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How To Improve Epc Rating From E To C

Improve epc rating concept

Getting an E rated EPC to a C rating is not going to be a simple task. But with some expert advise I will show you how.

There are many articles on the web that supposedly give advice on how to do this.

Most of these articles are written by people who have little actual experience in using the EPC software and only state generic ways to improve energy performance and efficiency but give little knowledgeable useful advice that will truly reach the desired outcome of raising an EPC from an E to a C.

For example if an article tells you that low energy lights are going to make a big difference to a domestic EPC rating, then you may be disappointed.

So if you currently have an EPC rating of an E39 and you want to get to a C69 you are going to need an addition 30 points.

Take this quick quiz:


Low energy lights

Have a rough guess of how many points you will gain on your EPC rating going from no low energy lights in the property to 100%.low energy lights.

Let’s have another quick quiz to see how you do:

Double glazed windows

How many points do you think the EPC rating would improve by going from all single glazed windows to 100% double glazed windows?

The Author

My name is Rickie Dickson and as a qualified Elmhurst Energy Domestic Energy Assessor (DEA) and a qualified  On Construction Domestic Energy Assessor (OCDEA), I’ll give you practical useful advise on how to really improve your EPC rating with a few tips and tricks on the way.

Understanding The EPC rating scale


EPC rating on Govenment website

So, to get from the highest E rating band of 54 points to the lowest C band of 69 means you are going to need to improve it by 15 points.

In EPC terms 15 points is a lot and it’s going to mean doing multiple improvements on the EPC recommendation.

If your EPC rating is the lowest EPC rating of an E39, then you’re going to need to improve it by a massive 30 points.

First you need to understand a little about how the EPC rates a property.

After the Assessor enters all the data into the software, it runs a complicated set of calculations.


The 3 things that have the biggest impact on the EPC rating are

·       The amount of Insulation

·       The Heating System

·       The fuel source used to heat the home.

For a property to be rated an E, it probably means it’s rating poorly on 2 of these items.

The 3rd item on this list often surprises people.

Because the EPC rating is based on the cost to provide heating and hot water to a home, the cost that you pay for a particular fuel type plays an important role.

Below is an example showing the difference that the fuel source alone can make.

In this example, all elements of the house are the same, the only difference is the fuel used to heat the home.

Example property

1930’s solid wall semi detached property with a cavity extension, 100mm insulation in loft.

front of solid walled 1930s semi
Gas Boiler
High Heat Retention Storage Heaters
Bulk LPG
Peak rate Electric Heaters
Bottled LPG

So if your property is heated by one of the expensive fuel sources ie, Bulk LPG, Peak rate electric, or Bottled LPG then depending on the property type it is going to be extremely difficult, if at all possible, to reach an EPC rating of a C.

Get a new EPC Certificate 

You should first start by getting an up-to-date Energy Performance Certificate to get an accurate reflection of where the property currently stands. In many cases improvements may have already been made that are not on the previous EPC.

This will also give the Assessor the property data required for them to produce different scenarios that will show you the exact impact of any further proposed improvements.

Once you have the EPC there will be a section called “Improve This Property’s Energy Rating”

The example property below is currently an E53. Here is the list of improvements recommended on the EPC.

The recommendations will show you what the rating would be if you made improvements. However, these recommendations are showing the rating in a cumulative order, which means that you must have carried out the steps above to achieve the rating shown.


Energy recomendation list

Tip 1

How to get an idea of which improvements will get you to a C rating the easiest.

·       Have a look at the “Improve this property’s energy rating” section on the EPC

·       Look at the “typical yearly saving” line for each step

·       The higher the “typical yearly saving” figure, the higher will be the epc rating improvement.

So in our example above, the typical yearly saving for each improvement are:

Increase loft insulation to 270mm
Internal or external wall insulation
Floor insulation
Replace boiler with new condensing boiler
Solar water heating
Solar photovoltaic panels, 2.5 kWp
Estimated Saving

This clearly shows you that solar photovoltaic and internal or external wall insulation will have the biggest impact on significantly raising the property’s epc rating.

In reality, customer choice comes into it depending on cost and ease of implementing any particular improvement.

What the EPC can’t tell you is what the rating would be if you wanted to for instance carry out steps 2 and 4 only.

By far the simplest, most cost-effective route to achieving a C energy rating is to employ the services of your Assessor to produce a more detailed property-based report called a MEES report. 

Tip 2

Some things in your home actually lower your EPC rating

The EPC won’t tell you things in the property that actually lower the EPC rating. However, if you had a MEES report, your EPC assessor can give you further guidance.

Examples of items in a property that lower the EPC rating.

1.       Electric heating as secondary heating

These are quite common in gas heated homes and are often found in living rooms, but are rarely used. These lower your EPC rating by around 4 points. Consider removing it if not used.

2.       Open chimneys.

These lower your EPC rating by around 1 point per open chimney. Consider capping off the chimneys if not used or blocking the chimney with a chimney balloon.

