Can a Hot Tub Be Installed Indoors?

Written by Jeff Campbell in Installation

hot tub install indoor lg

I know most people like hot tubs because of the outdoor life they offer, but if it came down to it, can a hot tub be installed indoors?

As a general rule, a hot tub can be installed indoors. However, most hot tubs will not fit through a standard doorway and may require cutting a section of a wall to maneuver it. But proper ventilation, humidity control, and drainage are also crucial considerations.

But how do you vent a room?

Or control humidity, for that matter? And where do you drain it if you aren’t building the room from scratch? Or does it work to just stick it in a garage or use an inflatable hot tub?

We’ll answer all of those questions and more.

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What do you put under an indoor hot tub?

The beauty of an indoor hot tub is that you can place them on just about anything. You don’t need to worry about insulation, which is a factor for outdoor hot tubs.

However, the floor in your house was probably not designed to take a hot tub, so it’s not a case of what you put under it but what it sits on.

The weight of your hot tub is far more critical inside your home than it is outside. But how much do they weigh?

Just read this recent article to see a quick and easy way to calculate yours in minutes. And yes, I cover empty, with water, and with water and people.

Just click that link to read it on my site.

An average 6-person hot tub full of water and people can weigh as much as 4,000 pounds.

On a solid concrete floor, this won’t be a problem, but wood floors, and especially houses built on pier and beam foundations, aren’t designed for this kind of weight, so you will have to look at strengthening it.

This is not a straightforward matter, and I recommend you get a professional to look at this on your behalf.

Having established that the floor is strong enough to take the weight, you next need to look at the floor covering. This must be a material that can resist moisture and not create a slip hazard.

Things to avoid are:

  • Wood
  • Laminate flooring
  • Carpet

Ideal floor materials include:

  • Stained concrete
  • Stone pavers
  • Ceramic tiles
  • Vinyl flooring (sheet or tiles)

The final choice is down to you.

As I said earlier, bringing your hot tub indoors provides a great opportunity to create a spa experience second to none, especially if there is a sunroom you can use or other space you can open up to the outside world while remaining in your home.

How do you ventilate a room for a hot tub?

A nearby window and ventilation fan is crucial in an indoor room with a hot tub unless the room is a screened-in porch and naturally well ventilated.

As we all know, hot tubs create an enormous amount of steam water vapor, usually laden with the chemicals from the sanitization process. In the open, this doesn’t present a problem, but in your home, it can lead to major issues.

In most rooms in your home, you will have windows, but even leaving these fully open will not get rid of the steam generated by your hot tub. Plus, who wants to do that when it’s 30° or 100° outside?

Small portable fans do little to help either.

The average 90″ x 90″ hot tub will lose around 8,000 cubic inches of water in a week. That’s about 35 gallons. Imagine 5 gallons of water vapor swishing around the room every day!

Okay, I get that you won’t be using your hot tub every day, and when not in use, you will keep the cover on, but you get the idea.

So, for your hot tub room, you need something much bigger.

The other consideration is the size of your hot tub room. Obviously, in a smaller space, you will get a greater concentration of water vapor, but in some ways, that’s easier to handle.

Larger rooms have more space for the water vapor to hide and cause damage to the structure and finishes.

The perfect solution is the Genesis Twin Fan High-Velocity Reversible AirFlow from Amazon. You can find the latest prices and availability on Amazon by clicking the link.

Sized at 24″ x 12″ x 4″ wide, the Genesis twin fan sits neatly into the window opening, just like an AC window unit. The expandable side panels provide an additional 6.5″ of cover for each side for larger window openings.

It has a fully adjustable thermostat with a range from 60 to 80 degrees and 3 speed settings to make sure you’re getting rid of all that steam.

The great thing about this unit is the twin 9″ fan heads, each with its own copper motor, essential in the harsh environment of a spa room.

One final feature worth mentioning is the reversible blades that allow the unit to operate for intake or exhaust at the press of a button. But if it were me, I’d leave it on all the time as the hot tub will still be releasing some steam even when the cover is on.

How do you control humidity in a hot tub room?

Use a dehumidifier to control the humidity from the release of the warm water vapors from a hot tub.

The other important thing to consider when installing a hot tub indoors is humidity. While it’s essential to get rid of all that steam, you also need to maintain good humidity levels for your comfort.

Dehumidifiers are designed to absorb moisture from the air near the hot tub. They use heat to draw in the moisture through a compressor, which runs into a tank for manual emptying when full.

There are lots of these around, but one I like, because of the great reviews, is the hOmeLabs Energy Star Dehumidifier from Amazon. (Home Technologies, LLC is the trading name). Check out the latest price and availability here on Amazon by clicking on the link.

Designed for use in rooms of varying sizes – 1,500, 3,000, 3,500, 4,000, and 4,500 sq ft. – you are sure to get one that suits your space. The larger models have a pump to improve efficiency.

The hOmeLabs Energy Star Dehumidifier can remove between 22 and 50 pints of water a day, and being Energy Star certified, it can do this without racking up a huge energy bill.

This portable dehumidifier features a turbo mode to increase the fan speed from 118 cu. ft. per minute to 135 cu. ft. per minute for maximum moisture removal.

The other great thing about these models is they look good too, with a nice sleek finish that won’t spoil the ambiance of your spa room.

It’s easy to adjust the settings, so all you do is leave the dehumidifier to run through the preset 24-hour cycle or until the tank is full, at which point it shuts off automatically.

