The implications of axing Zero Carbon Homes in 2016


So, the government have at best ‘postponed’ the introduction of zero carbon new homes, leaving them under a potentially indefinite review. What are the implications and what does this mean for house building?

No Improvement

First off, there will now not be any improvement to the energy conservation provisions of the building regulations in 2016 (and presumably there won’t be any changes until at least 2019). Housebuilders will avoid the additional costs associated with building to these new standards (and house occupiers will have higher operational fuel costs than they would have had – but presumably also will not get the higher upfront costs passed on).

The additional costs of achieving the on-site requirements were not however potentially all that high, when compared to the potential benefit and savings for the eventual occupiers. The cost of the allowable solutions might have been more of a burden however.

The typical extra costs to achieve a 19% energy efficiency  improvement over usual industry practice (L1A 2013) for a medium scheme size, were published last year in the revised Impact statement for the Housing Standards Review . The additional costs were hardly excessive compared to the benefits e.g. £1,315 for a fabric lead 4-bed detached.

More demand for fuel and more CO2

There will now be more demand for fuel than there otherwise would have been if the 2016 standards were to have been introduced; this means that carbon emissions will be higher and that without the reduction in demand, we will need to generate and produce more.

The proposals for 2016 for domestic new build had already been much reduced in aspiration, to a 19% improvement on L1A 2013 levels on-site, compared to what the Zero Carbon Hub had proposed was cost effective and acheivable.

It was also considered likely that the Target Fabric Energy efficiency (TFEE) would have its 15% relaxation omitted, ensuring that a building’s fabric should meet a good initial standard to build towards the 19% target. Currently for most new homes, the TFEE is achieved fairly easily. Reducing the heating demand reduces the operational costs of living in a home as well as its associated carbon emissions, so a more stringent TFEE would have resulted in better insulated, more energy efficient places to live.

Allowable Solutions

The Allowable Solutions requirement was going to add additional costs to the housebuilder, but this was  going to be available to be used for a variety of carbon offsetting measures, which might have included helping to improve the energy efficiency of existing buildings, off-site renewables generation, community renewable energy projects etc. With this dropped, the potential for how it might have been used is also lost.

SAP (Standardised Assessment Procedure)

Alongside the 2016 Part L changes, the national calculation methodology for dwellings, SAP (Standardised Assessment Procedure) was supposed to be being updated to a new SAP 2015 version and DECC had already started initial work on this. There was already however an indication that the government were not minded to make any changes to non-domestic standards in 2016. Whilst this had been left as an option in previous statements, there had been no official consultation or discussions and it was looking unlikely, despite a CIBSE convened Industry Advisory Group proposal for an interim step 10% improvement in standards in 2016. There had also been no indication of any proposal for changes to existing buildings standards.

Welsh Standards

The Welsh standards in 2014 introduced some better standards for extensions and introduced some basic consequential improvement requirements for upgrading existing buildings alongside their extension, but the English Part L 2013 change decided against consequential improvements, or the ‘conservatory tax’ as the Daily Mail dubbed it.

Scottish Standards

Meanwhile the Scottish New Part 6 of the Building Standards comes into force in October this year, with a 21% improvement to new dwellings standards and a 43% improvement for new non-domestic buildings, leaving England trailing in the dust on the journey to lower operational cost and lower emissions building.

Regulatory Gap

There is already a distinct regulatory gap in compliance with new standards, with transitional arrangements allowing builders to commence sites and then to ‘bank’ them, fixing compliance requirements. These provisions typically result in an 18 month to two year lag between introduction of new standards and when the larger house builders start to build to them.

The government’s statement notes that they will “keep energy efficiency standards under review, recognising that existing measures to increase energy efficiency of new buildings should be allowed time to become established”.

I suspect that it is a combination of the costs of the allowable solutions, the lack of firm detail and the short remaining timescale that has lead to the government dropping allowable solutions requirement and the updated approved document L1A target; but you would have thought that at the least, the expected on-site carbon compliance requirements and update to SAP should have been adopted.


I stated in a blog post just before the election, that zero carbon was unlikely to happen ‘on-site’ at all and that the best that we were likely to get, was a better standard on-site and allowable solutions to take us the rest of the way. In that post I noted

“So, when will Zero Carbon start?

Sadly, it probably won’t – the best we’ll get is closer to it.”

Now it seems that my answer should have been ‘it probably won’t’. I hate it when my pessimism bears fruit.

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Jon Ducker is a qualified energy assessor working for Kingspan Insulation Ltd. He has an extensive knowledge of energy efficiency, renewable energy systems and sustainability in buildings with an expert knowledge of the relevant sections of buildings regulations and standards and their interactions with SAP. He provides authoritative advice regarding energy assessments for a wide range of public and private sector clients.

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