What is the thinking regarding ‘small sites’ exemption to zero carbon?


In the Queens speech earlier this year, the government announced an exemption to their 2016 zero carbon requirements for small developments of new homes, with a consultation to come later on what this exemption would involve. That consultation has now been published…

New buildings are supposed to be ‘nearly zero energy’ by 2020, but to do that, a very good building fabric, good services and renewables will be needed. These levels have been shown to be achievable on-site for some dwellings, but aren’t always easy to achieve for all dwelling types.

The government previously decided that the 2016 new homes on-site requirements would be set at roughly equivalent to ‘Code 4’ (which is 19% better than the L1A 2013 target), with the remainder of zero carbon / zero energy coming from ‘allowable solutions’, i.e. offsetting whatever isn’t achieved on site by energy and carbon saving elsewhere. They also decided that small developments would have some degree of exemption from this.

A consultation has now been published as to what this exemption will involve as ‘Next steps to zero carbon homes: small sites exemption’ and this will close on 7th January 2015.

The questions covered include whether:

  • The exemption should be targeted at site size, developer size, or a combination of both?
  • If site size, what level should this be set at and why? 
  • If developer size, what criteria should be set and why?
  • What should the scope of the exemption cover? An exemption for the allowable solutions scheme only, or an additional exemption from Building Regulations requirements?
  • What are the views on the proposed review period for the exemption?

My personal view is that there shouldn’t be any exemptions at all, but seeing as the government has already decided that there will be, it should be limited to only small sites of 1-2 houses; such sites already currently have an exemption made for air tightness testing (so there is a precedent already in regulations that building control will be familiar with to treat those developments slightly differently).

It would be important however to ensure that larger sites aren’t split into batches to fall within any exemption allowance.

Whilst longer term, we need to be pushing towards net zero energy and emissions for all homes (not just the new ones), these smaller developments can be trickier and more costly to improve, lacking economies of scale and not being appropriately sized for demand to benefit from some technologies.

Such an exemption would give some benefit to small and self-builders to encourage more new dwellings to be built via this route, but the exemption should be for a limited time only and reviewed in 2019 ahead of the EU 2020 requirement for all new homes to be nearly zero energy.

From years of involvement through energy assessments of small projects (as well as large), it is usually the smaller developments with people building for themselves, or heavily involved with someone building for them, where greatest attention to detail is made and often it is self-builders who agonise most over all the options, looking at future running costs, low maintenance solutions and trying to build the best that they can, because they will be living in it.

An exemption based on company size might result in larger companies forming lots of smaller ones, or getting around the more stringent requirements via subcontracting or other means; it would be difficult for building control to assess which sites should comply with higher standards and which don’t have to. A two-tier system along those lines is ripe for abuse and confusion.

Many responsible larger companies do exist and do have high standards and reputations for sustainable, energy efficient buildings, but it easy to see how others might choose to go down the route of less costly minimum compliance if that option were available.

Any exemption from zero carbon requirements should only apply to the allowable solutions element, with the on-site requirement set for all, thus retaining a single tier of building regulations on site standards. Again, that would ensure that all new dwellings are at least notionally likely to be of a similar on-site minimum standard.

It’s worth noting that the updated impact assessment published earlier this year showed that the extra costs to achieve Code 4 over usual industry practice (L1A 2013) are hardly excessive, especially when the energy efficiency savings to the house purchaser are considered.

The costs for smaller developments might be slightly higher than for the medium sized development costs that were referenced, but it shouldn’t be massive amounts more and those higher standards should produce homes that are cheaper to run, covering the higher up front costs in fairly short order.

The government massively scaled back on the original zero carbon homes vision and then on the levels recommended following considerable work by the zero carbon hub; adding loopholes that might result in large scale avoidance of even that reduced aspiration would be totally irresponsible.

We should be aiming for building better, more energy efficient, more sustainable homes, not introducing loopholes to avoid doing so.



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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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