The hOmeLabs Energy Star Dehumidifier can be connected via a garden hose to a drain outlet for continuous draining if you don’t like the idea of emptying the tank yourself.

How do you get a hot tub inside?

Often the problem is not where to position your hot tub but how to get it there in the first place.

The first thing to ask is, “will I get it through the door?” Take a look at this recent article on my website on this subject. I get into average doorways sizes, average hot tub sizes, and the perfect size for a hot tub if you don’t want to have to remove part of your wall.

Just click on the link to read it.

For an average hot tub, you will need a clear opening size of 33″ x 80″. This shouldn’t be a problem for most installations because hot tubs are maneuvered into place on their side.

Unless you are prepared to go to trouble and expense of making the opening taller or wider – which would involve major structural work – you should choose your hot tub based on what will fit through the existing opening.

But what brand of hot tub is best if you will be using it indoors?

I wrote about the best hot tubs for indoor use in a recent article. I get into all the top brands, considerations to think about if you know you’re using it indoors, and a few brands to definitely avoid!

Just click that link to read it on my site.

The other aspect of getting a hot tub inside your home is the physical process of manhandling it through the passages and openings. This is something best left to the installation team – they are the experts in how to lift, carry and maneuver the hot tub without causing damage to the tub or your walls.

Can you put a hot tub inside a garage?

Putting a hot tub inside a garage is an excellent idea as it’s easier to ventilate the room, the floors are typically solid concrete, and it’s easier to run the drain hose outside. Plus the garage door can be left open when the weather is nice, or closed when it’s not.

But there are a few things you have to think about. First of all, aspect.

Garages are designed to house a car, therefore they usually face onto your driveway. At best, you will have a view of the street, but with a little bit of thought, you can screen off the garage from your neighbors to give you privacy.

The next consideration should be the water supply and electricity.

The usual way to fill a hot tub is by using a garden hose, so provided you have a connection nearby, this shouldn’t be a problem.

A 220v tub must be hard-wired into the main electrical system for the house via a disconnect box, which cuts off the electrical supply in the event of a fault such as a short-circuit. If your garage doesn’t have a suitable supply, then you will have to install one.

Having established that you can get water and power to your hot tub, you then need to think about how you get to your garage from the house. Running down the driveway in a robe in full view of the neighbors isn’t ideal, so you might want to think about how this is going to work as well.

But for an attached garage when you can enter from the house, that’s no problem.

Do you need a floor drain for an indoor hot tub?

As a general rule, a floor drain is not necessary for an indoor hot tub. However, access to a water source that can accommodate a hose is necessary as is a nearby window or door where a drain hose can be run for periodic water changes.

However, if your budget can extend to making internal alterations, you will find significant benefit in installing a floor drain and a water supply, just for convenience. You can position your hot tub over the floor drain for direct emptying or a few feet away if you use a pump.

Plus, in the event of a leak, cleanup will be far easier.

A word of warning! A submersible pump can drain 2,000 gallons of water in one hour, emptying a 300-gallon tub in less than 10 minutes. That’s a lot of water over a short time, so you need to size your floor drain to match this.

You will also need a floor drain with a removable cover so that the pump can be connected directly into the drain. Otherwise, you risk the water running out all over the floor.

The next thing to consider is where to connect the floor drain. The best solution would be to connect to the main sewer, but you shouldn’t run it to a storm drain as these lead to watercourses, and your hot tub water will contain contaminants.

Indoor hot tub common problems

From my research, I have compiled a list of common problems and potential solutions to indoor hot tub installations.

Problem Solution Considerations
Getting water in the hot tub If you don’t have a water supply in the room where the tub is located, run a hose to the nearest point. If your water supply has a softener attached, disconnect this while you fill.
Emptying the hot tub Install a floor drain or use a sump pump to pump the water outside. You should not connect a floor drain to storm drains.
Getting rid of steam Use a twin 9” high-velocity fan in a window opening. You may need a separate electrical supply for this.
Floor collapsing because of the weight Have the floor checked out by a professional. The hot tub supplier may have people who can do this for you. A full hot tub is likely to weigh at least twice as much as the standard floor capacity of a house.
Water damage to the structure and finishes Good ventilation and humidity control are essential, but the use of anti-mold paint will also help keep surfaces looking good. Water vapor gets everywhere. Also, spillage can seep through gaps in finishes. Be sure to cover all aspects.
Getting the hot tub into position Doorways and corridors can make life difficult, so leave it to the installation team if you can. Even empty, an average hot tub can weigh up to 1,000 pounds.
Storage for chemicals Ideally, you should have a cupboard where you can store your chlorine, test strips, and cleaning materials safely and away from dampness. It’s important to keep certain materials separately to avoid toxic fumes building up.

Final thoughts

An indoor hot tub can be a great addition to your home, especially if you can combine it in some ways with the outside world. Imagine if you can look out onto your garden, lit up at night, even in the depths of winter.

But you have a lot to think about. Bringing something like a hot tub indoors has its problems, and you will need to address these before making the investment.

I hope this article gives you all you need to help you decide what’s best for you. And don’t forget to click on those links to read other associated articles here on my site.

Photo which requires attribution:

DURING- self leveling concrete is installed over the heating mat. by David Cedrone is licensed under CC2.0 and was cropped, edited, and had a text overlay added.

Jeff Campbell

Jeff Campbell is a 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.

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