Energy Efficiency Regulations for Zero Carbon Homes

Housing Minister Grant Shapps recently re-affirmed his commitment for all new build homes to be zero-carbon from 2016. He also confirmed the work, carried out last year for the previous Government, in creating the ‘Fabric Energy Efficiency Standard’.

Is the timescale realistic and what needs to happen to achieve this? The first factor to consider is the definition of zero carbon. You would think zero means ‘nil’ but, in fact, the standard being aimed for is not nil – it’s 30%!

Within the new energy efficiency regulations zero- carbon actually means a reduction of 70% from the 2006 permitted level of emission; still quite an ambitious target. To achieve this will not simply involve building homes with extra insulation; it will be about sustainable architecture designed for energy efficiency and fuel conservation – and it is complex!

Energy Assessment for Building Regulation Approval

From October 2010, energy assessment will have to be submitted as a part of the Building Regulation application. The new build design stage will involve integrating a combination of energy efficient systems and products which must perform as specified; not just in theory but in practice. Recent studies have shown that the energy performance of new homes when built often falls a long way short of that expected by the design stage energy assessments. This may be due to the modelling technique being wrong or the standard of build being poor, or both!

We need to ‘get it right’ every time. Today, it is very rare for new homes to have structural, fire risk or sound transmission problems, but when it comes to meeting building regulations for energy efficiency, so far, there has not been the same level of rigorous procedure. The house building industry needs to have a much clearer and consistent understanding of the ultimate goal and be given time to respond.

So, is the Methodology for Energy Assessments for New Build Inadequate?

The existing energy efficiency/carbon emission compliance tool – the Standard Assessment Procedure (SAP, also used for producing energy performance certificates, EPCs) compares well with other modelling processes, especially for heating, but it could be better in, for example, energy use for water heating, new technologies and innovative design.

Sustainable architecture designs for low energy homes could result in a reduction of air quality and day lighting, but as information on these is already entered into SAP calcs there is an opportunity for designers to have the energy efficiency/carbon emission information whilst also providing a check for other aspects of their design.

And what about Quality of Construction – Why is this a Concern?

One good example of how things can go badly wrong on site: The Air Pressure test results from two different examples of the same house type, built on the same site, varied by almost 100%, despite being built by the same contractor. The issue was with build quality: We have to understand whether architects are creating un-buildable design stage details or whether there is a lack of construction skills and understanding to deliver the approved design. (more…)