Indoor Hot Tub? Avoid Disaster. 7 Things You Must Know BEFORE Beginning Your Project

Indoor-hot-tubTop Seven Tips for Installing a Hot Tub Indoors

When the fall chill comes to the air, we start getting questions from shoppers who think they might prefer to have their hot tub indoors. Personally, we enjoy soaking outside because it feels more natural, but we can bring the Olympic experience inside if you don’t have a spot on the deck or lawn, or if you’d just rather relax in the privacy of your home or make your hot tub part of a home gym.  

Obviously, the indoor installation comes with a few extra complications compared to the outdoor space, so we’ve put together some issues and answers for you. These tips apply to any hot tub in the Hot Spring family of spas.

  1. PICK THE RIGHT MODEL. The most popular models for indoor use are the Jetsetter and the Prodigy Hot Spring spas.  HOT TIP: For best results, consult with a qualified builder or architect and call us for specifications for which ever model you select. If you’re building a new room, leave a big opening for the hot tub delivery. The best plan is to have the hot  tub installed before you close up that last wall.
  1. WATCH WHERE YOU STEP. Avoid flooring that turns slippery when wet. Believe it or not, about a gallon of water comes with you when you get out of the hot tub, and most of it flows to the floor. Choose a floor material that maintains good traction and drainage when wet. That does not include wood or carpet, which will rot, or “Astroturf” plastic grass carpet, because water can seep under it and rot the base. Best bet is a matte finish, non-slip tile. HOT TIP: Install a floor drain for easy cleanup and for draining the spa.
  1. GO WITH THE FLOW. Even though all Hot Spring, Limelight, and Hot Spot  Spas are portable and require no external plumbing, you’ll need a convenient water source for filling.HOT TIP: Install a hose bib in the room to make those fill-ups easy
  1. DRYWALL, YES DRY WALL.  A tight-fitting cover keeps moisture in the hot tub, but when the lid comes off, the room steams up fast. Cement walls, glass enclosures and cedar lining are among the best choices for wall material. You can also use the water-resistant drywall made for bathrooms and kitchens.  HOT TIP: Install an intact vapor barrier under the wall covering to prevent dry rot of studs and joists.


  1. FAN IN. FAN ON. You’re going to need a powerful, quiet vent fan to get the humidity out of the room fast without disturbing the peace of your hot tub time. That’s the most     important part of saving walls and structural elements from dry rot. The usual “builder’s special” fan won’t do – it’s noisy, and before long its rust will be staining your walls or ceiling.  We’re fans of the Xpelair brand from Coast Products, 954 Elliott Avenue West, Seattle 98119, (206) 285-5120. Xpleair fans are whisper quiet, won’t rust, and are sized to handle the space in your room. They come as ceiling, external wall or window mounts. Be sure to get one with a timer, thermostat and humidistat in one unit. HOT TIP: Call an HVAC contractor for help to get the right size, pick the right place in the room, and install the fan correctly.
  1. HEAT THE SPACE. To minimize moisture condensation, make sure the room is adequately heated.  HOT TIP: A ceiling fan will enhance air circulation.
  1. NO SMELLS ALLOWED! There’s nothing worse than the dank odor of chlorine filling your house, and it will get out of the hot tub room every time even if you use the fan. HOT TIP: Odorless SilkBalance or the new ACE salt system is the only way to go for sanitizing indoors.
  2. CALL OLYMPIC BEFORE YOU BEGIN YOUR PROJECT.  Best tip of all.  We’re a phone call away with 34 years of installation experience inside and out. We’re here to help.  A quick phone call can save you years of grief and boatloads of money. 1-800-448-8814. We make it easy to take it easy!                                                                                                                                                                                                                                                                                                    RES EST SERVA VOLUPTAS Pleasure is serious business.


Don Riling

Author: Don Riling

Don Riling is the President of Olympic Hot Tub and has been an active member of the hot tub industry for over 20 years. As the company’s owner since 2016, he has continued Olympic’s legacy of promoting health & wellness through hot water therapy.

37 responses to “Indoor Hot Tub? Avoid Disaster. 7 Things You Must Know BEFORE Beginning Your Project

    1. Vivian:
      YES! It really is odorless. And, it does not dry your skin like chlorine. Your skin fells really soft after soaking in SilkBalance.
      So many children and adults have sensitive skin. By using SilkBalance they’re able to use their hot tubs and not suffer from itchy, dry skin.
      I suffered so much in the winter from dry skin that I couldn’t use my hot tub. What a relief when I switched to SilkBalance!
      Read more on SilkBalance:
      Thanks for writing.
      Happy hot tubbing,

  1. Thanks for these great tips. All good stuff! I am building an indoor spa room at our new fly fishing lodge located in Nor Cal on the Trinity River. It rains a lot there, so we want the spa indoors for client comfort. I was planning to use natural slate for the floors and walls. Do you think this is a bad idea? The floor will be slopped and drained as you suggest and I am using hardy backer board with a plastic vapor barrier behind the boards for the walls. For the ceiling was planning to use T&G knotty pine with a good marine grade varnish on it (SPAR VARNISH or other?). Any comments are greatly appreciated. Also you don’t recommend the Grandee or Vista from Hot Springs Spas? Why?

