Air conditioning in a terraced or back-to-back house in Leeds

Can you fit air conditioning in a terraced house?

Yes. Most terraced and back-to-back houses in Leeds can take a wall-mounted split air conditioner, but where the outdoor unit goes decides whether it can be fitted under permitted development, needs a planning application, or is not practical.

That question matters more in Leeds than almost anywhere else in the country. The Leeds Housing Strategy 2022 to 2027 records 19,500 pre-1919 back-to-back houses still in use, and the city kept building them long after most of Britain stopped. A local history column in the West Leeds Dispatch notes that building them was outlawed in 1909, yet the last one in Leeds went up in 1937. Add the through terraces of Armley, Bramley, Kirkstall and Hyde Park, and a very large share of Leeds homes share at least one wall with a neighbour.

The indoor unit is rarely the problem. The hard part is finding a spot for the condenser that is quiet enough at the neighbours' windows, legal on a front elevation, and safe above a pavement.

What changes between back-to-backs, through terraces and end terraces

The layout of the house sets the options before anyone looks at a brochure. Here is how the common Leeds types compare for the outdoor unit.

• Back-to-back (Harehills, Beeston, Holbeck, Armley, parts of Burley): no rear wall at all, because the house shares its back wall with the house behind. The unit goes on the front elevation, on a gable if it is the end of the row, or on a flat roof if there is a later extension.
• Through terrace with a yard (Hyde Park, Kirkstall, Bramley, Woodhouse): a small rear yard or a ginnel at the back. The yard is the usual choice, but it is boxed in and the neighbours' kitchen windows are often 3 or 4 metres away.
• Through terrace with a garden (Headingley, Chapel Allerton, Roundhay edges): more room at the back, so the rear wall or a ground bracket a few metres from the house is often possible.
• End terrace: the gable wall gives a side position away from most windows, which usually makes the noise test easier to pass.
• Stone terraces (Pudsey, Morley, Otley, Calverley): thick solid walls take a bracket well and pass less vibration through, but core drilling takes longer and the front often faces a street in a conservation area.

The planning rules that apply to a terrace

Since 29 May 2025, an air conditioner that also heats (an air-to-air heat pump) can go on a house in England under permitted development, using the same rules as an air source heat pump. They are in Class G of Part 14 of the General Permitted Development Order 2015, as changed by the 2025 amendment order. A unit used only for cooling is not covered, so the system on your quote should be a reversible model used for heating as well.

Four conditions catch terraced houses most often. A house that is not detached can have one outdoor unit under these rights, where a detached house can have two. The unit must be no more than 1.5 cubic metres, which any normal domestic condenser is well under. In a conservation area, it cannot go on a wall or roof that fronts a highway. And the calculated noise at the nearest neighbouring habitable room window must be 37 dB(A) or lower, worked out using the MCS 020 a) standard.

The 2025 changes also dropped the old rule that a unit had to be at least a metre from the property boundary, which used to rule out many terrace yards and side walls.

The conservation area rule is the one that stops many back-to-back jobs, because the front wall is the only wall and it faces the street. Leeds has around 80 conservation areas, and you can check yours on the Leeds City Council conservation area map. Listed buildings are excluded from permitted development altogether.

If the unit fails one of these tests, that does not mean no. It means a householder planning application. The Planning Portal fee schedule puts the fee for altering a single house at £548 from 1 April 2026. Our guide to planning permission for air conditioning covers the rules for other house types and flats.

Worked example: a front-wall unit on a Harehills back-to-back

Here is the MCS 020 a) arithmetic for a common Leeds case, so you can check what an installer tells you. The formula is: noise at the neighbour = sound power of the unit + 10 x log10(Q / (4 x pi x r squared)) + any barrier correction. Q is the directivity, which is 4 for a unit with the house wall behind it and the ground below, and r is the distance in metres from the unit to the assessment position, one metre out from the centre of the neighbour's window.

Take a mid-terrace back-to-back. The owner wants to cool the front bedroom and the installer suggests a bracket on the front wall beside the bedroom window. The next-door bedroom window is 2.5 metres along the same wall. The assessment position is 1 metre out from that window, so the distance from the unit is the square root of (2.5 x 2.5 + 1 x 1), which is 2.69 metres.

