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

SAP 10.2 walks into a bar… nobody looks up

04 Oct 2021


Designers of new build homes are continuing to proceed with caution whilst we await news of major changes to energy efficiency targets in England and Wales.

One of these updated policies will be a new version of SAP – the calculation method used to work out building emission rates, typical fuel costs and Energy Performance Certificate ratings.

So, when the latest version of SAP (10.2) was published at the end of August, why didn’t we get excited?


SAP versions

Since Approved Document AD L was last updated in 2014, assessors have been using SAP2012 to calculate the energy use of domestic buildings. Many in the industry agree this methodology is in desperate need of a refresh, and that is finally happening with SAP10. (Note the numbers after SAP are changing from year (2012) to version (10).

The problem with SAP updates is they’re redundant without an accompanying update to Building Regulations to enshrine their use in law. So although the first version of SAP10 was published in 2018, it still isn’t being used for measuring compliance. This isn’t a unique situation; SAP2016 was published and scrapped soon-after, because plans to update Part L were abandoned.

At the end of 2019, when the Government finally released a public consultation into revising Approved Document AD L, SAP10.1 was released. Many in the industry have been using this beta calculator to predict how homes built to today’s standards will fare against the incoming changes.

But this isn’t the definitive method. When the new AD L goes live, it will adopt SAP10.3 (which will be published closer to the go-live date).

We now have the missing link between 10.1 and 10.3… SAP10.2 was released without fanfare at the end of August. This updated version should give housebuilders a near-complete understanding of how their specification will work against the incoming AD L targets.

But it’s not quite gone to plan… SAP10.2 has two big omissions.

This is because there are two other Government consultations working through the Westminster pipeline. The Future Buildings Standard is one (search Energist articles for more details), and another is looking at ways of more accurately measuring the energy used and generated by District Heat Networks.

Both could shape the maths that SAP relies on, but despite both consultations closing earlier this year, the Government hasn’t issued responses to either.

This means SAP, and its authors at the Building Research Establishment, are in a state of limbo. They can’t release calculations that go against Government policy, but at the same time they don’t know what those policies are.


So SAP10.2 has been published as a halfway house… A SAP10.1 ½ if you prefer.

It does have a few updates, tweaks and clarities when compared to SAP10.1, but there’s very little difference in terms of the end results. On one side, this means developers who have invested in SAP10.1 analysis can be reassured that their reports are still giving valid results.

But it also means we’re no clearer on what the final regulations and targets are going to look like. And as we’re expecting these new regulations to go live in the first half of 2022, the Government is very short on time to tie up these loose ends.

If you are interested in discovering how your current specification will perform against the proposed regulation changes using SAP10.1 predictions, get in touch via the contact page.

View all articles


Jon Ponting

Energy & Sustainability Specialist


Jon Ponting

Energy & Sustainability Specialist
View all articles

Related Services

New build residential home development

SAP Calculation

Learn More

SAP 10 Analysis

Learn More