An architect-designed retrofit on the Coombe House Estate that reached the very top of the energy scale, the hard way: by transforming a 1950s house.
What tends to be true about homes with a top EPC rating is: they are nearly always new builds, run up by a developer to a specification sheet. A perfect score on an existing house is a different matter entirely. This one started life in the early 1950s with an EPC rating of E, in the bottom 14% of English homes for efficiency. The detached house we have just listed on The Fairway, within the private Coombe House Estate in New Malden, now holds a rating of 108 out of 108.
To put that in context, our own analysis of EPC lodgement data across England and Wales found that A-rated homes have made up an average of just 0.5% of all assessments over the last 15 years. The figure is creeping up, but it is still rare air. And a perfect score? That's rarer still.
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What it feels like to live here
This is one of a kind, even by the standards of Coombe House Estate. One of a kind, even by the standards of Coombe House Estate. Air moves cleanly through every room, filtered of dust and pollen before it arrives. The morning light gathers on the sun patio between two garden rooms. Vaulted ceilings lift the eye, Swedish oak grounds the step, and the kitchen anchors the whole composition. Out beyond the living space, the terrace runs down to a landscaped garden, granite underfoot, bespoke lighting picking out the planting after dark.
Designed to score top marks
Most of the talk around energy efficiency is about retrofit: the cost of fitting a heat pump or opening up walls to insulate. For most homes that means inching up a band or two. This one went all the way. The house was stripped back to its four external walls and rebuilt from there, with a two-storey rear extension, a new engineered-timber roof and insulation packed through the structure.
The result pays its way. Thirty-three solar panels and battery storage generate a surplus that earns income back through export tariffs, while the ventilation cuts heat loss by 95% in winter. None of it comes at the cost of character: across 3,062 square feet there is room for open-plan living and two garden rooms given over to a gym and a home office. The performance is the point, but it is not the first thing you notice.
What sits behind the perfect score
• EPC rating of 108 out of 108, one of the highest in the country
• Deep retrofit of a 1950s house, taking the EPC rating to the top of the scale
• Architect-designed, four-bedroom detached home, 3,062 sq ft, freehold
• Solar array with battery storage, generating surplus power and export-tariff income
• Air-source heat pump and MVHR system cutting heat loss by 95% in winter
• Open-plan living with vaulted ceilings, an acoustic statement panel and Swedish oak floors
• South-west facing terrace flowing to a landscaped garden with granite paths and bespoke lighting
• Morning sun patio set between two custom garden rooms, a gym and an office
• Custom kitchen with a full complement of Miele appliances
• Within the highly regarded private Coombe House Estate
How rare is a perfect score, really?
The trend is moving in the right direction, but slowly. A-rated homes made up 0.1% of all lodgements between 2010 and 2014, 0.3% by 2019, and 0.8% by 2023. It took until 2024 to clear 1% for the first time, at 1.7%, then 2.7% in 2025. Meanwhile a C rating is still the most common result, at 48% of all 2025 lodgements. So while more homes are climbing the scale, the very top remains almost empty, which is exactly what puts this listing in a league of its own.
James Stevenson, Managing Director of Sales at Foxtons, on what is changing at viewings:
"From our perspective on the ground, energy efficiency is becoming a far more regular part of the conversation during viewings and negotiations, particularly as buyers weigh up the long-term cost of running a home."
"What makes this one especially interesting is that it delivers that level of performance without compromising on the design or the quality of the living space. It sets a benchmark for what happens when design, technology and sustainability are fully aligned."
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A quick note on New Malden
New Malden sits in KT3, on the southwestern edge of London, with quick rail links from New Malden station and easy reach of Kingston and Wimbledon for shopping and eating out. The area is best known for having one of the strongest Korean food scenes in the country, everything from classic fried chicken at Chick and Beers to traditional shaved-ice dessert at Bingsoo, alongside leafy residential roads and strong schools. The private Coombe House Estate is among its most exclusive addresses.
See inside a home with a perfect EPC → Explore more New Malden homes →
Source: This article draws on Foxtons own analysis of EPC lodgement data for England and Wales (Gov.UK live tables on Energy Performance of Building Certificates, 2010–2025) and first-hand detail from Foxtons sales and marketing teams. If you have any questions, email us to ask a Foxtons expert
