How each metric is calculated
EPC Lodgement Rate
Properties with a registered EPC ÷ Group stock
Indicates what share of the total portfolio has a lodged EPC. A low rate means a significant portion of stock is uncharted - its energy performance is unknown.
D-G Share of Lodged Stock
D-G properties ÷ Total lodged properties
Shows the proportion of lodged properties rated below EPC band C. A higher share means a greater non-compliance burden relative to the visible portfolio.
D-G to A-C Conversion Rate
D-G homes with confirmed A-C potential ÷ All D-G homes
Measures how much of the D-G stock can realistically reach band C with recommended measures. A higher rate means more of the problem is solvable through standard retrofit.
Total D-G Properties
Absolute count of D-G-rated lodged properties
The raw number of non-compliant homes in the portfolio. Reflects the overall volume of work needed regardless of portfolio size.
Stranded Homes
D-G properties − those with A-C potential
Homes that cannot reach band C even with all EPC-recommended measures applied. These require specialist intervention beyond standard retrofit programmes.
Stranded % of Group Stock
Stranded homes ÷ Group stock
Normalises stranded asset exposure across portfolios of different sizes. A higher percentage signals a greater share of genuinely hard-to-treat stock in the overall portfolio.
£ / D-G Home
Midpoint D-G indicative cost ÷ D-G property count
The average EPC indicative upgrade cost per non-compliant property. Useful for cross-HA benchmarking - higher values suggest more complex or expensive stock to retrofit.
£ / Upgradeable Home
Midpoint D-G→A-C indicative cost ÷ upgradeable property count
The average EPC indicative cost per home that has a confirmed route to band C. Reflects the unit economics of the deliverable retrofit programme for each HA.
Retrofit Readiness Index
(Conversion rate ÷ group max) ÷ (Cost per upgradeable ÷ group max) × 100
A composite score combining how much D-G stock is upgradeable with how affordable the upgrades are. A higher score means the HA is better placed to deliver a large retrofit programme quickly and cost-effectively. Scores are relative - peer comparison within this group only.
Key caveats
Group stock figures cover England and Wales only. Properties held by these organisations outside England and Wales are excluded from the group stock totals used in this analysis.
All cost figures are EPC register indicative estimates - modelled values from EPC certificates, not contractor quotes or feasibility surveys. Actual programme costs will differ.
The Readiness Index is a relative ranking only. It compares these 10 HAs against each other and would shift if additional organisations were included.
Sanctuary (61.8%), Riverside Group (80.0%), and Southern Housing (75.5%) have lodgement rates below 85%. Their D-G figures are likely undercounts - unlodged stock disproportionately skews towards poorer-performing properties.
RAG bands use true tertiles - the data determines thresholds, so exactly 3-4 HAs fall in each colour band per column.