Running an indoor pool through a Tennessee winter
An indoor pool never closes. That is the point of it, and it is also the whole difference in how one is looked after.
An indoor pool runs year round, so it never gets the winter reset an outdoor pool gets. Expect three ongoing jobs: holding water and air temperature in a sensible relationship, running dehumidification continuously to protect the building, and keeping chloramines down with ventilation and oxidation rather than more chlorine. The water chemistry targets are the same as an outdoor pool; the routine is what changes, because nothing pauses and there is no rain diluting anything.
Air and water temperature are one setting, not two
Hold the air a couple of degrees above the water and evaporation slows markedly, which reduces both the humidity load and the heating cost. Hold the air below the water and the room fogs, the walls sweat and the dehumidifier runs against a problem the thermostat is creating.
This is the one operational habit that matters most and the one most often set wrong, usually by someone trying to make the room feel warm on a cold day.
The cover does more work than the heater
Most of the heat an indoor pool loses, and most of the moisture it puts into the room, leaves through the open water surface. A cover over the hours nobody is swimming is the largest single reduction in both, and it costs nothing to operate.
For a cabin that is used in stretches rather than daily, this matters more still — the pool spends more time unattended than in use, and covered water is a far cheaper thing to keep warm.
That smell is not chlorine
The sharp smell people associate with indoor pools is chloramines — chlorine that has already combined with what swimmers bring in. It indicates a pool that needs oxidation and fresh air, not one that has too much chlorine in it. Adding more sanitiser to fix the smell makes it worse.
The routine answers are consistent ventilation, regular oxidation to break the combined chlorine down, and a rinse-before-swimming habit that removes a surprising share of what forms them in the first place.
- Test more often than an outdoor pool in winter — the water is warm and in use, so nothing has slowed down
- Watch total dissolved solids: no rain gets in, so nothing dilutes, and everything added stays
- Keep an eye on metal fixings and light housings; humid chlorinated air finds them first
Water chemistry does not get a winter off
The targets are the same as any pool — sanitiser, pH, alkalinity, calcium hardness and stabiliser in their usual ranges. What changes is that the water stays warm and in use all year, so demand never drops, and there is no rainfall diluting the pool, so dissolved solids climb steadily rather than being flushed.
The practical version is a routine that runs every week of the year rather than a season of attention followed by a close-down. An indoor pool that is tested in July and forgotten in January is the one that needs remediation in March.
Power, and what happens when it goes out
Mountain power is not perfectly reliable in winter storms. An indoor pool loses its dehumidification and circulation at the same moment the building most needs them, and a room that sits humid and unventilated for several days is a building problem rather than a water one.
It is worth deciding in advance what the outage plan is — whether the equipment sits on a generator circuit, and who checks the room after a long one.
What does a pool actually cost here?
Almost nobody in this trade will answer that in public. We built a tool that does — pick your size, shape, depth and finishes and it returns a planning range for your build, with no phone call first.
Build yours and see the rangeCommon questions
- What temperature should an indoor pool room be kept at?
- The useful rule is air a degree or two above the water rather than a fixed number. That relationship slows evaporation, which lowers both the humidity load on the building and the heat lost from the water. Setting the room cooler than the water to save on heating reliably costs more, because the dehumidifier then works against condensation the thermostat is causing.
- Why does an indoor pool smell stronger than an outdoor one?
- Because the chloramines that cause the smell have nowhere to disperse to. They are a sign of chlorine that has already done its job and needs oxidising away, not of too much chlorine. Ventilation and regular oxidation fix it; adding sanitiser to cover the smell makes it worse.
- Does an indoor pool need to be closed for winter?
- No, and that is the reason to build one. It does mean the care routine runs all twelve months instead of stopping in autumn. There is no rainfall diluting the water and no cold snap slowing demand, so testing and balancing stay on the same weekly footing they are on in summer.