Check your EPC 'Features' Table

At the time of writing the methodology for EPC assessments of existing dwellings is RDSAP 9.94. The much anticipated RDSAP 10 update has not happened yet and a significant methodology overhaul from RDSAP to the Hone Energy Model (HEM) is proposed for 2025.

On the journey to improving your EPC rating, a good place to start is to check if your property already has an EPC, either one that's currently still valid (they last for 10 years), or even perhaps one that has expired.

If you have an existing or previous EPC, locate and review the contents of the Features table. This can provide some useful headline information to work from.

Here is the Feature table from an old EPC for the house that I live in. This is a 1950s terraced house, and the EPC is rather out of date:

What you can do is check each of the features, consider whether they seem correct to you, and consider whether you might be able to improve the energy performance of that property feature.

You can also compare with the information on the EPCs of your neighbouring properties.

Remember, the Features table on an EPC is just a summary. There is much information that a Domestic Energy Assesor records during an assessment that is not indicated on the Features table. The Features table should therefore be considered with this in mind.

In the table above from my EPC, each Feature is listed once. For some properties however, it's possible that some of the Feaures might be listed multiple times.

This can occur if you have an original building which has then had extensions built at different later dates. It might be possible for the Walls and Roofs features to be listed twice or even three times, with different wall types and roof types declared for the different building parts.

Perhaps there might be a Sandstone wall for the original building, a solid brick wall for the first extension and a cavity wall for the second extension.

This can also happen if a building part is declared as having a section of 'Alternative Wall' where a mix of construction types have been used in one building part.

This section decribes the type of external wall of your property.

Part of the information expressed here might have been manually declared by an energy assessor during an assessment, and part might have been automatically determined by the EPC methdology (RDSAP) based on the date of construction. A measurement will also have been made of the thickness of the wall. Some of this information can be determined from how the Features Table describes your wall.

Here with my house, firstly the wall type has been manually declared as a Cavity Wall, which is correct. The assessor could not locate any visual evidence of retro-fitted Cavity Wall Insulation (CWI) so has correctly described the insulation status of the wall in the assessment as 'As Built' (ie still in the state that it was at the time of original construction). The EPC methodology has therefore referred to the building regulations in force at the time of construction (1950s in this case) and determined that the U values required for walls by building regs at that time was so poor (greater than 0.6) that it expects that there will not be any CWI in the wall - hence it says 'no insulation (assumed)'. This is actually correct for my external walls - there is no cavity wall insulation present.

With your property, does the entry for Wall appear to match your expectation of the wall type present in your property?

If not, do you think a mistake may have been made?

Is there a way you could improve the energy performance of your wall(s)?

With a standard pitched roof, you'd expect to see a level of measured loft insulation present - 50mm in my case (although there was actually much more than this in the lfot, and the assessor had clearly made a mistake here).

There's no mention of 'assumed' in brackets on my EPC here because access was available to the roof space for the assessor to check, and they manually declared a level of insulation that they had supposedly measured.

If access was not available to a pitched roof, perhaps in the case of the loft hatch being locked in place, then you might see: 'Pitched, no insulation (assumed)'.

This can also be the case if the area of loft was boarded over and the owner was not available to, or not prepared to lift the boards.

In the case of sloping ceilings and vaulted ceilings then access is clearly not available and 'assumed' will appear, with the insulation status depending on the build date of that building part.

A 'Room In Roof' (where rooms are present within the area of pitched roof space) is similar in that access is often not available, although the flat ceiling part can sometimes be accessed and measured.

Does the description on your EPC for Roofs match your expectation of what it should be?

Could you improve the energy performance of your roof?

Do not under any circumstances however install spray foam insulation between the rafters.

For me it's 'Fully Double Glazed', which matches what I have present in the building. Double Glazing can be categorsied in various ways but that level of detail is not shown in the Features Table.

Broadly speaking, glazing can be Single, Secondary, Double, Triple.

Does the description match what you have at the property?

Can you improve the energy performance of your Windows? Is it worth the expense doing so?

See our page about Glazing. Good improvements can be made moving away from Single Glazing but it might not be worth your while improving existing double glazing.

As per our note at the end of this page, always check with an energy assessor about your specific property before making decisions.

This describes the source of heat used to keep the living areas of the property warm. This is often referred to as 'Space Heating' in energy performance circles.

This is an important section, and it has a big effect on the EPC rating of a property. It needs to be considered in conjunction with the section for 'Hot Water Heating' and 'Secondary Heating'.