    1. Hello Mike:
      Glad you found the blog post helpful. Your plans sound spot on. I’ve been along the Trinity River. You’ve certainly chosen a beautiful spot. SPAR varnish is a good choice. I did not see mention of a fan. That is the #1 thing to install to overcome moisture.
      I am baffled by your comment that I don’t recommend the Grandee or Vista! Are you serious? I have been a Hot Spring dealer since 1992 and absolutely believe in the brand and everyone of the models. The Grandee is so popular with our sales staff & customers that it’s our 3rd best selling model. I would recommend the Grandee for your lodge not only for the size, but the open seating. You didn’t mention water care: SilkBalance is the way to go for your use.
      Good luck & send me a photo of your indoor spa room when you’re finished. I’ll feature it on the blog.
      Best wishes,

  2. Thanks for these great tips. I am in the process of an indoor hot tub. Your tips are exactly as I have designed with the exception of floor drain. Great tip! There will be one. Thanks again. Bob brooks

    1. Hi Bob:
      Thanks for writing.
      So glad my tips for an indoor hot tub installation were helpful.
      Good luck with your project.
      Happy soaking!

  3. Well I own a magazine in the Spa industry, myself and the the editorial team always look to Alice for advice and great ideas. We just bought a condo with an oversized master bathroom with 12 foot ceilings. Considering installing the Hotspring TX. This was really helpful advice and will spec in the Xpelair fans for venting. The other challenge will be to build out custom spa cabinets to match the rest of the master bath cabinetry.
    Thanks again Alice

    1. Hi Peter:
      So great to hear from you. Thanks for your kind words. We miss your yearly visits to Olympic.
      Glad that the post was helpful. Send me a photo when you’ve completed the remodel.
      Sounds like a dream master bath. You deserve it!!

      All the best to you,

    1. Hello Christy:
      Thanks for writing.
      Here’s our advice:
      FAN IN. FAN ON. You’re going to need a powerful, quiet vent fan to get the humidity out of the room fast without disturbing the peace of your hot tub time. That’s the most important part of saving walls and structural elements from dry rot. The usual “builder’s special” fan won’t do – it’s noisy, and before long its rust will be staining your walls or ceiling. We’re fans(pun intended!)of the Xpelair brand from Coast Products, 954 Elliott Avenue West, Seattle 98119, (206) 285-5120. Xpleair fans are whisper quiet, won’t rust, and are sized to handle the space in your room. They come as ceiling, external wall or window mounts. Be sure to get one with a timer, thermostat and humidistat in one unit. HOT TIP: Call an HVAC contractor for help to get the right size, pick the right place in the room, and install the fan correctly.

      Best wishes,

  4. I have learned why an exhaust fan was installed in the hot tub room and will buy the SilkBalance when I feel secure enough to operate the hot tub we have acquired in our new home.

    My husband and I just bought a home that already has an indoor hot tub room. I have several questions.

    I am in the process of fixing up the room and bringing it current; the room has a musty smell, the glass on the windows has a white film between the double panes. However, there is no sign of mold and the house passed inspection. I am going to clean the non-skid carpet with a carpet cleaner; clean the walls with a mold protection and paint the walls (suggestions on the paint to use); and the other thing is how to care for the wood that goes around the tub.

    Another question is there a professional who is able to come tell us how to use it, how to care and maintain a tub? Is there anything else important I need to know before I start this project?

    Thanks for this website and blog,

    1. Hello Brenda:
      Thanks for writing.
      Congratulations on your new home.
      I am worried about the musty smell in the room.
      If I were you, I would remove the carpet altogether & replace with
      a non-skid tile for easy cleaning.
      Make sure your walls are the type of drywall for kitchens & baths and use
      enamel not latex paint for the new paint job.
      Sand the wood around the tub, stain it and unless your stain is a 1-step product with polyurethane, apply a wood sealer or waterproofing over the dry stain, to protect it from moisture and dirt.
      Not sure where you live, but in the Puget Sound area, Olympic Hot Tub has a valet team who does water care lessons in your home.
      You’ll learn exactly how to care for and maintain your new hot tub. It’s money well spent and will save you hours of guesswork.

      Sounds like you’ve asked all of the relevant questions.
      Good luck with your project!!

