the better choice if you haven’t already added your hot tub.

Say you’re considering plug-and-play hot tubs. Are they expensive to run?

Luckily, that’s what I explored in a recent article of mine where I said that they are not expensive to run but might the ongoing expense might be costlier than portable or in-ground models.

They operate at low voltage, and as the name implies, they remove the need for an electrician as you can connect them directly to a GCFI-protected home outlet.

Just click the link to read it on my site.

Will a new hot tub be more energy efficient?

As a general rule, the newer and more expensive a hot tub is, the more energy-efficient it will be. Newer models tend to come with better insulation, controls, and pumps. But an inexpensive newer model will likely still be poorly insulated.

There’s the temptation to buy cheaper older models or fix up a used one.

But, these are naturally based on older technology, and you’d be missing out on some innovations that come with newer models. You will end up spending more on hot tub energy costs even though the actual price of the hot tub may be inexpensive.

Having said that, another factor that’s even more important than the age of the hot tub is the manufacturer.

Some models haven’t changed much in the last 10 years. If you’ve got to choose between a model like that and some new model by an average manufacturer, an older model would still be the way to go.

In other words, a high-end, reputable brand, even if it’s not new, can be more energy efficient.

What if you’re planning to buy an inflatable hot tub? Are they expensive to operate?

As I showed in a recent article of mine, they are quite expensive to maintain. On average, expect to spend about $50 each month on electricity bills. Of course, the actual cost depends on your set temperature and the climate. Amongst other things, I also explained why they are expensive to run.

Just click the link to read it on my site.

How can I make my hot tub more energy efficient?

Make a hot tub more energy efficient by adding insulation under the shell, wrapping PVC pipes, buying a tighter fitting cover, and keeping the temperature set consistently at 98° F (36.67° C). Additionally, set the filter cycles to occur during off-peak hours when your electricity rate is lower.

Let’s check out some of these steps.

Buy a Higher Quality Cover

A good hot tub cover is one of the best ways to make your hot tub more efficient as it would trap the heat in the tub and also help prevent water loss. Consequently, the pumps and the heater won’t have to work as hard.

You need a good cover in good condition that has no tears, cracks, or any damage. And it needs to fit tightly around the rim of the hot tub to prevent heat from escaping.

A high-quality cover has hinges that leave room for heat loss. It should be made of quality material and should fit perfectly around your hot tub.

Lower the Thermostat

The hotter the temperature of the hot tub, the more energy it takes to maintain that temp.

I like mine at 98° F (36.67° C), but even 100° F will save you money over setting it at 104° F.

So, you could experiment with reducing the temperature gradually, perhaps getting started with half a degree, then 1 degree, a bit more…and keeping a record of how the changes impact energy cost.

Keep the Hot Tub on

You’d think you could lower your running cost by turning the hot tub on and off regularly.

The counterintuitive truth is that you would most likely save running costs by keeping it on. It consumes a lot of energy each time it’s getting started.

So, it’s better to have it on all the time at the temperature you like to soak at.

Add More Insulation

You could add more insulation into the hot tub’s cabinet.

This would help trap in more heat and help you save costs in the long run. It’s better to have a professional do this so that the airflow isn’t too restricted, but it’s also not hard to add spray foam insulation yourself around the shell and the jets and then wrap PVC pipes with insulated tubing.

What are the best ways to lower a hot tub’s energy bill in the winter months?

Hot tub costs are a factor of the following:

  • What temperature you have the water set to
  • How well insulated the hot tub is
  • How cold the outdoor temperature is where you live
  • How powerful a heater your hot tub has

A 1 kW heater, for example, which is more common on plug-and-play and inflatable hot tubs, will have to work a lot harder than a 4 kWh (stands for kilowatt hour) heater will (most common for normal 220v portable hot tubs).

220v hot tubs are the most energy-efficient hot tub types due, in part, to the larger kW rating.

And generally speaking, the less you paid for that new hot tub, the more poorly it is likely to have been insulated. And less insulation means more heat will escape from the underside of the acrylic shell.

And it should go without saying that the same hot tub in Chicago in winter will cost a lot more to heat than it will in Texas where I live. I can usually count the number of days where it goes below freezing on one or maybe 2 hands.

But in the midwest, that can be daily for months in wintertime.

Do base pans help keep hot tub heating costs down?

A base pan is something your hot tub sits on. And depending on what it is sitting on, it can impact the operating costs of a hot tub.

That being said, it’s not nearly as big a factor as the other issues I mentioned above.

And if you have already had your hot tub installed, emptying it, disconnecting the electricity, and moving it or lifting it to place a base under it could be very challenging, costly, and time-consuming.

And frankly, that won’t be worth the hassle as it won’t save much electricity.

You would be better off adding additional insulation around the shell and behind the removable panels of your hot tub. 

That is actually fairly easy.

Luckily, I showed you exactly how I did it to my hot tub in this recent article. Just click that link to see the exact step-by-step process I followed, right here on my site.

Do hot tub filters affect the cost of operating a hot tub?

Generally speaking no, unless they are exceptionally dirty.

A dirty or clogged filter means water will flow more slowly through the pump and heater. This can put additional strain on the pump which can add slightly to the overall electricity cost.

More importantly, though, it will add unnecessary wear and tear on the pump.

And if the heater tube doesn’t get enough water flowing through it, it can actually cause the high limit switch to trip. That is a safety feature designed to prevent overheating.

Conclusion

In this article, we explored whether it’s cheaper to keep a hot tub hot all the time.

But we also looked at the ideal temperature setting and whether it’s good to put insulation under it.  We also checked out whether newer hot tubs are more energy-efficient, and we wrapped up by looking at ways to make your hot tub more energy efficient.

The good news is it’s not that hard to keep your monthly costs relatively low, even in winter. Of course, the local climate and energy-efficiency of your hot tub will impact that.

But in most cases, you shouldn’t see a huge spike in your bill.

Photo which requires attribution:

Hot Tub 01 by Tom Hilton is licensed under CC2.0 and was cropped, edited, and had a text overlay added.

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Jeff Campbell
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