A changing room needs fresh air as well as a tolerable temperature. Showers throw moisture into a small volume, occupancy swings from empty to packed in minutes, and odour lingers in wet fabric and mats. Air conditioning can cool and take some moisture out at the coil. It does not supply the ventilation rate the room requires, and it will grow mould if the drain and the extract are afterthoughts. Survey moisture, privacy for maintenance, and where the condenser can sit away from members.
Wet towels after a class changeover
Wet floors, towels and a shower stack push humidity up fast. A cooling coil will condense water, which is useful, and that water must leave through a drain you can trust in a wet area. A blocked tray in a changing room is a slip and a hygiene issue, not only a stain.
Extract carries odour, the coil only condenses
Extract ventilation removes moist air and odour and brings in outdoor air. Recirculating the same air through a cassette, however cold, leaves the room smelling of yesterday's class. Ask the ventilation designer for the fresh-air path. Ask the air conditioning installer for the cooling and the condensate. Do not let one quote blur the two. Air conditioning can reduce moisture at the coil if the drain works and ventilation removes damp air. It will not stop mould if extract is missing, the tray overflows, or wet surfaces never dry.
Empty at 10:30 and full at 18:05
The room is empty at 10:30 and full at 18:05. Equipment sized only on floor area misses the body heat and the moisture of a class changeover.
- Cooling and extract are both in scope.
- A short peak can drift a little if the air is moving and fresh.
- Condensate in a wet room needs a reliable route.
- Service access must respect member privacy.
Fluff, corrosion and a condenser away from the entrance
Noise matters when people are changing, not spinning. A roaring fan coil above a bench will be switched off. Look at sound data and at throw, so a cold dump does not hit one bench while the far end stays muggy. Corrosion and fluff are the enemies. Indoor units need filtration you can change without closing the gym for a day, and casings that suit a humid room. Outdoor units need a position clear of member entrances and of the laundry extract. Filters load with fluff and need a contract. F-gas certification applies to the refrigerant work. GOV.UK publishes that certification. If the wider gym cooling is already a large system, check the GOV.UK air conditioning inspections guidance for whether the combined plant crosses the published threshold. The changing room is often a small zone on a larger duty.
A mid-20s policy after a workout
Staff who supervise the floor are at work. HSE's temperature pages deal with reasonable comfort rather than a single legal maximum. Members are customers, and they still judge the club on whether the room feels safe and dry. Write a setpoint policy in the mid 20s rather than an 18C shock after a workout, and pair it with ventilation that actually runs. HSE does not set a legal maximum workplace temperature. Humidity, fresh air and the work rate all sit in that judgement. As a 2026 illustration, a dedicated split for a small changing room is often quoted in the low thousands of pounds including VAT once a pump, a humid-room filter plan and a discreet outdoor position are included. Folding the room into an existing gym VRF can be tidier if the combination rules allow. The survey compares those two, not a domestic bedroom price.
When the gym-floor cassette is the wrong zone
Using the same cassette as the gym floor is the wrong approach unless that unit was sized and ducted, or zoned, for both duties, and shower moisture is not pulled into a floor unit that cannot drain or filter it. A separate zone is the usual clean answer. The same approach is wrong if the quote treats cooling as a substitute for extract. Design both systems.
Core buying guides
Start with these high-intent guides, then dig into the rest of the library.
Related guides
Sources and further reading
How this guide was prepared
This guide was written by the Local AC Installers Editorial Team. We compare official guidance, legislation and established consumer information, separate general information from project-specific advice, and show publication dates and sources. We do not accept installer accreditation claims at face value.