The government recently consulted on updates to the Decent Homes Standard (DHS) and Minimum Energy Efficiency Standards (MEES). It came shortly after the consultation on reforms to Energy Performance Certificates (EPCs).
The DHS has not been updated for two decades, and CIBSE supports the general direction – that is, upgrading standards and aligning expectations in the social and private rented sectors.
The social rented sector would now be subject to MEES, a marked improvement on the current requirement for social rented properties to achieve a minimum EPC rating of F, which is wholly inadequate to reduce fuel poverty and provide healthy and comfortable homes. Equally, the private rented sector would now be subject to the DHS, a useful change considering that while 10% of social rented properties failed to meet the DHS in 2023, 21% of private rented homes did.
Reform to the EPC system acknowledged that a wider range of metrics may be needed depending on the policy objectives for which EPCs are used. CIBSE agrees that, in the context of the DHS, the fabric criterion should be used, to reduce fuel poverty risk and improve winter comfort. However, as pointed out in our response to the EPC consultation1, the proposed Fabric Energy Efficiency Standard is highly theoretical and not measurable. Alternative metrics should be used. As pointed out by the National Retrofit Hub2, MEES could better deliver health, fuel poverty and comfort outcomes, with more ambition and monitoring of these.
The DHS proposes new damp and mould requirements, which CIBSE supports in principle. Currently, however, these would rely on the Housing Health and Safety Rating System (HHSRS), which has not been updated for two decades. We recommend a review, and liaising with the UK Centre for Moisture in Buildings to consider the latest evidence and risk-assessment techniques.
CIBSE also recommends more attention be given to air quality and ventilation. Rather than just requiring that mechanical ventilation systems be kept in a good state of repair, this should be expanded to all ventilation systems, such as local extract fans – and they should require a good state of operation. Overall, the standard should require the provision of adequate ventilation and not only apply to systems that are already present.
More attention should also be placed on standards in electrical systems, which have evolved significantly since the last DHS update.
The DHS consultation proposes the introduction of requirements for window safety. CIBSE supports this, but restrictors need to be well thought through or they will excessively restrict airflow and increase overheating risk. With good design there is an opportunity to improve ventilation and/or reduce overheating risk. For example, window safety design can allow for secure openings at night for ventilation and provide shading in the day.
Finally, the reliance of the DHS on the HHSRS to limit overheating risk should be reconsidered. The HHSRS is mainly applied once a problem is identified, rather than being a proactive design standard. The DHS should encourage prevention and mitigation measures, especially passive approaches, which provide resilience and do not create a risk of increased energy costs and fuel poverty. This is particularly important because overheating is more prevalent in households living in social housing, on low incomes, or with members aged over state pension age3.
Ongoing and upcoming consultations
Consultations that CIBSE intends to hold are at www.cibse.org/consultations. These include the Heat Networks Technical Assurance Scheme – a crucial part of delivering heat decarbonisation and consumer protection, including energy costs and service levels. The consultation is not yet open, but is expected in 2025. A number of overview documents are already available bit.ly/CJJA25CPD5.
About the author:
Dr Julie Godefroy is CIBSE’s head of net zero
References:
1 CIBSE response to reforms to the Energy Performance of Buildings regime consultation, bit.ly/CJEPBRres
2 Minimum Energy Efficiency Standards: Delivering for tenants, National Retrofit Hub, bit.ly/CJNRHMEES
3 Lomas et al; Dwelling and household characteristics’ influence on reported and measured summertime overheating, 2021