Conservatories are a popular way to add space and natural light to a property, but they can also influence your Energy Performance Certificate (EPC) rating. Since EPCs measure a home’s energy efficiency, any extension that alters insulation, glazing, and heating demand will affect the outcome.

Why EPC Ratings Matter

An EPC rates properties from A (most efficient) to G (least efficient) and is required when selling or renting. A higher rating makes your home more attractive to buyers and tenants while ensuring compliance with UK property regulations. Learn more about the process on our Services – EPC Assessors in London page.

How Conservatories Can Impact EPC Ratings

  1. Glazing Quality
    Most conservatories feature large glass panels. Single glazing can reduce your EPC score, while modern double or triple glazing improves insulation and helps retain heat.

  2. Thermal Bridging
    If a conservatory is poorly insulated at the junction between the house and extension, heat can escape easily, lowering efficiency.

  3. Heating Integration
    If your conservatory is linked to the main heating system, the EPC assessor will consider its impact. Extending central heating into an uninsulated space may reduce your score.

  4. Solar Gain
    Conservatories can harness solar energy in summer but may cause overheating if not properly ventilated, which can negatively affect energy performance.

  5. Year-Round Usability
    A well-insulated conservatory with energy-efficient glazing and doors can actually improve your EPC rating by making the space usable throughout the year without excessive energy use.

Exemptions for Stand-Alone Conservatories

In some cases, conservatories may be exempt from EPC assessment, particularly if:

  • They are stand-alone structures not permanently connected to the heating system.

  • They have less than 50m² floor area and meet certain exemption criteria.

For more details, see our guide on EPC Exemptions.

Should You Get a New EPC After Adding a Conservatory?

Yes. If you plan to sell or rent after a conservatory extension, a new EPC will be required to reflect the updated property layout. You can check our Pricing page for costs or book a certified assessor directly via our Booking page.

Speak to Our EPC Experts

Conservatory extensions can either enhance or reduce your EPC rating depending on design choices. To ensure compliance and maximise efficiency, our accredited assessors are here to help. Visit our About Us page to learn more about our expertise, or Contact Us for personalised advice.