Assume the condenser has a sound power of 58 dB(A). That is an illustration only. Use the figure from the data sheet for the model on your quote, and the highest figure it lists, because MCS 020 a) does not let you use a quiet mode figure. Now 4 x pi x 2.69 x 2.69 = 91.0. Q divided by that is 4 / 91.0 = 0.044. Ten times log10 of 0.044 is about -13.6. So 58 - 13.6 = 44.4 dB(A). That fails the 37 dB(A) limit by more than 7 dB(A).

The house across the street, about 9 metres away, gives 58 - 24.1 = 33.9 dB(A), a pass. The neighbour on the same side is the one that counts.

Moving the unit to the far side of the owner's front door, 4.5 metres from the neighbour's window, gives a distance of 4.61 metres and a result of 58 - 18.2 = 39.8 dB(A). Still a fail. Swap to a smaller condenser with a sound power of 54 dB(A) in that same spot and the result is 35.8 dB(A), which passes. On a back-to-back, the model of outdoor unit can matter as much as the position. Our guide to air conditioning noise explains the decibel scale and barrier corrections in more detail.

If no position and no model passes, the job needs a planning application, and the council will want to see the noise working and the data sheet.

Through terraces: the yard, the ginnel and the back bedroom

A rear yard looks like an easy answer. In practice, yards in Hyde Park, Kirkstall and Bramley are small, walled on three sides, and the next-door kitchen window can be within touching distance of the shared wall. Corners push the directivity up to Q8 under MCS 020 a), which adds 3 dB(A) to the result compared with a flat wall.

A quick illustration with the same 58 dB(A) unit, on the ground against the rear wall (Q4), 3.5 metres from the assessment position at the neighbour's kitchen window. The distance correction is -15.9, so the result is 42.1 dB(A). If the yard wall between the two houses partly hides the unit, MCS 020 a) allows a 5 dB(A) reduction, which gives 37.1 dB(A). That is a fail by 0.1 dB(A), because the limit is 37.0. A wall high enough to fully block the line of sight from the window to the unit counts for 10 dB(A), giving 32.1 dB(A), a clear pass. The barrier must be solid with no gaps; a trellis or hedge does not count.

A wall bracket high on the back of the house, above the yard wall and away from the neighbour's window, is the other common answer.

If the unit would sit on a wall facing a shared ginnel, check who owns the passage and who has a right of way along it before anything sticks out over it.

Pavements, condensate and the Highways Act

Many Leeds terraces open straight onto the pavement, which brings in two rules from the Highways Act 1980 that sit outside planning.

Under section 152, the council can make the occupier remove or alter any projection from a building that obstructs safe passage along a street, and anything insecurely fixed counts as an obstruction. A condenser on a ground bracket on a pavement-facing wall, or a low wall bracket at head height, is the kind of thing that attracts a notice. Mount it high enough that nobody can walk into it.

Under section 163, the council can require the occupier to stop water from the building falling on people using the highway. Split systems make water. The indoor unit drains condensate whenever it cools, and the outdoor unit drips and steams during defrost cycles when it heats in winter. On a street-facing wall, the condensate pipe should run down to a gully or drain, not stop at the brick and drip on the footpath. Where no drain is nearby, a small condensate pump can lift the water to a waste pipe inside.

Party walls, solid brick and pipe routes

Terraces in Leeds are mostly solid brick, one brick or more thick, with no cavity. The installer core drills a hole of about 65mm through the outside wall for the pipes, cable and drain. Stone takes longer again.

Drilling a bracket into a shared wall does not normally need a notice under the Party Wall etc. Act 1996. The GOV.UK party wall booklet says drilling to fix things like shelves or wall cabinets does not need notice. Cutting into a party wall, or anything that could affect its strength or damage the neighbour's side, is different and needs at least two months' notice. Running a pipe chase into the party wall would fall into that category, so keep pipe routes on external walls where you can.

