A prayer hall is quiet for much of the week and then densely occupied for a short time. People are on the floor with shoes off, so the air must not draught across that floor and the indoor units must be quiet. A split recirculates. Ventilation is still required for those peaks and is a separate system. This page is about comfort and installation only. It does not give religious instruction. If the effective rated output is more than 12 kW, the operator has the TM44 inspection duty on GOV.UK's air conditioning inspections page. Refrigerant work needs an F-gas certified company.
The hour the prayer hall is full
The design hour is when the hall is full, not a quiet afternoon with two people inside. That peak is a people load and a latent load in a room that may have a high ceiling. Size the full occupancy the committee tells you, and say how long it lasts. A unit chosen on an empty visit will not catch up in the short time that matters.
Shoes outside, dust, and a carpet that must stay dry
Shoes are left outside, so the hall should not be the place a dirty filter blows dust. Maintenance access has to respect the room. The committee should mark any wall that cannot take a unit. This page will not tell you which wall that is. Condensate must not drip onto the carpet. A pump needs an alarm someone will notice before a gathering.
The committee's note of walls that cannot take plant belongs with the ceiling and floor photos. An F-gas certified company does the refrigerant work, with a carpet-safe drain.
Neighbours at the peak, and staff under HSE guidance
Outdoor plant will run at the peak, which may be a lunchtime or an evening when neighbouring houses are in. Anti-vibration mounts, a position off bedroom windows, and landlord or charity consent are the constraints. HSE workplace temperature guidance applies to employees: reasonable comfort, no legal maximum. It is not a rule for how the hall is used.
Frequently asked questions
Will a split ventilate the prayer hall when it is full?
No. It recirculates and cools. Fresh air is still required at peak occupancy and has to be designed as ventilation. A larger indoor unit does not replace that. A full hall needs fresh air. The comfort units will not provide it. Ask for ventilation as its own scope, sized by whoever is competent for that design, and do not let a cooling selection replace it with a larger cassette.
Can the air blow across the prayer hall floor?
It should not. People are on the floor. People sit and stand on the carpet. A jet down the wall at floor level is a draught across the whole front row. Aim along the ceiling on a quiet fan so the room cools without a draught through the occupied floor zone. Compare that sound, not the maximum.
Does this page set how the prayer hall should be used?
No. It is comfort and installation only. The committee tells the survey when the hall is full and which walls cannot take a unit. There is no religious instruction here.
What if the building has more than one closed hall?
Each hall is its own zone. A unit in one will not cool the other through shut doors. The survey should be told the peak for each room that is in scope.
Should a wudu area share the hall coil?
No. A wudu area is a wet room next door. Cool it only as its own zone, and do not pull that moist air through the hall coil.
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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.