On a UK coast the decision is the outdoor coil, not a special indoor badge. Salt spray attacks untreated fins, screws and the electrical box, so the quote should name the corrosion coating on the outdoor heat exchanger and a way to rinse it. The indoor unit can be an ordinary domestic model. Installation is still F-gas work on 230 V equipment, and the outdoor position still has to be checked against Planning Portal conditions in England.
Salt crust on a seafront condenser
Sea air lands on the outdoor coil, the fan, the casing fixings and the pipe flares. Untreated aluminium fins pit, capacity falls, and the fan gets louder as it pushes against a damaged exchanger. The indoor unit sits in room air. Its fascia, filter and brand mark do not coat the condenser.
A seafront wall is harsher than a house a street or two back, and both are coastal jobs. Say which elevation faces the water and the prevailing wind, and whether the house is on the front, an estuary, or set back inland. A courtyard can still collect salt. It collects less.
Name the outdoor coating on the quote
Factory fin treatments, a fuller coating on the outdoor heat exchanger, or a specialist coating applied before the unit is sited all aim at bare metal. Ask which of those is on the model in the quote, and whether the casing and bolts are included or only the fins. A coating slows salt damage. It still wants a fresh-water rinse on a service visit.
- Specify the outdoor coil coating.
- Keep the indoor choice as a normal room decision.
- Leave a path to rinse the fins with fresh water.
- Avoid a pressure washer aimed into the coil.
Mild steel feet streaking the wall
Mild steel feet will rust and streak the wall even when the fins are treated. Ask who applies any aftermarket coat and whether the manufacturer warranty still stands.
A reachable wall out of the worst spray
Choose a lawful wall you can reach for rinsing and for an engineer. If two walls are available, keep the unit out of the worst direct spray. Brackets and bolts should suit a wet site. Clearances stay as the manufacturer wrote them so air and a rinse can both get in.
Stop when the coat closes the fin gaps
A thick layer that closes the fin gaps is a blocked coil, not protection. In England, read the Planning Portal conditions for air source heat pumps before you treat a coastal wall as automatically acceptable. F-gas company certification covers the refrigerant circuit whichever coating you buy.
Frequently asked questions
Will a coastal indoor unit stop salt corrosion?
No. Salt reaches the outdoor coil, fixings and electrics. Choose the outdoor coating and a rinse plan. The indoor unit is a normal room choice.
Does a coated coil never need washing?
A coating slows damage. Salt still builds up. A service rinse with fresh water belongs in the job. Do not jet-wash the fins.
Core buying guides
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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.