Indoor fiberglass pools are becoming increasingly popular with new pool buyers who live in the northeast where the swim season is limited by the climate. A pool room or enclosure adds significantly to the cost of a pool, but it also guarantees perfect swimming conditions year-round. In the northeast, a pool enclosure can turn a 6 month swim season into a 365-day pool party.

Any type of fiberglass pool or spa can be constructed indoors, and the installations can be as simple as a small pool outfitted with swim current systems to large pools for lap swimming. Many people add changing rooms, showers, exercise facilities, steam rooms, saunas, wet bars and other amenities to their indoor pool installations to create a health spa atmosphere. The possibilities for indoor swimming pool ideas are limited only by imagination and budget.

Indoor Pool Construction

The best time to plan for an indoor pool is during the design and construction of a new house. With the right architectural help, however, it may be possible to seamlessly add an indoor pool to an existing home. Either way, it is important to work with an architect or builder who has a lot of experience designing indoor pool rooms.  To do it right, you need a complete HVAC system and that takes someone who knows what they are doing.

Whether a pool is destined for indoors or outdoors, most builders will construct it the same way with one major exception: an outdoor pool deck slopes away from the pool to keep debris and runoff from entering the pool, whereas an indoor pool deck slopes toward the pool to keep water away from walls. Because an indoor pool and equipment does not have to deal with the process of closing and winterizing, the customer saves the time and money of winter closings, winter safety cover and the opening of a green pool in the spring of each season.

Architecturally, an indoor pool room may look like the rest of the house, but in terms of engineering, it is quite different-especially when it comes to heating, ventilation and choice of building materials, which are key to a long lasting structure and ensuring comfortable humidity levels. In some cases, you can expect to pay as much for the air quality equipment as you do for the pool.

Indoor Pool Ventilation/Humidity Control

I can’t say enough about this subject because taking short cuts here can lead to disastrous results. The amount of humidity that can be released from an indoor pool can be staggering.  If typical building materials such as wood studs, standard drywall and components that contain metal are used without an engineered HVAC humidity control system, the results will appear rapidly.  Mold will begin to form on wall surfaces, any windows or doors will become covered with water droplets and any metal or steel components will begin to rust even those painted will suffer the negative effects.

Evaporation and humidity can be reduced dramatically by using an automatic pool cover which can cut evaporation by 50 percent.  An automatic cover is the most effective tool for reducing dehumidification costs.  Along with the added benefits of retaining pool water heat, they provide a 100% barrier to accidents and drowning when closed. They also save on chemical costs and chemical usage when the cover is closed.  I would note that one caution is to be careful with automatic chlorine feeders or salt systems be turned down or off when the cover is closed to prevent the buildup of high levels of chlorine which in some cases could create toxic over chlorinated pool water which can burn skin, bleach bathing suits etc…

Indoor Pool Equipment

Do not underestimate the amount of space you will need for the equipment room. For this, you may want to rely on the pool builder’s expertise, not the architect’s. The pool building professional knows the space needed for the equipment desired which can make for impossible working conditions down the road if equipment ever needs to be repaired or replaced if not designed with enough space to operate and maintain. Also, if the pool is going to be maintained by a service company, consider having the room accessible from outside so that service techs do not have to go through the home to access the equipment.

The type of sanitizer also needs consideration.  We have all been to hotels I am sure where you can smell the chlorine from the pool all the way down the hallway.  We have found great success in using salt systems to generate natural chlorine while giving the bather a smooth silky feel on the skin without the overpowering odor of chlorine.

Indoor Pools with Retractable Enclosures

There are a number of companies out there who make retractable rolling or sliding roof and wall units.  Some companies such as Roll a Cover, based in Connecticut make a very quality high grade retractable cover for many industries including the pool and spa industry.  These covers can be free standing or connected to the home by means of a “lean to” design.  While these enclosures are not as efficient in terms of keeping heat in and cold out due to their design.  They employ weather stripping and other sealing methods where moving panels and components travel during retraction of the cover.  Unlike a stationary enclosure, they do offer the ability to open or retract the cover during the summer months when you may want to have the enclosure or room open.  They can be designed with all clear panels, or some of the panels can be tinted for privacy and all of the materials are made from materials such as high grade aluminum, plastics and stainless steels suitable for wet environments. They can be designed with doors and in the northeast designed for wind and snow loads to meet applicable building codes.  Lighting and electrical requirements have to be independent of the enclosure portions that can open or retract for obvious reasons.  For existing pools, a retractable enclosure may be a cost effective alternative to construction of a building when you factor in all the other costs.

Indoor Pool Lighting

Incorporating lots of skylights, windows and sliding doors lets natural light flood the space, but when the sun goes down you will need adequate lighting for nighttime enjoyment and safety. A combination of underwater lighting and wall sconces typically provides sufficient and attractive illumination. Avoid overhead lights, because the bulbs are too difficult to access when they need changing. If you want lighting near the ceiling, consider LED which have long life and energy efficient. The lighting should be subtle-just enough to create the right ambiance. If it is too bright, it could draw unwanted attention through the windows.


Many people believe that you can construct a indoor pool room for the same cost as an addition.  When you factor in the other costs such as HVAC system etc the cost per sq. ft. can range between $175-$300 per sq. ft.  A retractable enclosure in likely to be more in the $125 per sq. ft. but many options and accessories can cause the cost to edge north of that.  Whatever you do, the best advice is to use a pool builder and architect that has experience with these kinds of projects and remember, you always get what you pay for.



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