Find out how the new AD L will impact your upcoming developments AD L White Paper

Part L: The three mandatory targets for all new build dwellings

24 Oct 2019


In this series of articles, we aim to answer some of your questions about the upcoming changes to Approved Documents L and F, SAP methodology and the Future Homes Standard.

Current proposals suggest these regulations will be coming into force in England from October 2020. Contact us with your own questions about the regulation changes, or to discuss our training seminars and workshops.


How is the new Part L being targeted?

The consultation version of the English AD L is proposing three mandatory targets for all new build dwellings.

One of the current targets – the emission rate – is staying but is being made much tougher to comply with. The other two – primary energy and affordability – are completely new.

Emission Rate

This sets a limit for the level of carbon emissions a new dwelling can produce.  The TER has been a requirement of Part L since SAP calculations became mandatory in 2006.

There are two big shifts going into this regulation change:

Firstly, the target is being significantly tightened. This could be by as much as 31% depending on the outcome of a Government consultation. If the full reduction carries through into final legislation this will be the biggest reduction ever made to the carbon emission target in a single change to building regulations.

Secondly, the new SAP methodology recognises the decarbonisation of the UK’s electricity grid which means electricity-fed heating systems will perform much better than they do currently.

Primary Energy Rate

This is calculated using the same technique as the Target Emission Rate, but instead of measuring Co2 , TPER is looking at energy use.

This approach also considers the energy required to produce the fuel, such as extracting gas, refining it, and pumping it through pipes to get to the dwelling. In this section electricity doesn’t perform very well, as we need far more energy to get a kilowatt of electricity to a house compared with a kilowatt of gas.

Household Affordability

The consultation paperwork doesn’t confirm how this will be targeted, but we expect a minimum EPC band will be set for new build. Homes which are fitted with heating systems that are expensive to run (such as panel heaters) may struggle to comply.

The challenge for developers is not only how to meet these three targets, but how to do it in a cost effective, technically viable way.

We have additional articles which explore the three targets in more detail, which you can find on our articles page.

View all articles