The short answer for Harrow Weald
Planning authority
London Borough of Harrow
Postcode district
Almost all HA3
Conservation areas
Three, the newest from 2023
Scheduled earthwork
Grim's Ditch, 1.3 km
Not sure you are in Harrow Weald? Check your area
Yes, we cover Harrow Weald. It has three conservation areas, and the newest, West Drive and Bellfield Avenue, was only designated on 29 June 2023, so older lists, including the count on Harrow's own Harrow Weald page, can leave it out. The Article 4 directions in the two older areas name individual properties and cover things like porches, roofs, gates and walls, not heat pumps. Most of Harrow Weald is outside all of that, and the commonest home is a semi detached house, 2,293 of 5,021 households at the 2021 Census, where an install is usually permitted development. Two other things are worth knowing. Grim's Ditch, a scheduled earthwork, runs below Harrow Weald Common, and the heat pump permitted development right does not apply on scheduled land. And the northern edge of the ward borders Hertsmere, so an address just over the line is dealt with by a different council.
Wall mounted systems start from £1,995 fully installed, and the price does not change with the postcode.
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The three conservation areas
Harrow's Harrow Weald page describes two areas and tabulates three. The two older ones are covered by the council's 2016 supplementary planning document. The third has only a one page map.
| Conservation area | Designated | Article 4 direction |
|---|---|---|
| Brookshill Drive and Grimsdyke Estate | 1980, extended 1986, 1991, 1997, 2006 and 2016 | Yes, for named properties on Old Redding, Brookshill Drive and Common Road |
| Harrow Weald Park | 1978, extended 1991 and 2006, boundary amended 2016 | Yes, for named properties on Brookshill and West Drive |
| West Drive and Bellfield Avenue | 29 June 2023 | None listed on the council's map |
From Harrow's group page and the map document for each area. The group page mentions an Article 4 direction only for Brookshill Drive and Grimsdyke Estate, but the Harrow Weald Park map lists directions of its own, confirmed in 2017 and 2021, so use the map. The 2023 area is 1 to 41 West Drive, 1 to 29, 31 and 33 to 47 Bellfield Avenue, all of West Drive Gardens, and 128, 130 and 132 Uxbridge Road.
What the directions cover, and what they leave alone
The directions in the two older areas withdraw rights for extensions and alterations, roof changes, porches, outbuildings, hard surfaces, satellite dishes, gates, fences and walls, painting the exterior and, since 2021, demolishing a boundary wall. Many apply only where the work fronts a road, track or open space, and each one lists the properties it covers.
None of the classes in the council's schedules is Part 14 Class G, the one that covers heat pumps, so they do not remove that right. The conservation area rule inside Class G still applies: no unit on a wall or roof that fronts a highway, and none nearer the road than the house.
The 2023 area is the least documented. Harrow's Cabinet report records that its roads had been taken out of a conservation area in 2015, and that Historic England thought the case for designating them was not clearly made. The council's map for it lists addresses and no Article 4 direction.
The north of the ward
Grim's Ditch, also called Grim's Dyke, is a scheduled monument. Historic England's entry covers a 1.3 kilometre length running north east from Oxhey Lane to New Lodge below Harrow Weald Common, and Harrow's SPD says the dyke runs through a number of private gardens and advises checking with Historic England before any works. The heat pump permitted development right does not apply on a site designated as a scheduled monument, so a unit there is outside it.
Historic England's open data shows 25 listed entries inside the ward, three of them Grade II star: Grimsdyke, the Church of All Saints and Harrow Weald House Farm. Permitted development does not apply to a unit on a listed building or within its curtilage. Green Belt, which the SPD records over both older conservation areas, is not a condition of the heat pump right at all.
The ward's northern edge is the Harrow and Hertsmere boundary, with Hertsmere's Bushey Heath ward beyond it, so an address just over the line has a different planning authority. The postcode will not tell you: the ward is HA3 almost entirely, with a handful of HA7 and HA5 postcodes inside it and none starting WD23.
What the housing actually is
Households by accommodation type at the 2021 Census for Harrow Weald ward. The semi detached house is the largest group by some distance.
| Ward | Households | Detached | Semi-detached | Terraced | Purpose built flats |
|---|---|---|---|---|---|
| Harrow Weald | 5,021 | 741 | 2,293 | 776 | 922 |
ONS Census 2021, table TS044, accommodation type by household, as at 21 March 2021, on the 2022 ward boundaries. Only the categories ONS publishes are shown; the remaining households are in converted or shared houses, other converted buildings, commercial buildings or temporary structures.
What applies to you
Your home is outside the three areas
A standard install is permitted development within the national limits: condenser on the rear or a side elevation, pipe run inside three metres, no application. That is most of Harrow Weald.
You are inside a conservation area
The unit goes to the rear, never on a wall or roof facing the road. Check your number against the council's schedule, because the directions name properties, and tell us your address at the survey.
Your home is listed, or the earthwork is in your garden
A unit on a listed building or its curtilage, or on scheduled land, sits outside permitted development, so the council and Historic England come before any booking. Historic England's map for the entry shows the scheduled area.
You live in a flat
922 Harrow Weald households are in purpose built blocks. Freeholder consent comes first, and above the first floor a condensate pump is likely and is a priced line on the quote.
You are near the northern edge
If your address is on the Hertsmere side, Hertsmere decides and Harrow's schedules above do not apply. Tell us your postcode and we will establish the council before we quote.
Your planning authority is London Borough of Harrow
They decide any application for your address, and they publish the conservation area maps you would need to check it. We do not submit applications on your behalf, but we will tell you at the survey if one is likely and give you the unit dimensions and position to put on the form.
London Borough of Harrow conservation areasWhat we would fit in Harrow Weald
Every price is fully installed and includes the unit, the installation, the electrical work and VAT.
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