Conservatories are some of the most popular home improvements in the UK – they’re quick and you don’t need planning permission to build one. A well-built conservatory can even add value to your home. But will it impact your Energy Performance Certificate (EPC)?

What is an Energy Performance Certificate?

An EPC measures how energy efficient a property is. To issue your house with an EPC, a domestic energy assessor gives your property a number of points between 0 and 100 based on various factors around your home. These points translate into an EPC rating from A (highest, most efficient) down to G (lowest, most efficient). You need a valid EPC to sell or rent your home in the UK.

Conservatories and EPC rating

Whether a conservatory will affect your EPC depends on its construction.

  • Separated conservatories. The conservatory is separated from the house by external quality walls, doors, or windows. An example here would be if the door separating the two would otherwise open to the outside, such as a double glazed or PVC door.
  • Integrated conservatories. There is no real separation between the conservatory and the main house. An example here would be a conservatory that is used as an extension of an open-plan living space, with no door separating the two.

How separated conservatories affect your EPC rating

A separated conservatory has no impact on your EPC rating. A domestic energy assessor will not include it in calculations for the EPC rating of the property, regardless of whether it is heated or unheated, single or double glazed.

How integrated conservatories affect your EPC rating

An integrated conservatory will impact your EPC rating. A domestic energy assessor will measure the area of the conservatory and work out the length of its exposed perimeter. The assessor will also note whether it is single or double glazed, as this affects energy efficiency. Photographs are taken as evidence so no paperwork from the conservatory manufacturer is required during the EPC survey.

A conservatory typically only has a small effect on your EPC rating. In our experience as domestic energy assessors in Belfast, a conservatory only reduces the final rating figure by 3 or 4 points.

Should I upgrade my conservatory to improve my EPC rating?

Making conservatory upgrades to improve EPC rating would not be worth the investment for most people. One possible situation where it could be beneficial is if:

  • Your integrated conservatory has single glazing
  • You are only a point or two off a higher band
  • There are no other obvious or cheaper ways to move up

Here it may be worth considering upgrading to double glazing, but it would be best to seek professional advice and ask your assessor whether it would be worth it. In most cases, it would not.

You can also ask an assessor to carry out an energy assessment without lodging the EPC to the EPC Register. This means you can get an estimate of the impact of your conservatory on the energy efficiency of your home without the actual certificate being made publicly available.