Treat a converted chapel as a consent job first. Listing and conservation areas are common, the volume is large, and the roof and the fire strategy may not tolerate plant or new openings. Get listed building consent and planning permission where they apply before any kit is ordered. A bedroom-sized split will not hold a nave. External units and internal pipe routes on historic fabric both need that permission. When consent exists, use an F-gas certified company. In England, start with the Planning Portal heat pump conditions and the listing status, not with a brochure.
Listing and a deposit taken too early
Many chapels are listed, or they sit in a conservation area, or both. An outdoor unit, a core through thick masonry, and trunking on historic plaster can each need consent. Buying the unit first leaves you with plant you may not be allowed to fix. Ask the local authority, and read the Planning Portal notes on air source heat pumps, before a supplier takes a deposit. Check listing and conservation status first. Order kit only after the required consent. Do not fit a split and apply for consent afterwards.
If the building is still a place of worship rather than a house, the consent path may be different again. This page is about a chapel that is now a home. Say which you have.
Nave volume, a gallery stair and a roof that is not a platform
Tall single-glazed windows and a high roof are a large load. Survey the volume. One 2.5 kW wall unit will short-cycle near its sensor and leave the gallery warm. You may need several indoors, a ducted approach, or an honest statement that only the occupied end can be treated. A single small split will not treat a full nave. One wall unit will almost never cool the old nave. Survey that space. Treat the rooms you actually occupy if consent limits what you can do.
Conversions often rely on a fire strategy: protected stairs, galleries, escape windows. Do not prop fire doors so cool air can pass, and do not cut a new opening in a stair enclosure without the building control path that belongs to it. An air conditioner does not replace smoke control or escape.
Chapel roofs and valley gutters are not equipment platforms. Structure, weatherproofing and safe access for service all fail when a condenser is lifted onto a roof that cannot take it. Look for a ground position that consent will allow, screened if the consent requires it, with airflow still open. The outdoor unit can go on the chapel roof only if the structure, the weatherproofing, the access and the consent all allow it. Many roofs cannot take the weight or the openings. Keep plant off roof timbers that were not designed for it. Internal routes on leaded glass, wall paintings or fair-faced brick need the same consent as the outdoor unit. F-gas certification covers refrigerant handling after the building has said yes. Energy Saving Trust's air-to-air explanation is the comfort side, once the fabric is allowed to take the holes.
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.