How to improve the EPC rating of a flat
To improve a flat's EPC, start with the recommendations on its certificate, then sort them by who controls each part of the building. Heating controls and lighting are usually yours. Walls, roofs, windows and communal heating often need the freeholder's permission or a whole-block decision. Check your lease before planning any work.
Why flats are different
Flats often start with an advantage. Shared walls, floors and ceilings with heated neighbours mean less surface for heat to escape through. The Office for National Statistics reported a median score of 74 for flats and maisonettes in England and Wales, which is band C.
Position matters. A mid-floor flat with one outside wall usually loses far less heat than a top-floor flat under a roof, a ground-floor flat over an unheated space, or a corner flat with more exposed walls. Two flats in one block can have different ratings for these reasons alone.
The EPC rates your flat, but many of the things that affect it belong to the building. That is the main difference from a house.
Sort the recommendations by who controls them
Find your certificate and go through the recommendations. Then use your lease to work out who decides each one. This is a general guide, and your lease is what counts.
| Measure | Who usually decides | What to check |
|---|---|---|
| Heating controls, radiator valves | You, if heating is your own | Communal systems may differ |
| Cylinder jacket, lighting | You | Usually no permission needed |
| Replacing your own boiler | You, often with consent | Flue and lease terms |
| Internal wall insulation | You, with consent | Lost floor space and moisture risk |
| Windows | Depends on the lease | Frames are often the freeholder's |
| Cavity or external wall insulation | Freeholder, whole block | All parties must agree |
| Roof insulation, solar panels | Freeholder | Roof is rarely part of your flat |
| Communal heating | Freeholder or managing agent | Service charge effect |
Leaseholder and freeholder permissions
Flats in England and Wales are usually leasehold, so read your lease before anything else. LEASE, the Leasehold Advisory Service, says your lease should show which parts you control, and you may need the freeholder's permission for alterations even where planning or building regulations are not an issue. If you are unsure of your tenure, see how to check leasehold or freehold.
- Ask in writing, and describe the work and the products. Get consent in writing before you start.
- Windows are a common sticking point. Frames may belong to the freeholder and glass to you, or the lease may require permission. Secondary glazing may be an easier route, but check first.
- The Energy Saving Trust is clear on cavity walls: you cannot have just your flat insulated. The building owner and everyone involved need to agree to treat the whole block.
- Whole-block work is usually paid through the service charge. In most private blocks, the landlord must run a Section 20 consultation if any leaseholder's share of qualifying works will exceed £250.
- Planning rules differ too. Flats do not have the same permitted development rights as houses, so check with the council before external changes.
If you share a freehold or have a residents' management company, the decision sits with you and your neighbours. The Flats Retrofit Toolkit from the Greater London Authority is written for this situation and recommends planning for the whole building where possible.
Communal heating
If the block has shared boilers or a heat network, your EPC may describe the heating as a community or communal scheme. You cannot replace it yourself, and it may be the largest factor in your rating.
- Ask the managing agent what the system is, when it is due for renewal and whether upgrades are planned.
- Ask whether your flat can have its own controls, such as a programmer or radiator valves, and whether heat is metered or charged through the service charge.
- Raise upgrades with other leaseholders. Changes to a shared system are a building decision, and costs may fall on everyone.
Ofgem began regulating heat networks in Great Britain on 27 January 2026, covering systems from small blocks of flats to large district schemes. If your heating bill is unclear or the service is poor, these protections may help. Under current proposals for new-style EPCs, low carbon heat networks would score C or above on the heating measure.
If your flat has electric heating
Many flats have no gas supply. Because the rating is cost based and electricity usually costs more per unit than gas, electric heating can hold a score down even in a well-insulated flat. The Energy Saving Trust suggests checking that the system and tariff were recorded correctly.
Your EPC may recommend high heat retention storage heaters, which hold heat longer and have automated controls. Heat pumps are possible in some blocks, including shared ground loops, but they usually need the freeholder's agreement and a plan for the outdoor unit or the block's pipework.
If you let the flat or are buying one
Landlords must generally reach E today. If a superior landlord refuses required consent, the third-party consent exemption may apply, and it is due to continue under the planned 2030 rules. Keep the correspondence.
If you are buying, ask about planned major works, service charges and communal heating. See do I need a survey when buying a flat.
Questions, answered
Can I insulate my own flat's walls?
Internally, often yes, with the landlord's consent. It reduces floor space and needs care with moisture. Cavity and external wall insulation are normally whole-block decisions.
Can I put solar panels on my block?
Not on your own. The roof usually belongs to the freeholder, so you would need permission and agreement on how the power is shared.
My freeholder has refused. What now?
Ask for the reasons in writing, and check what the lease says about consent. LEASE publishes guidance, and a solicitor can advise on your lease. Landlords may need to look at the third-party consent exemption.
Do flats in Wales follow the same rules?
Broadly, yes. EPC rules and the current minimum for private lets apply in England and Wales. Grants differ, and housing law in Wales differs in places, so check the local position.