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Strategic support for energy efficiency and sustainability

Eight key questions for 2012

06/01/2012 16:08:31

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In the drive for good, low carbon homes, there is clearly a case for constantly pushing the envelope further and faster - in which instance our national policies could be accused of lacking ambition.  Cutland Consulting would argue, however, that more can be achieved by taking a less extreme position.  Consider the following eight questions, which will feature heavily during 2012...

1.  Passivhaus: can it work?

Is Passivhaus a radical and profound new invention that will change the way people think about housing design and construction, or is it just a re-stating of the same principles of low energy design that we first learnt over 20 years ago?  Some would say that the established way of procuring buildings needs to be torn up, because there absolutely has to be an airtightness champion, a full time clerk of works, 70 instead of 17 drawings per housetype and an obsessive attention to detailing.  Others would say that the energy evangelists are doomed to fail if WE can’t find a way to make OUR stuff fit in with the national developers’ model of mass housebuilding, both financial and technical.

A word that we tend to use a lot at Cutland Consulting is “pragmatism”.  We fundamentally believe that to make a difference - to make it stick – we evangelists have to ‘get real’ and operate in the big bad world.  If that means suspending or compromising some of our high principles then that’s a price worth paying.

2.  Zero carbon: good or bad?

Cutland Consulting applauds the previous Government’s decision to commit the UK to zero carbon newbuild in an ambitious timescale.  Inspiring leadership is lacking in the world at the moment.  As for the definition, whilst the removal of UNregulated energy in March 2011 gave out terrible messages to industry, we always thought that including it in the first place was a step too far.

3.  Allowable Solutions: a cop-out or sensible?

Clearly sensible.  As long as DECC and DCLG retain the concepts of a mandatory fabric standard plus mandatory maximum emissions arising from the on-site applications, and as long as the Allowable Solutions pot is properly calculated, administered, policed and protected against other Government departments raiding the pot, then it’s just pragmatism in action.

Incidentally, the concept of an energy fund - central to the Allowable Solutions approach - is not ‘offsetting’; it is a mechanism that neatly resolves disconnects between a housing scheme and an Allowable Solution project – ie. it sorts out issues of TIMING and/or GEOGRAPHY. 

4.  The fabric standard (FEES): is it set at the right level?

At one extreme, Approved Document L1A 2010 corresponds to a space heating demand around 48-60 kWh/m2/yr.  Towards the other extreme, Passivhaus sits at 15 kWh/m2/yr (although translating this into the Part L conventions makes it more like 25-30).  And FEES is set at 39-46 kWh/m2/yr depending upon built form.  So in essence Building Regs are at 50, Passivhaus at 30 and FEES at 40 (ie. pretty much in the middle).  That feels about right, especially given that it will be the law in only FOUR years’ time.

5.  Zero carbon by 2016: can the UK meet this deadline?

Probably not.  2020 is more realistic.  But given the usual transitional arrangements, and the lack of starts that are widely anticipated over the next few years, it’ll probably pan out to be 2020 anyway.

6.  The ‘performance gap’: who is to blame?

The energy community is in the habit of saying that poor quality construction is to blame, but Cutland Consulting is not entirely sure that that’s fair.  Consider the classical scientific method… it never questions REALITY, by definition.  Scientists use a model to make a prediction, observe the facts, then if the reality doesn't match the prediction they change the prediction.  In other words, scientists ‘model out the unreality’.  Relating that to the housebuilding context, if it’s found that a certain construction has a calculated U-value of 0.2 but when it’s built it turns out to be 0.5, then surely it’s equally appropriate to change the U-value calculation methodology as to blame the builder?

We’d also like to see the supposed “growing body of evidence”, rather than just the Stamford Brook and Elm Tree Mews results again and again.  There are many possible causes of the performance gap, and the UK needs to take a far more SYSTEMATIC approach to diagnosing and fixing it.

7.  Would Passivhaus help to close the performance gap?

Not in the pragmatic mass-market world.  It would just alienate the volume housebuilders, most of whom already think the evangelists are misguided and out of touch.  What WILL help in that market is a straightforward focus through the design stage on simplicity and buildability, which eliminates the need for site operatives to improvise details on site and reduces the workload of policing overly-complex standards and regulations.

8.  Monitoring: should it be compulsory?

For various reasons we don’t believe that co-heating tests are the answer.  Those tests involve heating an empty house to 25°C using on-peak electricity for two weeks in mid-winter, and while this might be OK for an academic research paper it is unlikely to be acceptable in the pragmatic world of the volume housebuilder.  Instead we advocate a national programme of basic monitoring of fuel use, creating a statistically significant data set which effectively eliminates variations in occupancy patterns.  


Which way these things go remains to be seen, but what is certain is that the eight questions will get asked a lot during 2012.   

 

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