Indoor swimming pool climate control

The real problem is moisture

Warm pool water evaporates all the time, and more so when people are swimming. That moisture goes into the air of the pool hall. If it is not removed, humidity climbs and the moisture condenses on the coldest surfaces: windows, roof glazing, steelwork, the underside of the roof and the inside of walls. Over time that leads to mould, rotting timber, corroding fixings and damage that is expensive to put right.

So a pool hall needs dehumidification first, and its temperature controlled second. The air temperature is normally kept a little above the water temperature, because cooler air over warm water speeds up evaporation and makes swimmers feel cold when they get out. That is why ordinary air conditioning, set to cool the room, is usually the wrong tool.

What a pool hall system does

• Removes moisture at the rate the pool gives it off, using a dehumidifier or controlled ventilation, or both.
• Heats the air to the right level above the water temperature.
• Moves air across cold surfaces such as glazing, so condensation does not form there.
• Brings in fresh air to dilute the by-products of pool water treatment.
• Recovers heat where possible, so energy taken out with the moisture is put back into the air or the water.

A pool cover when the pool is not in use cuts evaporation sharply and makes every other part of the system easier. It is often the cheapest improvement an existing pool can make.

What we do, and what needs a pool specialist

Purpose-built pool hall dehumidifiers and air handling units are specialist plant, designed from the pool area, water temperature, use and building. They are usually designed and supplied by pool plant specialists, and we are clear that this is not our core work. If your pool hall needs one, we will say so on the survey.

What we can do around a pool is:

• Ventilation and heat recovery for changing rooms, showers and plant rooms.
• Air conditioning and heating for gyms, treatment rooms, offices and lounges next to the pool. See gym and leisure air conditioning.
• Air-to-water heat pumps for heating, as MCS certified installers, where the project suits one. Pool water heating has its own design needs, which we discuss on the survey.
• Servicing and F-Gas work on refrigeration circuits we are able to work on, by our F-Gas certified engineers.

Home pools and pool rooms

Home pools in extensions, outbuildings and basements are where moisture problems most often show up, because the room was built like a normal extension. Signs that the pool hall is not under control include windows streaming in the morning, mould on ceilings, a heavy chemical smell and rust on fixings. If you are planning a new pool room, the best time to get the climate control right is at design stage, when insulation, vapour control and glazing are chosen with it in mind.

We can look at an existing pool room, explain what we see, and help with the parts that are within our services. For the pool hall plant itself, we will be straightforward about whether you need a pool specialist.

Hotels, clubs and leisure centres

In commercial pools, the pool hall plant usually sits alongside a lot of other building services: changing rooms, gyms, spas, cafés and offices. That is where we normally fit in, with comfort cooling and heating, ventilation and maintenance for the spaces around the pool. In hotels, we often work on guest rooms and public areas as well. See hotel air conditioning.

Spas, hot tubs and steam rooms

Spa areas with hot tubs, steam rooms and saunas bring the same moisture problem in a smaller space, often next to treatment rooms that need to be calm and comfortable. Steam rooms and saunas have their own specialist equipment and ventilation. Treatment rooms, relaxation areas and reception nearby are where comfort cooling and heating fit, and we keep that equipment away from the wettest areas.

Corrosion and equipment choice

Pool air is warm, humid and carries chemicals from water treatment. Any equipment near the pool hall, including outdoor units, ducts, fixings and electrical parts, needs to suit that. We check manufacturers’ guidance on where their products can be used and keep standard air conditioning out of the pool hall itself. Plant rooms with pool chemicals need particular care: equipment should not share air with chemical stores, and we check this before we fit anything nearby.

F-Gas, TM44 and maintenance

Heat pumps and air conditioning near a pool work hard and benefit from regular servicing. Larger systems need F-Gas leak checks, and buildings with more than 12 kW of air conditioning need a TM44 inspection at least every five years. A maintenance contract covers the equipment we look after. Pool projects are priced after survey.