Blog Post 1

Why is my EPC rating so low?

There are numerous reasons for a low EPC rating and not all of them are obvious. Here I will untangle some of the more common reasons.

An Energy Assessor’s visit consists of a non-invasive visual check of the building. Basically, we are not going to lift up floor boards or pull down walls to see how your property is insulated. All our checks are done by what is either visible or what is documented on completion certificates for building work (for a roof room conversion, for example). We will gather our evidence, tap on walls, check for underfloor heating, examine the bricks, look at the loft, the boiler and meters. As Energy Assessors, we need to be able to document via photographs all the aspects mentioned above. If we are unable to see it, we are unable to document it.


An EPC is based on the evidence gathered and, without evidence, the worst case scenario is assumed by default. This is totally out of the assessor’s control and, without evidence, there is nothing that can be done to change this.

An EPC is evidence based. Without evidence the worst case scenario is assumed by default.

But my previous EPC had a higher rating! So the new one must therefore be wrong?
Not necessarily, no. The criteria has changed dramatically over the past few years, even if the thermal values of your property have not. Some of these changes can have a significant effect on the rating. EPCs have become more stringent and are taking a lot more of the property into account, such as party walls and roof room age.


My house is a new build but the rating is not A?
An EPC takes the age of the building into account and this alone has a huge impact on the rating. Generally speaking, the newer the property the better the insulation. It is certainly fair to say that newly built properties are the best insulated. However, it is very hard to achieve an A rating and would certainly involve some sort of renewable energy such as solar panels, etc. In fact, in all the thousands of EPCs we have done over the years we have yet to see one with an A rating!


Along with the building age there are numerous other areas to consider that could affect the final rating, such as the size of the property (the bigger the property the more area there is to heat). The detachment is another consideration, as if the building is completely detached it is loosing heat from all of the walls (even though they will be insulated, they will still loose heat). How the property is heated could also have a substantially negative effect on the rating, specially if it is located in an area of no gas supply.


Quick Facts

  • A rating of D60 is the national standard for a domestic EPC rating
  • EPC’s were introduced in England and Wales on 1st August 2007
  • Listed buildings do not require an EPC
  • Newly built properties must have a full SAP assessment before they can have an EPC
  • You cannot rent a property with an EPC rating lower than E
  • You can check if your property already has an EPC by visiting the EPC register