u/Ylllllllll

Background

• I own a first-floor flat in a Conservation Area in Camden.
• I'd like cooling for the flat, provided by an air-to-air heat pump which can heat too.
• Proposed install: one external condenser, wall-mounted on the rear (garden-facing) elevation at first-floor level. The rear doesn't front a highway and isn't visible from the street. Unit is under 0.6m³.

My proposed route

Rely on permitted development under Class G, Part 14, Schedule 2 of the GPDO 2015 (as amended) for a block of flats, and apply for a Lawful Development Certificate (proposed) rather than full planning permission.

My reasoning — please sanity-check:

1. Camden's “cooling hierarchy” is hostile to comfort cooling. A reversible heat pump that's also used for heating is “not solely for cooling,” so it can be PD.
2. The conservation-area condition in Class G only bars siting on a wall/roof that fronts a highway — a rear elevation clears that.
3. The height limit only applies to walls that front a highway, so wouldn't apply to a rear wall in or out of a CA.
4. The Article 4 Direction covers front/principal elevations, roofs, hard surfaces and boundaries — not Part 14 heat pumps — so it shouldn't remove the right.
5. I know I'll also need freeholder/leaseholder consent, MCS 020 noise compliance, and Part P building regs.

Questions

1. Is this route feasible?
2. The condition I'm least sure about is “sited so far as practicable to minimise effect on external appearance” for a wall-mounted unit at first-floor height. How much of a risk is that on an LDC, and how do you evidence it?
3. Has anyone actually obtained a heat-pump LDC from Camden (or another London borough) in a conservation area?