The Future Buildings Standard (Part L Changes)

The Ministry of Housing Communities and Local Government have carried out a consultation exercise on changes to both Part L (Conservation of Fuel and Power) and Part F (Ventilation) of the Building Regulations for non-domestic buildings in England.  The consultation aims to ensure that buildings can meet the UK’s legally binding target of net zero by 2050 and that the potential for buildings to overheat are minimised. 

Whilst there is expected to be an uplift to Parts L and F in 2021, it is by 2025 that the consultation aims to make the greatest impact on reducing carbon emissions and reducing overheating.

The below is a snapshot of some of the proposed changes to Part L.

Uplift to Part L (2021)

The consultation proposes that primary energy consumption be adopted as the new standard used to compare against the Notional Building with the current CO2 stipulation being used as a secondary metric.  In doing this, issues around the everchanging UK grid electricity carbon factor are removed.  New minimum standards for thermal elements, HVAC and lighting are proposed which would significantly raise the bar on current minimum standards which are currently achieved easily.  With grid electricity being less carbon intensive than gas, it is presumed that direct electric heating could become a cheap installation option in future, despite the unit costs of electricity being currently 4 times higher than gas.  The consultation aims to address this by ensuring that if electric heating is specified in the Actual Building, that a hybrid electric heat pump is then specified in the Notional Building, thus making it more difficult for the Actual Building to pass the assessment. 

The Government are keen to reduce ‘the performance gap’, where the in-use energy consumption is often significantly different than that estimated through compliance modelling.  The consultation proposes that energy forecasting is completed on those buildings with a floor area greater than 1,000m2 at the design stage.  This may involve the creation of complex energy models in a ‘Design for Performance’ style assessment.   In all, the Government intend that a 27% improvement in CO2 emissions from current standards are achieved from the Part L uplift.

Future Buildings Standard (2025)

The aim of the Future Buildings Standard is for new buildings to be constructed that are capable of becoming ‘carbon neutral’ over time as the grid electricity factor decreases and heat networks decarbonise.  This would mean that fossil fuel boilers would not be permitted by the Building Regulations.  This is a stance already currently taken by many local planning authorities. 

The likely makeup of heat sources will be through heat pumps, however the consultation does break buildings down into different types in the acknowledgement that certain buildings, warehouses for example, may require spot heating for which heat pumps would not be the most suitable technology.

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KJ Tait Engineers can assist with any aspect of Part L from general guidance to assisting in completing Part L calculations.