Moisture in the air (humidity) is the biggest obstacle to overcome when designing or building an indoor pool. Failing to address the evacuation of the humidity can have devastating structural, safety and health repercussions.
Dehumidifiers are expensive, to both install and to operate. They are the ONLY proven means to remove the moisture from the air. Since there are a lot of variables that go into specifying and sizing the correct unit, an expert in this field should be employed. Most of the dehumidifier manufacturers have mechanical engineers on staff who can assist your local mechanical contractor in selecting the proper unit, ducting, and make-up air.
Do not think that you can "brain storm" your way out of buying one of these expensive units. Swimming pool & mechanical contractors have been wrestling with this issue longer than you've been alive. Your hair-brained boot-strap cheapskate methods and ideas of an opening ceiling, sliding walls, lots of windows, air temperature matching the pool temperature, etc. have all been attempted by someone before you. AND THEY FAILED!
An automatic pool cover is the only PARTIALLY "saving grace." An automatic pool cover will reduce the humidity in the room. NOTICE THAT I SAID REDUCE AND NOT ELIMINATE! The installation of an automatic pool cover will only allow for the downsizing of the dehumidifier.
I'm not going to waste time validating why these other "economic solutions" are not sufficient or don't work. You'll have to take decades of experience as the gospel truth. You are not going to come up with any new ideas that haven't already been tried. We've already "been there - done that."
Too much humidity - BAD DOG!! MUY MALO!!
Humidity is formed in the air from the evaporation and splashing that occurs indoors. Mother nature always seeks a balance - think of it as karma, ying-yang, etc.
Humidity in the air can lead to the growth of black mold in the walls of the structure, light fixtures, window & wall coverings, drywall or other surfaces. Breathing the spores of black mold has been linked to respiratory infections, pneumonia and even deaths.
Humidity in the air can also foster bacteria growth. These bacteria once inhaled can also result in respiratory infections. A common ailment is "lifeguard lung," frequently seen amongst indoor lifeguards.
Humidity in the air can also lead to corrosion of structural members of the building. Because we're talking about a vapor (think "gas"), it can permeate & enter walls, ceilings & floors. Corrosive structural elements (steel brackets, i-beams, fasteners, etc.) are all subject to corroding that's occurring inside the walls were you cannot see the damage!
Humidity can also corrode the wiring in the walls, receptacles, switches, light fixtures, or anything else metal within the building. I needn't tell you the dangers of corroded electrical wiring & fixtures. ZAP-OUCH! RUN-FIRE!
Humidity in the air can also lead to condensation inside of the walls, on glass windows, tile surfaces, painted walls and skylights. These water droplets form when the surface temperature is below the dew point in the room. It is practically impossible to heat the glass, painted walls, floors, steel I-beams in the walls, tiled walls, etc. in order to keep them warmer than the air within the room.
In regions of the country where the winters are harsh, you are guaranteed to have condensation UNLESS the air is dehumidified! If the moisture content in the indoor air is low, less water vapor will condensate upon these cooler surfaces.
Condensation will also "pool together" and form run-off. This dripping water can lead to it's own series of destructive forces on your structure. Think about standing inside of your bedroom and misting the room with a garden hose. Do this every day, 24/7. Do you think that you'd start to experience negative effects to the room, walls, floors & it's furnishings?
If you are dead set on having an indoor swimming pool or spa, then you absolutely MUST install and operate a properly sized dehumidifier. A unit that activates automatically is the wisest choice!
Don't think that you're wiser than everyone who came before you. There is no cheap way out.
There are only TWO CHOICES HERE - an outdoor pool or a dehumidifier!
Paolo Benedetti - Aquatic Artist
"Creating water as art."™
Aquatic Technology Pool & Spa©