# Planning and paperwork: common questions Short answers on what needs permission, what needs notifying, and which documents will still matter in ten years. - Kind: Questions - Category: Paperwork and permissions - Updated: 2026-09-06 - Canonical address: https://ampworth.com/faqs/planning-and-paperwork-questions ## Do I need planning permission for a heat pump? Usually not. Most installations fall under permitted development, which means no application. The condition people most often fall foul of is noise: it must not exceed 37 decibels at a neighbour's window. Listed buildings and conservation areas have their own rules. ## Do solar panels need planning permission? Most roof arrays do not. The usual conditions are that panels sit close to the roof plane and not above the ridge. Listed buildings, conservation areas, and flats all have their own rules, which your council can confirm. ## What is the 37 decibel rule? A limit on how loud a heat pump may be at a neighbour's window or door, not at the boundary, and not at your own house. It is worked out by calculation, not measured, and your installer has to do it before relying on permitted development. ## My heat pump fails the noise check. Is that the end of it? No. It means the current position does not work, not that the house cannot have one. Moving it further away is worth about six decibels per doubling of distance. Bringing it out of a corner is worth three per wall, and a solid barrier in the line of sight can be worth ten. ## Does building control need to know? Yes, but your installer handles it. Both heat pumps and the electrical side of solar are notifiable. You should receive a compliance certificate. If an installer suggests you make the application yourself, ask why. ## What is a DNO notification? Telling your distribution network operator (DNO), the company that owns the wires in your street, that you have connected something that generates electricity. Small systems are connected first and notified within 28 days. Larger ones need approval before connection, and that approval is not guaranteed. ## What is export limitation? If the local network cannot take your full output, you may be allowed to install anyway on condition that a device caps how much you send back. The annual cost is usually small, a couple of per cent, but the quotation should disclose it. ## Which documents matter afterwards? The certificate above all, because it is what grant schemes, export payments, and your buyer's solicitor will want. Then the design calculations, the commissioning records, and the insurance-backed guarantee policy. ## My certificate has not arrived. What do I do? Ask the installer, in writing. Registering the installation is their job and there is a time limit on it. If that does not work, their certification body is the next step. Missing paperwork is a straightforward complaint for them to act on. ## Does any of this affect my EPC? Yes. Both solar and a heat pump feed into the energy performance certificate (EPC) calculation, though how much depends on the assessment method in force at the time. The assessor will want to see the certificate as evidence, so keep it somewhere findable. ## Work it out - [Heat pump noise assessment](https://ampworth.com/calculators/heat-pump-noise): Works out the sound pressure level at a neighbour's window and whether it clears the permitted development limit. ## Sources - MIS 3002, Solar photovoltaic systems: https://mcscertified.com/standards-library/ - MIS 3005-D, Heat pump systems: design: https://mcscertified.com/standards-library/ - MCS 020, Sound and vibration for air source heat pumps: https://mcscertified.com/standards-library/ ## Related - [Installers and certification: common questions](https://ampworth.com/faqs/mcs-and-installer-questions.md): Short answers on what certification means, who checks the checkers, what happens if an installer goes under, and who to complain to. - [Heat pumps: common questions](https://ampworth.com/faqs/heat-pump-questions.md): Short answers on whether a heat pump suits your house, what it costs to run, how loud it is, and what has to change before one goes in.