3.       Decorative gas fire in an open chimney

If present in a property this will tank your EPC rating by around 8 points. Consider removing it if not frequently used and block off or cap chimney.

Another reason your EPC may be rating lower that perhaps it really is, is because of lack of evidence.

The assessor can only put information into the software if they have photographic or documentary evidence. Most of the photographic evidence will be gathered by the Assessor as they go around the property during the site visit.

In some cases, you will need to provide documentary evidence, this will normally be in cases where the insulation has been improved over what the property was built with, but it can’t be seen. The most common elements are

  • Flat roofs
  • Sloping Ceiling
  • Floor Insulation

If nothing can be provided, then the assessor has to use the worst case scenario and enter unknown. The software will then use what the property would have been built with depending on it’s age.

Remember: an Assessor can’t put information into the software just because you told him that’s what was you fitted.


The kind of evidence that would be acceptable is any of the following:

  • building plans
  • an invoice from the builder detailing what work was carried out
  • a schedule of work from the contractor detailing the proposed work matched with an invoice to prove the work was carried out.

The documentation must show the property it relates to along with the thickness of the material fitted.


Tip 3

Be specific about the insulation fitted

If you are providing documentary evidence of insulation fitted that can’t be seen, try to name the exact product fitted.

Here’s why:

If your documentation, for example, says 100mm insulation was fitted in the suspended floor, the software will add 100mm of insulation.

However different products have different thermal values, so for example the thermal conductivity of 100mm of mineral wool is around 0.044 which is significantly different to 100mm of an insulated PIR (foam) board, such as Kingspan, or Celotex or Xtratherm etc, which is around 0.022.

The lower the thermal conductivity the better the material is at reducing heat loss. So if we enter 100mm insulation then the EPC software will enter the worse thermal value for a 100mm insulation product.

It even gets worse. For example, if you fitted 140mm PIR board, there is only a limited range of thicknesses that can be entered into the EPC software. They are 50mm, 100mm and 150mm.

If the thickness of a product isn’t one of these 3 sizes, the Assessor has to enter the next thickness down. So in our previous example of you having fitted 140mm PIR board, this would have to be entered in as 100mm and as I previously mentioned this will also be using the worst thermal conductivity for a 100mm product.

So what’s the solution to the problem above?

If possible, in your documentary evidence get or use the exact name of the product fitted especially if it’s a PIR rigid foam board.

So instead of your builder just writing “fitted 100mm Celotex board” get it to actually name the type of board ie “fitted 100mm Celotex GA4000 board”.

There is a convention in the EPC rules that says if the Assessor can provide evidence that the product fitted has a thermal conductivity of 0.022 or less, then the thickness of the insulation thickness entered can be doubled.

Alternatively, you can get the u-values calculated by a suitably qualified person. However most Assessors don’t like to change any default u-values in the software as it triggers an automatic audit by the Accreditation body.

The Assessor will then have to provide evidence of the u-value calculation along with evidence of the qualification of the person that carried out the calculation.

As part of our MEES report, we are suitably qualified to provide calculated u-values where they will help to show a more accurate reflection of the property and hence a better EPC.

Loft conversions

If you have a loft conversion, then providing documentary evidence of when it was built is an important part of maintaining a good EPC rating.

This documentation is needed because in the room in the roof most of the insulation can’t be seen and in the absence of any documentation, the Assessor has to enter the year of the conversion as Unknown and the software will use the worst case scenario which is the age the main house was built, this will then use the default building regulations for that period.

The type of evidence you should provide could be any of the following:

  • A completion certificate from the local building control body
  • A copy of the building plans showing the date
  • A dated schedule of work from the contractor
  • Any other documentation that shows the date it was built. 

Get a custom MEES report

We always advise to get a custom MEES report if you are confused by which improvements you should be carrying out. Some advantages of having this report are:

  • Avoids you wasting money on the wrong improvements that won’t move the rating much.
  • Get different options and step by step instructions of what you need to do.
  • Identify things in the property that are making your rating lower than it should be.
  • Remove the guess work from the EPC rating. You will know the exact outcome of EPC rating before you carry out any upgrades
  • Will ultimately save you money


The cost of our MEES report is spilt into 3 stages

1.       The preliminary site visit to gather the data on the property: £69 . If the property is found to be a C rating at this stage, no further charges will apply and the EPC will be registered.

2.       To produce the actual MEES report: £90

3.       To revisit the property to gather evidence of the improvements made and to lodge the EPC: £69

Payment is required at each stage.

To order a MEES report either call us on 0800 046 7345 or fill in our contact form.



To get a property from an EPC E to C rating, here are the key points.

Get an updated EPC

Understand the 3 main things that affect the EPC the most are:

·       The amount of Insulation

·       The Heating System

·       The fuel source used to heat the home.

Provide documentary evidence of any insulation improvements that you have done that can’t be seen.

Get a qualified Assessor to produce a custom MEES report with alternative step by step instructions of what to do to reach your desired rating.


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