What a certificate is
A lawful development certificate is a legal document from the local planning authority, for Liverpool homes the city council, confirming that a use or a piece of building work is lawful. There are two kinds: one for something already done, and one for something proposed. For a heat pump not yet fitted, it is the second kind, a certificate for a proposed use or development. The government's planning guidance on GOV.UK explains how councils deal with both.
A certificate does not grant planning permission. It confirms that permission is not needed, usually because the plan is permitted development under Class G. If the plan changes after the certificate, the certificate does not cover the new plan.
When it is worth applying
Most heat pumps that clearly meet Class G go ahead without one. A certificate earns its place where the answer is not obvious or where certainty is worth paying for:
- Corner plots and end-terraces, where it is unclear which walls front a road.
- Flat roofs, to confirm the 1 metre edge margin and, in a conservation area, that the roof does not front a road.
- Buildings of flats, especially converted houses and buildings with a commercial ground floor.
- Conservation areas, where the council warns that Article 4 directions may affect some works.
- A planned sale, since a buyer's solicitor may ask how the heat pump was authorised.
It cannot help with a listed building. Class G does not apply to any of the city's 1,569 listed-building records, so a heat pump there needs planning permission, and listed building consent where the work affects the building's character.
What to send
The application has to show precisely what is proposed and why it is lawful. For a heat pump under Class G, that usually means:
- A location plan identifying the property.
- A site plan or drawing showing the outdoor unit's exact position, its distance from the roads that bound the property and, for a flat roof, from the roof's edges.
- The unit's data sheet with its dimensions, to show the volume is within 1.5 cubic metres on a house or 0.6 cubic metres on a block of flats.
- The installer's MCS 020 a) calculation for that position.
- A short statement explaining how the plan meets each paragraph of Class G, and confirming the building is not listed and whether it is in a conservation area.
The street check's result, which lists the paragraphs one by one, is a useful starting point for that statement. Applications can be made online through the national planning portal; the council's planning pages have the details and the current fee.
Timing
If you want the certificate before the installation, apply once the installer has fixed the position and produced the sound calculation, and before you pay a deposit you cannot recover. The installer's design should not change after the application, or the certificate may not match what is fitted.
If you go ahead without a certificate, keep the installer's design, the MCS 020 a) calculation and the MCS certificate together. They are your record of how the heat pump met Class G, and you can still apply for a certificate for the existing development later if a buyer asks.