Decarbonisation Feature
An easy route to EPC improvements
Kevin Farrow at Recoup discusses how combining modulating electric showers with wastewater heat recovery can provide a simple, low-disruption route to improved EPC performance.
Decarbonisation 29
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t is now possible to improve a property’s EPC rating by installing a modulating Instantaneous Electric Shower (mIES) with a Waste Water Heat Recovery System (WWHRS). When retrofi tted to a ‘single bathroom’
property, this combination can improve an EPC score by up to three points; potentially providing an existing property with what it needs to achieve the EPC C goal with a simply applied showering solution. Greater improvements are achievable when using a higher-effi ciency vertical WWHRS unit installed with a pump or on the fl oor below the shower. Previously, the combination of electric showering and WWHRS was
not recognised within SAP or RdSAP, the methodologies used by energy assessors to calculate EPC ratings. However, the introduction of modulating instantaneous electric showers in 2024 enabled the safe and eff ective use of WWHRS technology with electric showers. Mira Showers and Recoup working with the Building Research Establishment
(BRE), together with the Department for Energy Security and Net Zero (DESNZ), have since assessed the modelling and performance of mIES used in conjunction with both horizontal and vertical WWHRS units for inclusion within the SAP Appendix Q database. As a result, the improvements from these technologies can now be recognised and accurately refl ected in EPC calculations for properties.
THE BENEFITS FOR EXISTING SOCIAL HOUSING For properties that already have an electric shower, upgrading to a modulating instantaneous electric shower is a straightforward like-for-like replacement. Where a mixer shower is installed, changing to an electric shower has the added benefi t of removing hot water demand for showering from the property’s primary water heating system, creating an electric powered, independent showering solution. Integrating a mIES with a WWHRS is also simple. T e cold water supply to
the electric shower is diverted through the WWHRS unit before entering the shower. When showering, heat energy is recovered from the shower wastewater that would otherwise go down the drain. Up to 90% of heat energy generated for showering is usually lost. T e WWHRS uses the recovered heat energy to preheat cold water that is sent to the shower reducing the energy needed to reach the desired showering temperature. T e mIES automatically reduces the electrical power it uses, improving effi ciency and saving up to 40% of the energy per shower use. A key advantage is the ease of installation. WWHRS systems can be
retrofi tted beneath a bath or integrated within a shower tray, making them suitable for a wide range of existing housing stock. Installation can oſt en be completed as part of planned bathroom refurbishment programmes, avoiding
Housing Management & Maintenance Autumn 2026
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