The main triggers
A valid EPC is normally required when a building is constructed, sold or rented in England and Wales. For a sale or letting, it should be commissioned before marketing if a valid certificate is not already available.
Property advertisements must display the energy rating where the requirement applies, and prospective buyers or tenants must be able to see the certificate.
Selling a home
Check the official register early. If no valid certificate exists, arrange an assessment before marketing. A certificate remains valid for 10 years, so an existing EPC may be usable even if you did not commission it.
If major improvements have been completed, a new assessment can show them, but it is the new certificate — not invoices alone — that updates the official rating.
Renting a home
A landlord normally needs a valid EPC and must also consider the domestic MEES rules. A valid certificate does not by itself prove compliance if the property is rated F or G and no exemption applies.
New and altered buildings
The person responsible for construction must provide the certificate for a new building. Changes that create or alter the number of separately used units can also trigger requirements. Building-control and EPC duties are related but not identical.
Exemptions need careful checking
GOV.UK lists categories that may not require an EPC, including certain temporary, industrial, agricultural, religious and small detached buildings. Listed status is not a blanket exemption. If the decision matters to a transaction or tenancy, check the official wording and obtain appropriate advice.
If you only want to improve your own home
You do not usually need a new EPC simply because you live in the property and are not selling or letting it. You may still choose an assessment to establish a new rating after work.