CM21 is around the national average for energy efficiency.
Looking at the energy data for CM21, this East Hertfordshire district scores an average of 68 out of 100, placing it around the national average. Compared to the national average of 67, that puts CM21 around the norm for England and Wales. The most common rating band is C, with 16.0% of homes rated A or B and 72.2% in the C or D bands. Meanwhile, 2% of homes sit in the F or G bands — the least efficient categories. In practical terms, a C rating suggests reasonably efficient homes, though there is still room for improvement on heating and insulation.
The area is characterised by houses. Flats make up a notable 25% of homes here. Around 72% of properties are owner-occupied , while 23% are privately rented . Gas central heating is the main fuel source for 81% of homes, which is typical for urban areas across England.
There is genuine room for improvement here. If every recommended upgrade were carried out, the average score could climb from 68 to 81 — a 13-point jump that would lift the typical rating to B. If you live in CM21 and want to reduce your energy bills, start with our guide to loft insulation — it is one of the most cost-effective upgrades you can make.
EPC Rating Distribution
Energy Efficiency Score
Potential score if all improvements made: 81 (rating B)
Recommended Improvements
Government funding may be available for some of these improvements. Check grants →
More data — property types, tenure & fuel
Property Types
Tenure
Main Fuel Types
Frequently asked questions
What is the average EPC rating in CM21?
Homes in CM21 have an average EPC rating of D, scoring 68 out of 100 for energy efficiency. That figure comes from 3,765 certificates issued across the district.
This is broadly in line with the national average of 67 — neither particularly efficient nor particularly wasteful. A D rating typically means higher-than-necessary heating bills, especially in older properties without adequate insulation.
What percentage of homes in CM21 are rated F or G?
2% of homes in CM21 fall into the F or G bands — the lowest energy efficiency ratings. Nationally, the figure is 2.9%.
This is actually better than the national picture, suggesting the housing stock in CM21 is in relatively good shape — though any home rated F or G would still benefit enormously from basic upgrades. Landlords should note that F and G rated properties cannot legally be rented out under current MEES rules.