      If you do need additional help, let me know!
      Best wishes,

  5. Want to get all the proper way to make a room for a hot tub. I already have a hot tub on the deck. Can I make an enclosure with the present deck set up? Any ideas would help

    1. Hi Carl:
      Thanks for writing.
      My thought is that trying to make an enclosure on top of an existing deck would be more costly & difficult than
      starting from scratch. If you want an enclosure, your best bet is a Covana.
      with the screens, it’s like you’re inside, but without all of the hassle of building, ventilation etc.
      The Covana is safe, secure and provides a great cover if you don’t want to hot tub in the rain. It would be far less expensive than trying to build an enclosure.

      Happy soaking!

  6. Thanks for your helpful article. I gather the fan and heater are needed to manage the humidity in the room. Does the fan need only be on when you are in the spa? Also with the room heater is that just turned on when it is cold or does it run all the time? Does having the spa cover on when not in use reduce the need for the fan/heater to be on when you are not in the spa?
    Thank you

    1. Hello Jillian:
      The good spa cover is the best way to reduce humidity. Always keep the hot tub covered when not in use.
      Always run the fan during use and for about 5 minutes after you get out to make sure all humidity is cleared out.
      Depending on where you live-really cold climate??-then heating the room might be a good idea in winter. Otherwise, I don’t think
      you will need to heat the room.
      When a room is 70 degrees or so and the hot tub is 102-104, you’ll only be able to stay in a short time before getting too hot.
      Most of the body’s cooling is through the head and shoulders. When the room is hot & the spa is hot, there is not that cooling effect
      that you get with being outdoors in a cooler ambient temperature.
      Best wishes,

  7. Very good article. We have an indoor hot tub which we inherited with the house we just bought. Can we move this tub outdoors? Or are indoor hot tubs only for indoors?

    1. HI Tracy:
      Thanks for writing and your comment on my blog post on indoor hot tub installations.
      Without know the brand of hot tub you have, I can’t help you.
      Check to see if it is insulated..that should mean it’s good to go outdoors.
      Good luck,

  8. Good Moring Alice

    I have had my 2002 Hot Springs Solana TX since day 1 and I love it. I was living in a ground floor apt when I first purchased it, used it every day for five years never had any humid problems. kept an eye on the humid level in my apt plus the spa was located next to my sliders which I opened in the summer months. Winter it was great when adding heat to my apt. I live in south Dakota , winters can get really cold.

    I bought a home in 2005 moved my spa to a cement patio -wanted to try the outdoor experience. Have done this going on 5 years, now I would like to move it in doors for the winter. My reason, cost. It is very expensive maintaining temp when its 15 degree or even below zero and I have limited income now. What is your advice for moving it in doors during the winter months?

    1. Hi Mary:
      Thanks for writing. So glad you are loving your Hot Spring 2002 SX. That’s a long time and certainly shows how well built the Hot Spring line is.
      Moving indoors for winter certainly will save you some electrical costs and will probably be more enticing to use regularly when you have 15 degree of lower(!) weather.
      Just make sure you have adequate ventilation!! And, don’t put it on carpet or any other moisture wicking surface.
      Continued happy soaking,

  9. I really liked this, but I ( I go to school) am creating my dream room ( online) and i chose to have a jacuzzi in my room! But i have to find/ research about having one in my room and how it can be useful… and suggestions?

    1. Hello Hend:
      The blog post outlines the steps you need to take to have a hot tub/spa in your room.
      May not be practical in a dorm room, though!
      Good luck with school.

  10. We built a room for our new hot tub, cedar interior all windows. I had beautiful bamboo blinds for privacy but found they got moldy. What could I use over the vinyl Windows that would be attractive and not get moldy?
    We live in westerns Mass. So winter weather is a factor.

    1. Hello Susan:
      I have two questions for you:
      Do you have a really good fan that exhausts to the outside AND do you you use it when you hot tub?
      Sounds like the mold problem is really a dehumidification issue on one hand.
      On the other, have you looked into Hunter-Douglas Palm Beach Shutters with stainless steel hinges? They’re made of UV resistant compounds and are available in a 2 3/8″, 3 3/8″ or 4 ½” louver size. The Palmetto model gives the traditional tilt bar design. The Lantana model allows the louvers to be tilted in any position without the need of the tilt bar to give a very contemporary look. Go to the Hunter Douglas website for more details and

