The government is committed to improving energy efficiency and reducing the carbon emissions of new homes and non-domestic buildings.
Energy efficiency requirements for new homes and non-domestic buildings are set by Part L (Conservation of Fuel and Power) and Part 6 of the Building Regulations 2010 (“the Building Regulations”).
This consultation set out the government's plans for achieving the Future Homes Standard and Future Buildings Standard. It set out technical proposals for changes to the Building Regulations, the associated Approved Document guidance and calculation methods.
You can see further details and the consultation questions on the consultation platform.
Webinar
A webinar on this consultation can be accessed through this link.
https://attendee.gotowebinar.com/recording/3386785422290368861
Below is a summary of the CIBSE response.
OVERALL COMMENTS FOR ALL BUILDINGS
- As in previous consultations, CIBSE would like to see a change from the reliance on notional buildings, as this does not set clear and trackable targets, and does not sufficiently drive the most efficient designs.
- As in previous consultations, CIBSE has concerns about the reliance on primary energy as a key metric. We acknowledge its usefulness in driving energy efficiency at the system level, but to some extent, variations in energy sources and system impacts are already taken into account by carbon as a metric. On balance, we think it would be more appropriate to use energy use (total delivered, from all sources including on-site renewables). This makes it easier to track and compare performance year-on-year, and for consumers to relate to.
- As in previous consultations, CIBSE supports the use of a fabric efficiency requirement in homes, but has concerns about the Fabric Energy Efficiency Standard as a metric, because it is theoretical, a moving target (set by the notional building), and not measurable. The rationale for not using Heat Transfer Coefficient or space heating demand is not explained in the consultation. As in previous consultations, CIBSE recommends a similar metric in non-domestic buildings, covering space heating and cooling.
- We note that embodied carbon is out of the scope of this consultation. CIBSE has supported Part Z since its inception, and we urge government to come forward with proposals as soon as possible.
NEW BUILD HOMES
- The proposals in terms of fabric efficiency and services (Options 1 and 2) do not represent a sufficient level of ambition to match the stated aim i.e. homes ready for Net Zero:
- The proposals are even less ambitious than in the previous consultation, despite 84% of respondents at the time recommending that these previous proposals were not demanding enough.
- The resulting space heating demand would be unlikely to meet that recommended by the Climate Change Committee.
- By DLUHC’s own assessment, Option 2 would result in higher energy bills than the Part L 2021 requirements i.e. a step backwards (!).
- The proposals correspond broadly to the 2 least ambitious “contender specifications”, out of 5 put forward by the Future Homes Hub. No justification is given why the 3 more ambitious options have not been taken into account.
- As a result, CIBSE expects to submit similar comments to those made in the previous FHS consultation, and especially recommending improvements on airtightness and ventilation e.g. notional dwelling to have similar levels of airtightness to Passivhaus, and MVHR (even if MVHR is not mandated, this would set a real best practice level). More ambitious airtightness levels would also support DLUHC’s aim of improving build quality.
- CIBSE strongly supports the clear statement that new build homes with a gas boiler (even a “hydrogen-ready” one) will not be able to comply.
- CIBSE strongly supports the aim to improve the commissioning of systems, both for new homes and for new systems in existing homes. However, as we did in the previous consultation, and as is the case, we do not think that guidance is sufficient. As previously, further measures should be considered, for example a penalty applied in the energy compliance calculations, unless evidence of commissioning is provided. Ensuring good commissioning would also benefit indoor air quality, and often acoustics in the case of ventilation systems.
- CIBSE supports the intent to improve handover procedures and information, including the Home User Guide.
- CIBSE strongly supports the increased attention to post-completion testing. However, we would like to see a commitment and timeline for turning these into firm requirements, so that build quality and performance become the norm.
- CIBSE agrees that incentives should be introduced to encourage post-completion testing before it is mandatory. On balance, CIBSE does not think that a government-endorsed brand is the best way to achieve this. Instead, CIBSE recommends reviewing the feasibility of creating a performance rating, which could be used by all homes (whether new or existing) based on post-completion testing results.
- Home Energy Model, with FHS wrapper: CIBSE strongly supports the use of local weather files, rather than a single location (East Pennines) currently used for all dwellings. However, we are concerned that the proposed application is far too limited: the local weather file would also be applied to the notional building i.e. applying a moving target rather than a consistent level of performance throughout England: as the consultation itself states, it will be possible to comply with the same fabric specifications regardless of location, the only change being the estimated heat pump sizing. This means that householders in the north will continue to risk being exposed to higher heat demand and energy bills than those in the south.
- We continue to support the application of Part O and its application to other residential uses. We have gathered suggestions for improvements to the methodology and wording of Part O, and we recommend that it should refer to the upcoming revision of CIBSE TM59 (including revised bedroom criteria).
HOMES CREATED BY MATERIAL CHANGE OF USE
- CIBSE strongly supports the proposal to increase requirements on homes created by material change of use (MCU). We have repeatedly asked for this in the past, highlighting the well-evidenced poor standards of these homes.
- We strongly support the proposed extension of Part O to homes created by change of use.
- CIBSE supports the proposal that airtightness testing would be required. We are reviewing the other proposals in more detail, to ensure that opportunities for a whole house retrofit are captured as part of the MCU.
NON-DOMESTIC BUILDINGS
- CIBSE supports the proposal that the Future Building Standard will apply to all new non-domestic buildings from 2025, rather than its implementation being phased.
- CIBSE supports the extension of regulated energy uses to include lifts and moving walkways, as fixed building services. Further uses which could become regulated include large commercial catering equipment, swimming pools and spas.
- CIBSE welcomes the acknowledgement that NCM tends to under-estimate space heating demand, and the statements that changes have been made to address this (section 13.4.1). Together with LETI, we made a contribution to the 2022 call for evidence, to highlight the need for changes. CIBSE does not think that the changes proposed are sufficient to address the concerns raised in response to the call for evidence. We recommend a substantial review of NCM, as was carried out for SAP a few years ago.
- As in previous consultations, CIBSE are concerned that the requirements for an ”energy forecast” for non-domestic buildings over 1,000m2 can be met by methods which are not intended nor suitable for it. This risks confusing designers and building owner, and adding work for little or no additional value. The requirement should be met by energy performance modelling (e.g. PHPP, NABERS, or other methods within the CIBSE TM54 modelling framework).
HEAT NETWORKS
CIBSE are concerned that the proposals are not sufficient to ensure that new build networks offer a low carbon solution compared on-site alternatives, nor that they will drive the decarbonisation of existing networks. This is due to a number of reasons including the setting of the notional building when connected to a heat network, and the calculation methodology for carbon content of heat from networks.
Our response on this topic should be read alongside that to the recent Heat Zoning consultation.