As a chid I remember tungsten filament bulbs and how hot they ran. We'd have to unscrew a blown bulb with a double-folded tea towel before fitting a new bulb, and the light fittings would brown over time becase of the long-term exposure to high levels of heat. Light fittings would be rated by to the maximum power of bulb they would accomodate, and some domestic bulbs were even rated at 150W. Imagine how much power would be drawn if you had 10 of them powered up at the same time.

Things have changed since then, and the sale of filament bulbs is now prevented by legislation. Even fluorescent tubes in the UK are on their way out. The move for some time has been towards what is called 'Low Energy Lighting', with LED of particular interest.

We have a page just about lighting, and it's worth reading to ensure you understand what counts as 'Low Energy Lighting' from an EPC perspective. Moving to 100% Low Energy Lighting doesn't make much of a difference to the EPC rating, perhaps 2 points for a typical house when moving from none to 100% but it all helps.

Does the percentage displayed on this Feature seem about right to you for your property? Usually, with an EPC that has just expired (they last 10 years), the percentage will now already be much greater that that indicated.

Could you increase the percentage of Low Energy Lighting in your property up to 100% if it's not already?

Here, there will be an indication of the type(s) of ground floor present in your property.

Common types might include Solid floor or Suspended Timber, or if it is a flat it might indicate 'Another property below'.

Does the floor type indicated here seem right for your property?

Would it be possible to add insulation to the floor to improve the EPC rating?

Would it be worth doing so? Probably not in most cases for such a small gain.

This is one of those less interesting looking items that I would often lump together in my mind along with Floor type and Heating Controls before I became an Energy Assessor.

Nowadays I know better, and it is really important to look at this particular Feature in the table.

The example of my EPC is particularly important, and I want you to check if you have this entry on your EPC Features table or not. On my EPC it says:

'Portable electric heaters (assumed)'

Normally, Secondary Heating is any form of additional fixed heating source such as a gas fire or log burner or electric heater etc that might be in the property in addition to the main heating system, assuming you have one.

In my property the main heating system declared at the time was storage heaters.

However, and this is the important part: during the assessment of this property, the energy assessor recorded that one or more habitable rooms was not heated by the main heating source (Storage heaters in this case).

The EPC methodology therefore assumes that, in the case where no other source of Secondary Heating was declared in the property, in order to fulfil the shortfall in heating required to maintain the internal temperature due to the un-heated habitable rooms to that required by the model, that portable electric heaters will be used by the occupants.

As a result, the EPC rating is reduced considerably due to the higher cost of peak rate electricity compared to that of the main heating system (cheaper overnight electric for the storage heaters in my case).

This effect is further amplified if the main heating system uses a far cheaper fuel such as a condensing gas boiler.

A similar degradation of EPC rating can also occur if you do indeed have one of more fixed peak rate electric heaters of some sort in the property, and a main heating system that operates on a cheaper fuel (including Heat Pumps).

See our Heating Systems page for more details and instructions to make sure your EPC rating is not affected like this. See also our Conservatories page if you have a conservatory, because that can be considered an un-heated habitable room in particular situations.

One useful approach is to compare the Features Table of your EPC against that of your neighbours properties.

Compare with properties of the same age and type. In particular, if the property is semi-detached or a terraced house you can compare with your directly attached neighbours.

There may be some differences with insulation added after original construction, but you might be able see what is achievable for your type of property.

It might also be possible to spot mistakes in an EPC by comparing in this way.

Always check with a Domestic Energy Assessor before deciding what changes to make to a property in order to improve your EPC rating.

Without doing this, you will just be making changes to your property from a position of uncertainty. When you instruct an asssessor to produce a new EPC you would not know whether the changes you have implemented were the bvest ones, whether they will have made a difference, or what magnitude of difference, until you get that new EPC, and you may have spent money unecessarily.

By instructing an Energy Assessor from the outset, and asking them specifically what you can do to improve your EPC rating, you will be working from a position of certainty, and be able to target the most cost effective changes for your property.

So, get an energy assessor to assess your property first and make some recomendations to you (which will be far better than just relying on any recomendations listed on the EPC), and then get that same energy assessor back to assess the property again once you've completed any works. This will clearly cost more, but it's likely to save you even more money by avoiding 'improvements' that would not make a useful difference.

Click here to return to our 'Improve Your EPC' main page, and see if there is another way you could improve your EPC rating.