EPC ratings are set to be overhauled, with four new metrics to measure energy performance: fabric performance, heating system, smart readiness, and energy cost, which will be introduced this year and become compulsory on 1st October 2029.

Rental properties in England and Wales will be expected to have an equivalent minimum EPC rating of C (rising from E), which will apply to tenancies from the 1st October 2030. It could be harder to achieve this rating equivalent under the new system.

New data, analysed by Emperor Paint, shows that over half (55%) of homes in England and Wales hold an energy rating of ‘D’ or below. This means that out of a total score of 100, homes have been rated as either:

D – Score of 55 to 68

A rating of D indicates that your home has average energy efficiency, but that there are still significant improvements that could be made to the property.

E – Score of 39 to 54

A rating of E means that a property has below-average energy efficiency, often found in homes that are poorly insulated and have outdated heating systems. Currently, this is the minimum energy efficiency threshold for rented properties.

F – Score of 21 to 38

An EPC rating of ‘F’ reflects a poorly performing home in terms of energy efficiency and is likely to have inefficient heating and little insulation.

G – Score of 1 to 20

An EPC rating of ‘G’ is the lowest rating and reflects a home with very poor energy efficiency. Homes that fall under this rating may have old single-glazing, very inefficient heating systems, and inadequate insulation.

Super hydrophobic masonry paint specialists, Emperor Paint, analysed the Department for Levelling Up, Housing and Communities dataset on the energy performance of domestic buildings in England and Wales, between January 2008 and February 2026.

Analysing 346 local authorities, Emperor Paint has ranked the areas which have the highest proportion of homes with an energy rating of ‘D’ or below:

1. Isles of Scilly: Taking the top spot is the Isles of Scilly, where 84.97% of homes have an energy rating of ‘D’ or below. This equates to 1,102 homes out of a total of 1,297.

2. Gwynedd: Ranking in second is Gwynedd, where 74.32% of homes hold an energy rating of ‘D’ or below. This equates to 42,721 homes out of a total of 57,483.

3. Pendle: Closely following in third is Pendle at 74.05%, with 35,686 homes out of a total of 48,193 rated as ‘D’ or below for their energy performance.

Local authorities across England and Wales with the highest proportion of homes with an energy performance certificate rating of ‘D’ or below
Ranking
Local Authority
Number of homes with an energy rating of A-G
Number of homes with an energy rating of D-G
Percentage of homes with an energy rating of ‘D’ or below
1
Isles of Scilly
1,297
1,102
84.97%
2
Gwynedd
57,483
42,721
74.32%
3
Pendle
48,193
35,686
74.05%
4
Ceredigion
38,511
28,100
72.97%
5
Castle Point
33,342
24,202
72.59%
6
Blackpool
93,109
67,072
72.04%
7
Barrow-In-Furness
28,415
20,459
72.00%
8
Hyndburn
41,318
29,432
71.23%
9
Eden
24,357
17,266
70.89%
10
Copeland
26,387
18,534
70.24%
11
Staffordshire Moorlands
40,316
28,204
69.96%
12
Richmondshire
21,391
14,906
69.68%
13
South Lakeland
45,696
31,819
69.63%
14
Burnley
52,733
36,704
69.60%
15
Denbighshire
48,923
34,013
69.52%
16
Isle of Anglesey
40,544
27,897
68.81%
17
Ryedale
24,667
16,957
68.74%
18
Southend-On-Sea
86,819
59,579
68.62%
19
Allerdale
40,351
27,681
68.60%
20
Carmarthenshire
87,899
60,062
68.33%
21
Conwy
62,193
42,399
68.17%
22
Powys
63,280
43,097
68.11%
23
Craven
22,775
15,468
67.92%
24
Bradford
279,800
187,403
66.98%
25
East Lindsey
80,881
54,065
66.85%
26
Scarborough
52,926
35,366
66.82%
27
Chiltern
26,010
17,311
66.56%
28
Calderdale
108,237
71,924
66.45%
29
Blaenau Gwent
30,166
19,902
65.97%
30
Pembrokeshire
59,844
39,206
65.51%
Commenting on the findings, Jack Reading from exterior paint specialists, Emperor Paint, said: “Changes to energy performance certificates mean that they will now be based on how properties retain heat, rather than how much energy a property uses. The new system, the Home Energy Model (HEM), will measure the following:

Smart readiness – Whether the property can generate its own energy (e.g., via solar panels).
Heating Systems – How efficient the heating system is (e.g., a heat pump would be considered to be an efficient heating system).
Fabric Performance – How well the property retains heat through insulation, draught-proofing and windows.
Energy cost – How much it costs to run the home each year (e.g., gas and electricity costs).
The vast majority of exterior walled surfaces are porous, meaning that they can become saturated with water. Research suggests damp content of 5% can lower the insulating properties of a surface by as much as 50%. This means that when the exterior walls of homes become saturated with water, it can lead to an increase in heat loss.

To improve the thermal performance of your home’s exterior walls, you will need to reduce the amount of heat your home loses as a result of wet exterior walls. Using super hydrophobic masonry paint can help you to achieve this as it reduces water absorption, while high breathability ensures no moisture can build up within the wall.

As weather conditions become more extreme, with warmer summers and wetter winters, exterior wall coatings not being included in EPC ratings, under ‘Fabric Performance’, represents a growing gap in how home energy efficiency is measured in the UK.

Without accounting for how walls perform in real, weather-exposed conditions, EPC scores risk overlooking a key factor influencing heat loss. As climate pressures intensify, this gap is only set to widen, meaning properties could appear more energy efficient on paper than they are in practice, an issue that is particularly significant given the UK’s ageing housing stock.”