Air conditioning in Barnet

Barnet's noise limit for outdoor units

Barnet's Local Plan 2021 to 2036, adopted in March 2025, sets a firm rule for external plant. Noise must be at least 5 dB(A) below the background level, measured 1 m outside the window of any room in a neighbouring home. If the sound has a tone or other distinct character, 5 dB(A) more is added. There should be no noise or vibration you can feel through the structure next door.

That's the target we design to. We choose a quiet outdoor unit, keep it away from neighbours' windows, fit anti-vibration mounts and keep it off party walls where we can. Where planning is needed, we provide the noise figures.

Barnet's Residential Design Guidance also says ventilation units and other services that look like add-ons won't normally be accepted. Neat siting and tidy pipework aren't just about looks here.

Hampstead Garden Suburb: two consents

Hampstead Garden Suburb was built between 1907 and 1938 and has over 5,000 properties, many of them listed. Most are covered by the Hampstead Garden Suburb Trust's Scheme of Management. The Trust's consent is needed for any external change, separate from planning permission.

The Trust's design guidance says all air conditioning plant needs the consent of both Barnet Council and the Trust. Units must sit where they can't be seen from the street or neighbouring gardens, and can be screened by planting or a timber housing. Its 2024 retrofit guidance says demand for air conditioning has risen, and that units in sensible, screened positions are likely to be acceptable with a full application.

The Suburb is also a conservation area with an Article 4 direction. We draw up the plans, the screening and the noise data for both applications.

Barnet's other conservation areas

The council says 10 of its conservation areas have Article 4 directions. Most remove rights for alterations to houses, front boundaries and similar works. In Finchley Garden Village and Moss Hall Crescent, the directions also remove the permitted development right for air source heat pumps, so any outdoor unit there needs planning permission.

Outside those areas, a heating-capable unit on an unlisted house can often go in without planning permission under the national rules. Our planning guide explains the limits.

• Hampstead Garden Suburb and Hampstead Village (Heath Passage)
• Totteridge, Monken Hadley and Wood Street
• Mill Hill and College Farm
• Finchley Church End, Finchley Garden Village and Moss Hall Crescent
• Hendon Church End and Hendon The Burroughs
• Golders Green, Glenhill Close and Railway Terraces
• Watling Estate

Semis, terraces and new flats

In the 2021 Census, 28 per cent of Barnet households lived in a semi-detached house and 10 per cent in a detached house. Side walls and back gardens usually give a discreet place for the outdoor unit, and a multi-split can serve several bedrooms from one unit. Loft conversions, common across the borough, are often the first room people want cooled.

37 per cent of households lived in purpose-built flats. Colindale is the borough's biggest growth area, with a target of 5,190 new homes. In managed blocks we work with the managing agent on consent and on where an outdoor unit can go.

The Railway Terraces in Cricklewood are railway cottages built after the Midland line arrived in the 1860s. Small rear yards there need compact units and careful siting.

Parking and access for engineers

Barnet's controlled parking zones each have their own days and hours. For works at an address in a CPZ, Barnet sells a builder's permit, from £50.44 for one month for a named vehicle.

A bay suspension needs at least 7 calendar days' notice and costs £69.63 per bay per day plus a £171.39 admin fee per application. A dispensation to park on a yellow line is £51.90 per vehicle per day, with two working days' notice. If your job needs either, the council's fee is on your quote.

Prices in Barnet

Standard prices for a home install. Screening, Trust or planning drawings and long pipe runs are quoted after the survey.

• A bedroom or study

  2.5 kW wall unit, 5 m pipe, fitted in a day

  from£1,850inc. VAT

• A living room

  3.5 kW wall unit

  from£2,050inc. VAT

• Open plan or a loft

  5 kW wall unit

  from£2,450inc. VAT

• Two rooms, one outdoor unit

  Multi-split

  from£3,650inc. VAT

• Three rooms

  Multi-split

  from£5,100inc. VAT

• Premium range upgrade

  Quieter, more efficient unit

  from£250inc. VAT

Neighbourhoods we cover

We work across the borough, including:

• High Barnet, New Barnet and East Barnet
• Totteridge, Whetstone and Friern Barnet
• Finchley Church End, East Finchley and North Finchley
• Mill Hill, Edgware and Burnt Oak
• Hendon, West Hendon and Colindale
• Golders Green, Temple Fortune and Hampstead Garden Suburb
• Childs Hill and Cricklewood

Barnet questions