The Government has announced a new consultation, which sets out its planned updates to Parts L and F of the Building Regulations and the proposals for a Future Homes Standard.
The consultation sets out government plans to set the domestic building industry on the path to zero carbon but there are serious omissions that threaten to slow the progress.
Part L 2020 Consultation
Building Systems Focus
The consultation outlines two options to uplift energy efficiency standards and requirements within Part L for domestic buildings: these include
- Option 1 is fabric focused; and
- Option 2 is low/zero carbon technology focused.
Option 2 is the preferred option for the government as 2020 is seen as a ‘stepping stone’ for the new Future Homes standard expected to come in to force in 2025 (see below). Option 2 is supposed to deliver greater carbon savings and lower fuel bills, but from our review of the document it does not seem to follow the successful lessons learnt from PassivHaus and adopting a fabric first design approach. This option would also introduce higher build costs for developers and higher dwelling prices.
Although the consultation acknowledges the issue of the performance gap between design and as-built performance, the proposals do not substantially address the issues. Greengage feel that we need a more robust and standardised way of monitoring the build quality (photographic evidence is proposed as part of the consultation) and the in-use energy performance (in a similar way to the NABERS energy rating system). These measures would not only help bridge the performance gap, but also address unregulated energy and help improve data around actual dwelling energy performance that would help strategic decision making around the energy performance of the built environment.
The changes proposed lack robustness around in-use energy performance and favour a potential over-reliance on building systems and renewables rather than encouraging high quality building fabric performance and climate resilient buildings. With a consultation on non-domestic buildings to follow in 2020, which will set out in-use energy performance ratings, there is a question why the same level quality assurance won’t be expected for our homes.
There is a distinct absence of new aspirations around innovative dwelling design, health and wellbeing, as-built performance and ambitions that employ successful standards developed in PassivHaus, WELL and the NABERS Rating. Dwelling design includes a new primary energy target, but this simplistic energy focused metric is likely to still result in well insulated dwelling envelopes that are at high risk of overheating, low levels of daylighting, insufficient ventilation and poor health and wellbeing for the occupants.
CIBSE TM59 design methodology for the assessment of overheating risk in homes, has been around for a few years and the GLA requires this overheating test for all major developments. Recent evidence has shown that overheating risk needs to be taken seriously in the residential sector. Many new or refurbished homes have designs that contribute to overheating risk by, for example, having high proportions of glazing (resulting in excessive solar heat gains), inadequate natural ventilation strategies or mechanical ventilation systems that are not delivering intended air change rates. Current Methodology expects compliance with the predicted weather file for the 2020s scenario. It is evident that this is no longer a future scenario as we are a couple of months away from 2020 and regulations should set 2030 or 2040 scenario as the minimum testing design year for climate change adaptation and resilient design.
There are several design considerations for daylighting provision that should be taken into account. These include window sizing, room layout/depth, internal finishes and positioning of exterior obstructions, such as other buildings or trees. These elements must be factored within the wider design objectives for a building, with energy efficiency being a key area to consider.
The Future Homes Standard
The Future Homes Standard Consultation presents a proposal from government to introduce a new Future Homes Standard. This builds on the Grand Challenge Buildings Mission to halve the energy use of new buildings by 2030.
The consultation proposes that the energy efficiency standards within new build homes need to be raised in order to ensure that new homes constructed now and in years to come will be future-proofed with low carbon heating, and ‘world-leading’ levels of energy efficiency. The government proposes that the Future Homes Standard will be implemented fully by 2025, with an intermediate uplift to energy efficiency standards in mid/late 2020.