REGULATION | FUTURE HOMES AND BUILDINGS STANDARDS THE FUTURE STARTS HERE Government net zero proposals for the Future Homes and Buildings Standards gave CIBSE Members plenty to digest over the Christmas period. Alex Smith looks at the proposed changes and how they will affect the specifying of low carbon technologies T he publication of the Future Homes and Buildings Standards (FHBS) consultation last month was intended to put the UK firmly on the path to net zero carbon. Due to come into force in 2025, the standard sets performance requirements to ensure new homes and non-domestic buildings are zero carbon ready so that no further work is required when the electricity Grid is decarbonised. This rules out fossil fuel heating, including hybrid and hydrogen-ready boilers. One thing the standard will not do is change the minimum building fabric standards. The government has said that the 2021 uplift in standards in Approved Document Part L, which have applied since June 2022, were intended to meet the specifications in the FHBS. However, improvements are proposed to the minimum standards for fixed building services and onsite electricity generation. There are also plans to improve guidance and minimum standards for heat losses from building services that directly support the installation of zero carbon ready technologies. The government expects low carbon heat networks to be a key route to compliance. New buildings can be connected to existing heat networks, but they must meet the performance requirements laid out in the FHBS. This means they must use heat supplied by low carbon networks or low carbon extensions to existing networks that may be powered by gas boilers. The heat network notional building has similar options to above, but a 4th-generation heat network is assumed, with primary losses of 12% and a seasonal coefficient of performance (SCOP) for plant of 3.0. For non-domestic buildings, the proposals base notional buildings on two sets of proposals: one for top-lit spaces in buildings and one for side-lit spaces. A heat pump is proposed for side-lit spaces and radiant electric heating in top-lit spaces. Enhanced efficacy of lighting and heat-recovery efficiency is also proposed. Like the proposal for homes, there are two options for non-domestic buildings, one with roughly double the amount of PVs for both side-lit and top-lit spaces. The government recommends option one, with higher levels of PVs. The consultation proposes the same fabric requirements as the 2021 standards, with the exception of warehouses and sports halls, which would have higher levels of airtightness to support the installation of low carbon heating. The standard will apply to homes and non-domestic buildings from 2025 New performance requirements New notional buildings are proposed to set the standard for homes, non-domestic buildings and heat networks. Notional buildings are benchmark specifications that meet performance standards, and they can be used by engineers and architects to model the performance of their designs, to gauge whether they meet the requirements. Two domestic notional building options are proposed. Option 1 maximises carbon savings and reduces energy bills, but has higher upfront costs for the developer because it features more low carbon technologies, including PV panels, decentralised mechanical extract ventilation, and wastewater recovery. Airtightness is also higher than Option 2, at 4 rather than 5m3 .h-1.m-2 @ 50Pa. For blocks of flats of more than 15 storeys, solar panels will be removed. For single-storey dwellings, wastewater heat recovery systems will be removed, as horizontal systems are more expensive and less efficient than vertical ones. 26 January 2024 www.cibsejournal.com CIBSE Jan 24 pp26-27 Future homes standard.indd 26 21/12/2023 17:53