Short answer: in most of London, no — solar panels and air source heat pumps are permitted development, meaning no planning application is needed. The exception is conservation areas covered by an Article 4 direction, which removes those automatic rights. London has roughly 1,050 conservation areas across 35 planning authorities, and how many of them carry Article 4 directions varies enormously between boroughs — from two in Hounslow to forty in Islington.
That variation is the whole point of this table. Two identical Victorian terraces, one in Hounslow and one in Islington, can face completely different planning routes for the same heat pump.
| Borough | Conservation areas | With Article 4 | What it means for you |
|---|---|---|---|
| Islington | 42 | 40 | Assume you need permission. Only 2 conservation areas keep permitted development rights. |
| Richmond upon Thames | 72 | Varies by area | Most conservation areas of any London borough, plus protected views. Check before quoting. |
| Ealing | 32 | 6 | Garden suburb estates (e.g. Hanger Hill) are the restricted ones; elsewhere is standard. |
| Hounslow (incl. Chiswick) | 29 | 2 | Only Bedford Park and Gunnersbury Park are restricted. Most of the borough is straightforward. |
| Royal Greenwich | 23 | 6 | World Heritage Site buffer adds scrutiny near the centre; Eltham and Plumstead are easier. |
| Croydon | 22 | 3 | Chatsworth Road's direction names solar panels explicitly — rare in London. |
| Wandsworth | Multiple | Street-level | Directions apply to named streets and house numbers, not whole areas. Check your address. |
| Westminster | 57 | 8 areas | Covers 78% of the borough. But most homes are flats — see the flats warning below, it matters more here than Article 4. |
| Brent | 22 | All residential | The council states every residential conservation area is covered. Assume you need permission. |
| Barnet | ~16–20 | Some areas | Borough-wide direction is HMO-only and doesn't affect solar. Some conservation areas have their own. |
| Hammersmith & Fulham | 45 | Many, property-level | Borough-wide direction covers basements only. Alteration directions apply to named properties within conservation areas. |
| Lewisham | ~30 | Certain areas | Directions apply only to houses in single-dwelling use — the council states flats have no PD rights regardless. |
| Bromley | ~43 | 66 directions | High direction count, but includes HMO and non-householder types. Check what yours restricts. |
| Waltham Forest | ~15 | Mostly HMO | Huge published direction count, but overwhelmingly HMO control in E17 and E10 — not renewables. |
| Outer boroughs | Bexley, Enfield, Harrow, Havering, Hillingdon, Kingston, Merton, Redbridge, Sutton, Newham, Barking & Dagenham and Tower Hamlets all operate conservation-area Article 4 directions, but publish them locally rather than to the national dataset. Most also have borough-wide HMO directions that don't affect solar or heat pumps. Individual Ledger entries in progress. | ||
| Kensington & Chelsea | 39 | 82 directions | Most directions in London. Assume restriction and check your address individually. |
| Lambeth | ~65 | 9 areas | Named: Albert Square, Hyde Farm, Lansdowne Garden, Leigham Court, Park Hall Rd, St Marks, Stockwell Park, Streatham Lodge, Vauxhall. |
| Hackney | ~35 | 4 areas | Named: Brownswood, Well Street, Beck Road, Shacklewell Green. Elsewhere PD rights hold. |
| Haringey | ~33 | 4 areas | Named: Noel Park, Peabody Cottages, Rookfield Estate, Tower Gardens. Muswell Hill, Crouch End and Highgate keep PD rights. |
| Camden | 40 | 19 (easing) | Solar rights restored in Hampstead, South Hampstead and Belsize from June 2026 — see below. |
| Southwark | 48 | Several | One direction covers several conservation areas. Full Ledger entry in progress. |
This catches more Londoners than Article 4 ever will, and it's the single biggest gap in most installer and comparison-site advice.
Permitted development rights apply to houses. They do not apply to flats or maisonettes. That means any external alteration to a flat — solar panels on the roof, an air source heat pump in a garden or on a wall, an air conditioning condenser unit — requires planning permission, regardless of whether you're in a conservation area, regardless of Article 4, and regardless of how modest the installation is.
In boroughs like Westminster, Kensington and Chelsea, Tower Hamlets and much of inner London, flats and maisonettes make up the majority of homes. A homeowner there could correctly establish that their street has no Article 4 direction, and still need a full planning application.
If you're leasehold, there's a second layer on top: your freeholder's consent is usually required under the terms of your lease for anything fixed to the structure or roof, and that's a private contractual matter entirely separate from planning permission. Check your lease before you get quotes — it's the step most people discover last.
Flats aren't out of options, though — balcony solar, communal rooftop systems and battery-only setups all work. See the dedicated guide for flats and leaseholders.
Worth putting a number on the point made above. As of 2026, at least 22 London boroughs have Article 4 directions covering conversion of a house into a small house in multiple occupation — Barking & Dagenham, Barnet, Bexley, Brent, Bromley, Croydon, Ealing, Enfield, Greenwich, Havering, Hillingdon, Hounslow, Lewisham, Newham, Redbridge, Sutton, Tower Hamlets and Waltham Forest have borough-wide directions, with partial coverage in Haringey, Merton and Southwark.
None of those directions have anything to do with solar panels or heat pumps. But because they're borough-wide, a site that simply checks "does this borough have an Article 4 direction?" will report a restriction on every address in eighteen boroughs — which is exactly how the misinformation spreads.
