A jeweller is a small room with hot lighting, locked cases and a security problem at the back door. Cool the staff under HSE temperature guidance. Keep the indoor unit and its drain off the cases. The outdoor unit must not create a climbing aid, a hiding place or a reason to weaken shutters, alarms or the rear enclosure. Agree that with whoever handles your security before the bracket is drilled. One small split or cassette is the usual scale. This is not a vault design.
Spots that can outgun the people
Spots on a counter can outgun the people as a heat source. Count the lamps, the window sun and the number of staff, then size a small unit. An oversized cassette in a tiny shop will short-cycle, feel clammy and still drip if the drain is casual. HSE temperature guidance covers the staff. There is no legal maximum.
A steady room rather than 16C
Aim air along the shop, not into a stool where someone sits over a pad all day. A steady setpoint beats 16C, which only runs the coil harder. Customer comfort and staff comfort are the same small room. Jewellery is not looking for 16C. You want a stable room and no drips on the cases. Overcooling adds condensate risk.
A mount that must not be a climbing aid
A condenser against a rear window, on a flat roof with a handy climb, or inside a cage that blocks a camera, is a security conversation. The air conditioning firm knows airflow and service access. They do not know your alarm zones unless you tell them. A cage that starves the coil is also a cooling fault. Both constraints go on the drawing. Agree the mount with whoever handles security before the bracket is drilled.
- Include showcase lighting in the load.
- No condensate over cases.
- Do not bridge a shutter, alarm or fence.
Alarm loops and a hole that cannot be undone
Do not leave a ladder, a bracket at knee height, or a new hole through a strong room wall as an install accident. If the only pipe route crosses a protected line, stop and redraw. F-gas work can wait a week. A hole in the wrong wall cannot. The installer needs to know about the alarm before they drill. Walk it with the person who maintains the alarm. A pipe route through an alarm loop or a shutter box is a security fault. Name who will give security sign-off. Do not send stock values. Send the building constraints.
A beep nobody hears after lock-up
Water on a case seal, a velvet pad or an electrical shutter motor is the failure to design out. Test the drain. Prefer a route in a back cupboard. A pump alarm that only beeps in the shop is useless after hours. Ask what happens when the shop is locked. Condensate must not be able to reach the cases.
Quiet talk at the counter
Quiet plant matters if you talk quietly at the counter. Low fan indoors, anti-vibration outdoors, and a position that does not hum into the consultation corner. If you later add more systems, check GOV.UK air conditioning inspections. One shop unit is often outside that duty. The insurer may still want to see the outdoor photos. Ask them. Do not assume a rule. Say whether the door to the street stays shut. This is not a vault design.
Frequently asked questions
Can the outdoor unit sit on the flat roof over the shop?
Only if the structure, the security advisor and planning or the lease all allow it, and the unit is not a climbing aid. Airflow and service access still apply.
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.