Almost every home in England and Wales has an Energy Performance Certificate on a public, free-to-search government register. Each one records the property’s energy rating from A to G, its floor area, its construction, and a list of recommended improvements. For any firm whose work makes buildings more efficient — insulation, glazing, heating, solar, full retrofit — that register is a map of exactly where the demand is.

Why EPC data is a lead source

A poor energy rating is a standing invitation to spend money. The owner of a band E or F house is paying more to heat it, is more exposed to energy prices, and — if they ever sell or let — will be marked down for it. The EPC even lists the specific measures that would improve the rating, with indicative costs and savings. It is, in effect, a pre-written scope of works the government published for you.

What an EPC actually tells you

Current rating (A–G) and the potential rating after improvements.
Total floor area — so you can size and price a job roughly before you ever visit.
Property type and age band — solid wall vs cavity, the era of construction, glazing type.
Recommended measures — loft and wall insulation, glazing, heating upgrades, controls — each with estimated cost and saving.
Assessment date — older certificates often pre-date any recent work, so the recommendations may still be open.

Floor area plus rating is enough to triage. A 180 m² band E detached house is a very different job — and a very different budget — from a 55 m² band D flat, and you can tell them apart before picking up the phone.

The D-and-below opportunity

The single most useful filter for retrofit work is rating. Roughly half of England’s housing stock sits at band D or below, and band D is the tipping point where meaningful, fundable improvement work starts to make sense. Filtering to D, E, F and G properties in your patch hands you a list of homes that demonstrably need what you sell. Layer on floor area or value and you can focus on the jobs that fit your firm — bigger homes for whole-house retrofit, specific eras for solid-wall insulation, and so on.

The rental angle: MEES

Landlords are a motivated sub-market because of the Minimum Energy Efficiency Standards. It is already unlawful to let most properties in England and Wales below an EPC band E, and the long-running policy direction is to push the minimum higher over the coming years. Any landlord with a band E (or worse) rental is a near-term buyer of improvement work, whether they’ve realised it yet or not. A property recorded as rented, sitting at the bottom of the scale, is one of the warmer leads in the dataset.

EPC + planning is the real signal

EPC data on its own tells you a property is inefficient. It doesn’t tell you the owner is ready to spend. The strongest signal comes from combining it with a fresh trigger. Two work especially well:

A recent planning application at a low-rated property means someone is already investing in the building — extensions and refurbishments are the natural moment to also tackle insulation, glazing and heating. You’re catching them mid-spend.
A recent sale of a low-rated home means new owners, who renovate far more in their first two years than at any other time. A band E house that just changed hands is prime.

How to approach it

Same discipline as any good outreach: be specific and useful, not scattergun. Reference what’s genuinely visible — “your property’s recorded as band E with solid walls, which usually means the biggest single win is internal or external wall insulation.” Lead with insight, not a price list. And respect data-protection norms: the EPC register is public, but that doesn’t make a homeowner a cold-call target — treat them like someone you’re offering genuine, relevant help.

The honest summary

The EPC register is an under-used, free, government-maintained map of every inefficient building in the country, complete with floor areas and a ready-made list of recommended works. On its own it tells you where the need is; combined with a planning application or a recent sale, it tells you where the need and the readiness to spend overlap. House of Planning Service attaches the EPC rating, floor area and an indicative property value to every planning lead, and lets you filter to exactly the ratings and values you want — so you can point your outreach at the houses that are genuinely worth a knock.

Using EPC data to find retrofit and renovation work