It’s Official: Mixergy’s smart hot water tank can now enhance EPC ratings

September 28, 2021

Following a detailed assessment by the Buildings Research Establishment (BRE), our smart hot water tank is now featured in the exclusive Appendix Q product database.

This allows designers and landlords to factor additional carbon savings into the Standard Assessment Procedure (SAP1), upon which Environmental Performance Certificates (EPCs) and Dwelling Emission rates are based.

Our smart hot water tank only heats what is needed, unlike a conventional cylinder which heats the whole contents. This minimises the primary carbon used to generate a dwelling’s hot water, while maximising the availability of cold water for storing renewably generated energy; from Solar PV, for example.

This uniquely stratified method of heating water is now factored into the SAP Appendix Q database, allowing social landlords (under RdSAP) and new developers (under SAP 2012 and SAP 10) to recognise the full benefit of using Mixergy in their projects; whether new build or retrofit.

Not only will the user experience be enhanced by the smartest cylinder on the market, but asset managers and developers can also benefit from more energy-efficient SAP-certified properties.

In short, developers or homeowners that choose to install a Mixergy tank will now be able to accurately calculate and report its effect on the energy efficiency of a heating and hot water system – and include that information in the dwelling’s overall EPC rating.

For simplistic systems using a standalone Mixergy cylinder, the SAP assessor can now factor a partial state of charge, rather than standing heat losses at 100% of the heated volume. While this offers a modest carbon saving itself, the maximum benefit is achieved when the dwelling uses a Mixergy solar PV embedded cylinder. This product variant allows maximum local storage of solar PV in the cylinder, offsetting a considerable amount of primary carbon.

Depending on factors such as property age, size, and construction – and cylinder heat source (direct or indirect) – installing a Mixergy tank can reduce hot water bills by £160 per year (e.g. based on a 3-bed semi, using direct electric with 4kWp solar array), and lower carbon by >135kg/CO2/annum (e.g. in a 3-bed semi, using indirect with 4kWp solar array).

David White, Business Development Director here at Mixergy, explains: “Official recognition, within the SAP process, of Mixergy’s lower running costs and carbon footprint, is a significant step-change. This special listing allows house designers and developers to take full advantage of Mixergy’s adaptive ‘top up’ heating methodology in their calculations. More specifically: for developers, this means they can offer a better hot water product to their customers, while also demonstrating the carbon savings in their properties’ EPCs; while for social landlords the investment in a Mixergy cylinder not only addresses fuel poverty and the low carbon transition, but can now contribute to their RdSAP calculations – clearly demonstrating the financial benefits of Mixergy.’’

Our Mixergy tank can be tailored and purchased via a wide range of channels, including national distributors City Plumbing, Midsummer Energy, Bublshop, and more. It has already been successfully deployed across the UK by leading developers such as Cala Homes (Queenswood, Cammo Meadows); Sero Homes (Parc Eirin); and Ocean Housing (East Devon Council).

“Inclusion on Appendix Q is a real milestone for Mixergy,” concludes Martin Allman, Chief Commercial Officer. “It will make the Mixergy tank much more appealing to developers and installers, as they will be able to include it in their SAP calculations – potentially improving EPC ratings and helping them meet new government targets. That’s good for us, great for homeowners, and even better for the planet.”