      Good luck with ending the mold and happy hottubbing,

  11. We just got a thermospa and on the side of the house we had an awning good up the house was built in 1934 river rock for the bottom so we had a contractor to build he called it a floating deck but he said he could drive a car on it and then it was pressure treated water resistant wood now he has put the wall up which basically is one long wall and one short wall but was wondering what type of good to use on the inside because it’s kind of cold up here in Hendersonville North Carolina and yes I know dawning is going to lose some heat but we just couldn’t afford to replace all of it he mentioned something called Hardie board but thought that might be a little expensive and spend 3 months and it’s only partially done and yes we were going to put a fan in Spa is working we’ve used it but it seems like we’ve been to the bottom of the list now as the getting it finished also where the door would go its going to have to be trimmed almost 5 inches and we want to put a big piece of glass in should I hit the antique stores and such looking for a solid door so I could cut it and put the glass in or look at having one just built like I said I’m looking for the best thing to use on the inside because right now you open it up and the room is total screen and cold all they have is sething up, and two windows I would really appreciate anything you have to say what it would be easier to use the green board and paint it or by the hardy board or something close to it I’m not saying I want to go to but the spa was expensive thank you very much Mary

    1. HI Mary:
      Yes, you did pay a lot for that Thermospa.
      Now you want it in a place that is moisture proof.
      I would heartily recommend Hardie board. Green board is moisture resistant, but NOT waterproof.
      You’re going to a lot of trouble to make this a great setting. Do it right the first time and
      you won’t have to worry in the future!
      Don’t forget the fan recommendation and to use it every time you hot tub. That’s vital to keeping
      dampness and mold from spoiling your indoor experience.

      Good luck & happy hottubing,

  12. Thank you for this article. We are in the process of finishing our hot tub room (a redone boat house) and are looking for an option of what to put on the concrete floor to provide a moisture resistant and non slip surface that will also cover up some of the small hairline cracks in the concrete….so something with texture. Do you have any suggestions for us?

    1. Paula–While I’ve been in the hot tub industry for a loooong time, I’ll tell you I’m no expert on something like this! I’d reach out to a contractor or a concrete company for a recommendation from someone in the know. Best of luck with your project!

  13. We just had our patio enclosed so that we could use our hot tub during the winter. When we had the room built 12 x 50 with 8 ft ceiling. We had 6 large windows and a door installed as well. We also had a vent installed for evaporation.

    Right now I’m in the process of adding heat to the room ( one of your recommendations) as well. And reason for this is the condensation from the hot tub when the lid is off.

    My next project is an exhaust fan where the vent is, but I see you recommend a place. I looked at there website and I am not sure which area to go to to see what’s available for what i could possibly need.

    Any recommendations for my size room ?


    1. Jim–Removing moisture from an enclosed space for an indoor hot tub installation is key. While we recommended a product called Vent Axia for years (, I imagine there are likely some other good options today. I would speak with someone at a home improvement store and find out what product they may have available that will work as well.

  14. Thanks for your tip about installing a powerful fan to get the humidity out of the room fast if you install a hot tub. I imagine that working with a contractor who has experience installing indoor pools and hot tubs already would be a good idea, since they would know techniques like this. I bet this advice would apply to things like home extensions and sun rooms as well.

  15. hi i am getting a summer house erected made of pressurized cedar wood, there will be no electric in it and i will have an inflatable spa in it. i live in a cold climate and will be able to track in a blow heater in but definitely no fan im afraid. i will have four cut out holes as vents,one on top of each wall either side and be able to open the door and windows to help get rid of some condensation. i was wondering should i leave the floor alone or could i put a roll of linoluem down to help protect the wooden floor, also what should i treat the wood with on the inside to help protect it and do you think this set up would be adequate enough to keep the wood safe.

    1. Emma–Your contractor should be able to answer these questions for you and get the room designed correctly for a hot tub. Best wishes with your project!

  16. Alice, we are planning new home in MI and want a hot tub enclosure. Builder already mentioned some of the items you highlight (fan, venting, moisture resistant products) but he couldn’t answer if he ever seen a hot tub in greenhouse (with plants like orchids). Will hot tubs harm plants?Is it about enough ventilation when it’s open or is not a good idea to combine two and I need to plan a separate conservatory space?

    1. Martha–Thanks for the question. I know that we have had some customers place a hot tub in a greenhouse in the past. I would consult with the company you intend to use for your greenhouse installation and get their advice.

  17. Sir I have my hot tub in a 12’X 7′ room and have a side exhaust and a ceiling exhaust. When using the tub, you can’t stand the fumes and cough and turn the water circulation back off. What can I do besides moving it back outside? Thanks and hope for some advice that might help.

    1. Arlon–Sounds like you need a water care system that requires less chemicals. I would contact the hot tub company that services the brand you have and determine if there are some alternatives that would allow for fewer chemicals. Some odor from hot tub water is due to water chemistry being out of balance. Make sure your alkalinity and pH levels are tested and balanced weekly, and that your water is shocked on a regular basis.

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