EXTERNAL ENVELOPE 49
The Warm Homes Plan – Building fabric in the age of high-tech homes
T
he Warm Homes Plan has arrived to replace the Energy Company Obligation (ECO). It represents a shift in focus away from a fabric fi rst approach to instead prioritise high-tech solutions such as PV, battery storage and heat pumps. This change in emphasis raises an important question: is abandoning the long-established principle that improving the building fabric is the best way to deliver energy-effi cient homes with improved thermal comfort and indoor air quality as well as low running costs really the right course of action?
Is addressing the building fabric fi rst a fundamentally good idea for energy effi ciency? The fabric fi rst strategy is founded on sound principles. Improving the thermal performance of the building fabric, including the walls, fl oor, roof, windows and doors, enhances the overall energy effi ciency of a home by: •
Reducing the rate of heat loss through the building envelope by using insulation effectively
• •
Carefully detailing junctions to minimise thermal bridging and associated heat loss
Reducing gaps in the building fabric to improve airtightness and prevent draughts and unwanted heat leakage
Whenever the fabric is enhanced, it is
important that an adequate ventilation strategy is also in place to remove stale air and moisture vapour to maintain good indoor air quality. The fabric fi rst measures reduce the demand placed on the heating system. As a result, it has to work less and consume less energy.
What part does building fabric play in the Warm Homes Plan? The £15bn government Warm Homes plan is designed to cut bills, tackle fuel poverty, create jobs and deliver energy security. Energy effi ciency is very hard to achieve without paying attention to the thermal performance of the building fabric. This is supported in the Warm Homes Plan document, where it states that, “Fabric insulation
measures, when installed with appropriate ventilation, remain a cornerstone
of energy effi ciency”.
Due to issues with the quality of solid wall insulation in the ECO scheme, there appears to be a reluctance to continue to support this under the Warm Homes Plan and cavity wall insulation barely gets a mention in the document. This seems strange as according to the Energy Saving Trust around 33% of heat can be lost through the walls of uninsulated homes.
What are the challenges faced when applying the fabric fi rst approach to existing buildings? The warm homes plan, ECO, is aimed at existing buildings. Existing homes can present challenges when it comes to upgrading the thermal performance of the building fabric: •
•
Houses may have been subject to home
It is important to carry out a thorough survey of an existing home in order to be able to evaluate and plan the most appropriate energy effi ciency measures taking a whole- house approach. This has been addressed by using a Publicly Available Standard 2035 (PAS 2035).
What benefi ts can a fabric fi rst bring that
cannot? • •
It can be diffi cult to know exactly what has been built with regards to the composition and construction of an existing home
improvement such as loft conversions or extensions that can change the thermal dynamics and ventilation of the original home design
• •
The quality of the work can be variable, and a record of plans and materials used may not be available
Measures such as thermal bridging can be harder to address as access may be limited and the exact existing design of existing junction details may be unclear
a technology-led
Upgrading the fabric fi rst can: •
approach
Increase homeowner’s thermal comfort by reducing draughts
Reduce the chances of condensation forming that can lead to mould growth
Help to limit the effects of overheating by use of insulation materials such STEICO’s wood fi bre boards
A technology led approach where PV, batteries and a heat pump is installed will give homeowners the benefi ts of access to cheap electricity and help to reduce carbon emissions. It may not be able to match the benefi ts that addressing the fabric fi rst can bring.
–
Both approaches bring different benefi ts together
they can work in harmony
to deliver high-tech homes that support thermal comfort, low energy use and lower energy bills.
01727 515120
www.steico.com/uk
ADF JUNE 2026
WWW.ARCHITECTSDATAFILE.CO.UK
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