Industry leaders in the Waste Water Heat Recovery (WWHR) sector have stated that the Future Homes Standard is missing opportunities to utilise Waste Water Heat Recovery Systems (WWHRS)
As the Future Homes Standard (FHS) moves into its final policy stage before being fully implemented, Showersave and Recoup have identified that the framework may limit opportunities for reducing domestic hot water (DHW) demand.
Hot water demand could rise by 50%
A SEA paper for Part L 2013 highlights the importance of improving hot water efficiency in homes, noting that domestic hot water accounts for around 35% of household energy demand, compared with 58% for space heating.
With the implementation of the Future Homes Standard, space heating may fall to 41% of demand, allowing hot water demand to rise to 50%.
Waste Water Heat Recovery Systems improve energy efficiency and lower costs
Waste Water Heat Recovery Systems (WWHRS) have been widely adopted across new-build specifications, and since 2024, more than 160,000 homes have been fitted with WWHRS, improving energy efficiency and lowering costs.
However, Showersave and Recoup now say that the WWHR sector has been ‘deprioritised,’ as SAP 10.3 (the UK’s transitional Standard Assessment Procedure, which ensures compliance with the FHS sap-10-3-full-specification-2026-01-13) suggests that similar levels of FHS compliance can be achieved without installing WWHRS.
They also say that more priority should be given to WWHR, as its impact can be greater than that of other demand-reduction systems, such as Solar Panels. Solar panels produce most of their output during the summer months when energy demand is lower, while WWHR is effective during the winter months when hot water demand is at its highest.
“A mismatch between when energy is generated and when it is needed”
Tony Gordon, managing director at Showersave, said: “One of the strengths of previous standards was that developers had flexibility in how they achieved compliance. If one measure wasn’t suitable for a particular site or design, it could often be balanced by others. While that flexibility still exists in principle, in practice compliance is becoming increasingly concentrated around heat pumps and solar PV systems, which risks stagnating the range of viable design approaches available to developers and specification teams, while limiting innovation.
“The concern is that this creates a more uniform approach to building performance, where domestic hot water – despite being the major energy demand in highly efficient homes – is not given sufficient weight within the compliance methodology. Relying heavily on annualised solar PV performance also risks a mismatch between when energy is generated and when it is needed, with implications for both running costs and system resilience.
“WWHRS are proven, widely deployed and deliver consistent savings regardless of season, offering a straightforward way to reduce energy demand within new homes. This is about ensuring developers, consultants and M&E specifiers retain a broad and practical range of options to deliver homes that perform as intended, both in carbon terms and in real-world energy use.”
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