Nearly 9.5 million energy efficient homes are projected to face flooding or subsidence risk by 2055, according to analysis that challenges assumptions about the relationship between EPC ratings and property security.
Property data firm TwentyCi found that homes with stronger EPC ratings appear more exposed to long-term environmental risks than less efficient stock – a finding with significant implications for landlords investing in green upgrades.
EPC B homes most exposed to subsidence
B-rated homes rank highest for subsidence risk, with 6.74% currently exposed. That figure is projected to reach 23.29% by 2055 – equivalent to approximately 7.4 million homes.
Flood risk follows a similar pattern. While G-rated homes have the highest current flood exposure at 5.65%, B-rated properties follow closely at 5.27%. By 2055, both figures are expected to rise, with B-rated homes reaching 6.52% exposure – more than two million properties.
Colin Bradshaw, chief executive of TwentyCi, said: “While energy performance certificate ratings remain a critical tool in assessing mortgage suitability, analysis of UK residential property data shows they do not reliably indicate exposure to key environmental risks such as flooding and ground instability.”
He added: “In fact, some of the UK’s most energy efficient homes are also among the most vulnerable to flooding and subsidence.”
This follows Residential Landlord’s coverage of the government’s EPC funding consultation, which explored how landlords might finance the upgrades required to meet 2030 efficiency standards.
Insurance and lending implications
The findings raise questions about how lenders and insurers assess property risk. Current mortgage affordability calculations often incorporate EPC ratings as a positive factor, but the TwentyCi analysis suggests this may create blind spots in portfolio risk assessment.
Bradshaw said: “For lenders, that creates a potential blind spot in portfolio risk. To build truly resilient mortgage books, lenders need to assess energy efficiency alongside a broader range of environmental risk factors.”
Across all EPC bands, homes rated A to C show higher exposure to flood risk than those rated D to G. Coastal erosion risk shows a different pattern, with G-rated homes most exposed at 0.09%, though the numbers are smaller overall.
The data suggests that newer, more energy efficient housing stock – often built on previously undeveloped land – may have been constructed in areas with greater climate vulnerability. The TwentyCi analysis draws on property-level data covering flood, subsidence and coastal erosion projections through 2055.
Opinion
Landlords facing pressure to upgrade properties to EPC C by 2030 may want to consider climate risk alongside energy efficiency. An investment in better insulation offers little protection if rising groundwater or shifting foundations threaten the asset itself. Due diligence now needs to extend beyond the EPC certificate.