This is the single most common mistake we see repeated on installer and comparison sites: treating "this borough has Article 4 directions" as though it means solar and heat pumps need planning permission there. It usually doesn't.
Article 4 directions are written to restrict specific, named categories of development. In London, most of them target things that have nothing to do with renewables:
Haringey illustrates the point. The council's published Article 4 list is dominated by HMO and warehouse-conversion directions that don't touch renewables at all; householder alteration directions apply in just four conservation areas — Noel Park, Peabody Cottages, Rookfield Estate and Tower Gardens. A homeowner in Muswell Hill or Crouch End reading "Haringey has Article 4 directions" could easily conclude they need permission when they don't.
The question to ask isn't "does my borough have Article 4 directions?" — it's "does a direction covering householder alterations apply to my address?" Those are very different questions with very different answers.
Almost every trend in this table runs toward more restriction. Camden is the exception, and it's worth knowing about if you live there.
Article 4 directions made in September 2010 removed permitted development rights for solar PV and solar thermal panels at the front or side of properties in the Hampstead, South Hampstead and Belsize conservation areas. After Camden declared a climate emergency in 2019, the council moved to replace those directions with new ones that specifically restore solar rights. From June 2026, installing solar PV or solar thermal in those three conservation areas no longer requires planning permission, provided the panels aren't on a listed building, are sited to minimise their visual effect, and are removed when no longer needed. The other restrictions in the 2010 directions remain in force.
If you were told at any point before 2026 that you couldn't fit solar in Hampstead or Belsize without permission, that advice is now out of date.
You may see published figures claiming a borough has hundreds of Article 4 directions — Waltham Forest is often cited at over 800, Southwark at nearly 500. These figures are technically sourced from the government's dataset, but they don't mean what they appear to mean.
The national dataset counts mapped geographic features, not distinct legal directions. A single direction split across several polygons counts several times. Duplicate boundaries count twice. Both the "made" and the later "confirmed" version of the same direction count separately. So a borough that introduced one HMO direction covering many streets can appear to have hundreds.
Waltham Forest is the clearest example: its enormous published count is overwhelmingly one policy — HMO control across Walthamstow and Leyton — rendered as hundreds of separate map features. For a homeowner asking about solar panels, the meaningful number there is close to zero.
This is why the table above reports named conservation areas and direction types wherever possible, rather than raw counts. A count tells you almost nothing; knowing whether a householder alteration direction covers your address tells you everything.
If you cross-check the numbers above against other websites, you'll find different figures — sometimes wildly different. Hounslow is the clearest example: the council's own conservation pages state 29 conservation areas, while third-party planning directories variously list 27, 30 and 43 for the same borough.
There are three reasons for this, and none of them mean anyone is lying:
Our approach: every figure in the table above is taken from the relevant council's own published conservation and Article 4 pages, not from a third-party register — which is why this table grows one borough at a time rather than arriving complete. Where a council's own figure conflicts with a directory, we use the council's. Where we haven't yet checked a borough's records directly, it isn't in the table.
Checked against council sources, August 2026. Article 4 directions can be introduced, revised or revoked — Camden's is a live example — so confirm your specific address with the council before commissioning work.
Usually not. Solar panels remain permitted development in most conservation areas, provided they don't project more than roughly 0.2m from the roof slope and aren't on a wall or roof slope fronting the road where they'd be visually prominent. The exception is a conservation area covered by an Article 4 direction, where those automatic rights have been removed and a planning application is required.
In most London homes, no. An air source heat pump is permitted development if the unit including its housing is under 0.6 cubic metres, sits at least 1 metre from your property boundary, isn't on a pitched roof, and is the only heat pump on the property. On narrow terraced plots the 1-metre boundary rule is the condition most likely to cause a problem.
An Article 4 direction is a formal step a council takes to remove permitted development rights in a defined area, meaning work that would normally not need planning permission does need it. Councils use them to protect the character of specific conservation areas. They can apply to a whole conservation area, or — as in Wandsworth — to individual streets or even numbered ranges of houses within one.
On the evidence in the table above, Islington: 40 of its 42 conservation areas carry Article 4 directions, so most homeowners in a conservation area there will need full planning permission rather than relying on permitted development. Richmond upon Thames has more conservation areas in total (72) but coverage varies by area.
Yes, substantially. Listed building consent is a separate requirement from planning permission and applies regardless of conservation area status or Article 4. If your home is listed, treat any external installation as needing consent and apply for a lawful development certificate to confirm your position before committing to a quote.
You can, but you'll almost always need planning permission. Permitted development rights apply to houses, not to flats or maisonettes, so any external alteration to a flat requires a planning application even outside a conservation area. If you're leasehold, you'll typically also need your freeholder's written consent under the terms of your lease, which is separate from and additional to planning permission. Our guide for flats covers balcony solar, communal systems and battery-only options in detail.
A householder planning application for a single dwelling costs £258 in 2026, and typically takes 8–10 weeks for a decision. If your property is in an Article 4 area or is listed, most installers recommend paying for pre-application advice from the council's conservation officer first — usually £100–£500 depending on the borough — because it establishes whether your specification is likely to be approved before you commit to detailed drawings.
Yes, and Camden is currently doing exactly that. Councils can revoke or replace directions, and several have revisited solar restrictions after declaring climate emergencies. This is why a figure you read two years ago may no longer hold — always check the council's current published direction rather than relying on an older summary, including this one.