Pipe length is where terraces get awkward. The ideal is an indoor unit on the inside of the same wall as the outdoor unit, with a short run straight through. In a back-to-back, if the room you want to cool is the attic bedroom and the outdoor unit has to be on the ground floor front wall, the pipes run up the front of the house in trunking. That adds labour and visible trunking on the front. Many attic rooms in Leeds terraces have a front dormer, and an outdoor unit on a bracket beside the dormer can shorten the run, provided access for fitting and servicing works.

Check the electrics as well. Older terraces often have a dated consumer unit, and a new circuit for the air conditioner has to meet Part P of the Building Regulations. If the board needs replacing first, that cost belongs on the quote.

One outdoor unit, two rooms: why multi-split suits terraces

Permitted development allows one outdoor unit on a house that is not detached. If you want to cool a front bedroom and an attic room, two separate single split systems would mean two condensers, and the second one takes the job out of permitted development and into a planning application.

A multi-split runs two or more indoor units from one outdoor unit. On a terrace, it often keeps the whole job within permitted development, as long as the single condenser passes the noise test. The trade-off is a larger outdoor unit, which tends to have a higher sound power, so do the noise calculation with the multi-split model, not the single split you first looked at. Our comparison of single split and multi-split systems goes through the cost and efficiency differences.

Terrace rooms are usually small, so do not let anyone talk you into a bigger unit than the room needs. On a terrace it costs you twice: once on the price and again on the noise calculation.

What it costs to run in a small terrace

Small rooms are cheap to cool. Assume a 2.5kW unit in a back-to-back bedroom draws an average of 0.55kW of electricity once the room is down to temperature. That is an assumed figure, so check the input power on the data sheet for the model you are quoted.

Four hours on a warm evening is 0.55 x 4 = 2.2kWh. At the Ofgem price cap average electricity rate of 26.32p per kWh for 1 October to 31 December 2026, that is 2.2 x 26.32p = 57.9p a night. Use the rate on your own bill for a closer figure.

Installation is the bigger number. A domestic installation of a fixed air conditioner that works as an air source heat pump is zero-rated for VAT until 31 March 2027 under HMRC VAT Notice 708/6, and our partner installers apply the 0% rate on domestic jobs. For typical price ranges and what pushes them up, see our air conditioning installation cost guide for Leeds.

Talking to the neighbours before you book

On a terrace, your neighbours live with your outdoor unit as much as you do. There is no legal duty to consult them for permitted development, but a short conversation before the installer arrives avoids most complaints later. Show them where the unit will go and tell them which of their windows the noise figure was worked out for.

If next door already has a condenser near yours, two identical units side by side are 3 dB(A) louder than one, so tell the installer about it.

A badly fitted unit can still be a statutory nuisance even where planning rules were met. Anti-vibration feet, a solid bracket and an annual service all help, whether the house is a brick back-to-back in Beeston or a stone terrace in Morley.

Checklist for a terraced house quote

If any of these is missing from a quote, ask for it in writing.

• Whether the system is a reversible heat pump model, since cooling-only units are not permitted development.
• The exact outdoor unit position, marked on a photo of the wall.
• The MCS 020 a) noise calculation for every nearby habitable room window, including next door and across the street.
• Confirmation of whether your street is in a Leeds conservation area, and what happens if the front wall is ruled out.
• How the condensate will be drained, and how high the outdoor unit and any pipework will sit above a pavement.
• The pipe route, the length included and the trunking colour on any front elevation.
• Whether any work touches a party wall, and if so whether notice is needed.
• The electrical work, who does it and whether it will be self-certified under Part P.
• The installer's F-gas certificate number, which you can check against the guidance on GOV.UK for F gas in air conditioning.
• The VAT rate on each line, which should be zero for a domestic heat pump installation until 31 March 2027.

What to send an installer first

The quickest way to a useful quote on a terrace is a few photos: the front elevation from across the street, the back or yard if you have one, the room you want to cool, and your consumer unit. Add your postcode so the installer can check the conservation area map. You can send these through our free quote form and we will pass your job to an MCS certified partner installer who covers your part of Leeds.