Start at the back. A Georgian townhouse usually offers the rear elevation, a closet wing or a lower outrigger as the only serious place for an outdoor unit. The front, with its sash windows and street view, is a consent problem first and an engineering problem second. Many of these houses are listed or in conservation areas. Survey the rear, the party walls and the pipe drop before you choose a room. An F-gas certified company fits the system after that spot is allowed.
The rear elevation before the street front
Listed building consent and planning permission are different questions. In England, Planning Portal conditions for air source heat pumps are the planning test, and they often do not cover a listed facade or a front wall in a conservation area. Listed building consent is about the fabric: the hole, the bracket and the trunking. A freeholder or a residents' association on a divided townhouse can add a third permission. Price the rear. If the rear is a narrow lightwell shared with neighbours, noise and access are the survey, not a footnote. State that the house is Georgian, whether it is listed or in a conservation area, and which floor the room is on. Photos of the rear elevation, the lightwell, the indoor wall and any existing plant, plus the freeholder if the house is split, come before a request for a front-wall install.
Height from a bedroom to the yard condenser
A bedroom on the second or third floor, served from a rear yard condenser, is a height difference and a long vertical pipe. Manufacturer limits are real. A multi-split that tries to pick up the drawing room, the study and two bedrooms from that yard fails when the top floor exceeds the height or the total length. Cool the floor you can reach. Inside, cornices, shutters and window reveals are not places to chase pipes casually. Surface trunking on a principal stair is often unacceptable on a listed interior.
Tall volume, shutters and one reachable room
Georgian rooms are tall. The duty follows the volume you occupy, not a modern house of the same floor area. A first-floor drawing room with shutters closed can still be the room you want for evening use. A top bedroom under the roof may be hotter and easier to sleep in once cooled, if the pipe can reach it. Pick the room you use, then see if the rear spot can serve it. As a 2026 illustration, one rear-served room is often in the low thousands including VAT, while listed consent, scaffold in a well and a long listed-interior route are the costs that overtake the equipment. Ask which rooms that rear spot can serve inside the pipe and height limits, and what consent is required before a hole is drilled. Model codes come after that.
Frequently asked questions
Can the outdoor unit go on the front of a Georgian house?
Rarely. Street elevations, listing and conservation controls usually push the unit to the rear or a lower roof. Get that answer before you design the indoor position around the front sash wall. Assume the front elevation is refused until someone with authority says otherwise.
Will one outdoor unit cool every floor?
Only if each room stays inside the pipe length and height limits for that model, and consent allows the condenser. Tall houses often can cool one or two reachable rooms, not every bedroom. One lawful outdoor spot may only serve some floors.
Do shutters and cornices rule out an indoor unit?
They rule out careless chasing. A clear wall, a closet wing or an agreed trunking route can still take a unit. The survey should say which, in writing.
What if every internal route would harm intact plaster?
The route may be a closet wing or a later service riser. If no route exists without harming intact plaster, that room waits. Party walls on both sides limit where pipes can go.
Can a new indoor unit go on old plant already in the lightwell?
A new indoor unit on an old outdoor unit in the well is usually not a mix-and-match. If plant is already there, the data plates have to show a listed combination.
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.