EPC ratings explained for buyers and tenants

Every property advertised for sale or to let in the UK has to show an energy rating. It is the letter in the little coloured chart, and most people glance at it and move on. It is worth two minutes more than that.

What an EPC actually is

An Energy Performance Certificate rates a building's energy efficiency from A, the most efficient, down to G. It is produced by an accredited assessor who visits the property, records its construction, insulation, heating, glazing and controls, and runs the result through the government's standard methodology. The certificate is valid for ten years.

An EPC is required when a building is constructed, sold or let, and the rating must appear in the marketing material. Some buildings are exempt, including certain listed buildings where the work needed to comply would unacceptably alter their character, and some temporary or very small structures.

How to read one

The headline is the current rating, and next to it sits the potential rating: what the property could reach if the recommended improvements were carried out. The gap between the two is the interesting number. A D that could be a B with loft insulation and a new boiler is a different proposition from a D that is already close to its ceiling because it is solid-walled and in a conservation area.

Below that is a list of recommended measures with indicative costs and savings, and a breakdown of how the property is heated and how well it holds heat.

The one thing an EPC does not tell you is what you will pay. The rating is modelled on standard assumptions about occupancy and heating patterns, not on the last occupier's bills. Two identical flats with the same rating will cost different amounts to run depending on who lives in them. Treat it as a comparison tool between properties, which is exactly what it was designed to be.

Why it matters more to tenants

For renters the rating is not just advice. Under the Minimum Energy Efficiency Standard, a property in England and Wales normally may not be let with a rating below E. Landlords who cannot reach E must register a valid exemption on the national PRS Exemptions Register, and the exemptions are specific and time-limited.

So an F or a G on a rental listing is a question worth asking before you view: either the landlord has registered an exemption, or something is wrong.

Where to find one

EPCs are held on a public register. In England and Wales you can look up any address on the government's find-an-energy-certificate service; Scotland and Northern Ireland run their own registers. You do not need the seller's or landlord's permission to look, which makes it a quick sanity check on a listing before you spend an evening travelling to a viewing.

What to do with the information

If you are buying, use the recommendations as a survey prompt rather than a shopping list. Insulation and heating upgrades are usually the cheapest way to move a rating, and lenders increasingly take efficiency into account in the products they offer.

If you are renting, ask how the property is heated and what the controls are like. A well-rated home with electric panel heaters and no thermostat can still be uncomfortable to live in, and a modest rating on a small, well-oriented flat can be perfectly cheap to run.