Permitted development still applies inside a conservation area — that is the bit people get wrong. What changes is where the unit can go. It cannot be fitted to a wall or roof that fronts a highway, and it cannot sit nearer to a bounding road than the closest part of the house. On a normal mid-terrace with a rear yard that is fine, because the yard is behind the building line anyway. On a corner plot round the Downs with roads on two sides, it can rule out every location you would naturally choose, and the honest answer sometimes is a planning application.
The town centre apartments are a separate problem. A block of flats is capped at 0.6 cubic metres of outdoor unit against 1.5 for a house, and one unit for the block-facing installation. That cap genuinely excludes some of the larger models, so the design has to start from what is allowed rather than what is ideal. Where there is a shared service riser, you are also not free to route pipework wherever suits — that is a conversation with the freeholder before it is a conversation with us.
The Victorian terraces off Goose Green are the most straightforward, oddly. Solid brick means a real heat loss number and usually some radiator work, but the rear yard sits behind the building line so the conservation restriction does not bite, and since the boundary rule went in May 2025 the unit can sit against the yard wall.
