The Eco Retrofit Carbon Con Trick

Thanks for the great debate on the last post. As ever your comments bring more light than my initial thoughts. In that spirit of starting the conversation here is my take on last week’s Edge Debate on low carbon buildings.

It is not widely appreciated amongst the building buying public that developer’s claims for the energy performance of buildings are based on computer models of anticipated performance rather than the actual performance of the building. I suspect that many developers aren’t entirely aware of this either and for the most part their environmental consultants aren’t telling them.

However, within the consultancy profession the idea that buildings do not perform as anticipated by models has been well known for some time. At the Edge Debate on the subject last week, the godfather of sustainable building engineering Max Fordham made the point that engineers have long known that there has been a factor-of-six-difference between the highest and the lowest in the energy performance of apparently similar building types.

This shouldn’t be unexpected as no buildings are identical either in location or in users so a bell curve standard distribution of performance is to be expected and a factor of six between the outliers in either tail is reasonably typical. However, the computer modelling approach to predicting energy performance has to work from average performance. The debate suggested that perhaps consultants should, instead of giving a single point estimate, give a range. Others suggested that grading a building as having a 50% chance of being somewhere between an EPC D and B would severely undermine the signalling power of the system.

The main focus of the debate was the work the Carbon Trust had been doing on the actual energy performance of existing commercial buildings after refurbishment and on new commercial buildings and the comparison of this with the pre-refurbishment and development predictions.

This and other similar data is nicely presented on the Carbon Buzz website and Carbon Trust have done more detailed reports on their work here.

The simple message from this data is that the EPC and similar ratings that we use are generally wildly optimistic. At igloo we have done similar post occupancy reviews and our findings were exactly the same.

The reasons for this seem to be numerous but some of the most important ones that came out in the Q&A at the debate included poor workmanship, systems that were either too complicated for the building managers to operate or where building managers hadn’t been properly trained at handover and the behaviour of building occupiers.

So there is a dilemma here. There is clearly a danger of discrediting energy efficiency rating systems and therefore destroying their main purpose which is to change behaviours of clients and customers towards requiring greater energy efficiency as seems to be working so well in white goods (fridges etc) and to a certain extent with cars. There is also a danger that Government doesn’t feel able to use these ratings systems as the basis for other regulation and incentives such as the idea that Stamp Duty (SDLT) could be lower for energy efficient buildings and higher for inefficient ones and for the future banning of the sale and letting of energy inefficient buildings.

On the other hand, performance information is important in helping us to achieve the goal of increasing the energy efficiency of buildings. At igloo we recognise that in energy efficiency, and in wider sustainability, society, ourselves and our occupiers are on a journey. Our green lease includes a duty of collaboration and we have found that occupiers are enthusiastic in pursuing, together with us and each other, continuous improvement in sustainability for themselves and the buildings and neighbourhood. Knowing how we are performing is critical in understanding how and where we can improve.

In the budget, the Government recognised this problem in relation to new homes by accepting the recommendations of the Zero Carbon Hub task force chaired by David Adams that building regulations should in the future be based on ‘as built’ performance rather than design predictions. This is a fundamental change and challenge.

The roll out of smart meters starting in 2014 and proposed to deliver 53 million meters at an estimated cost of around £11bn is also part of this process. The meters will give us all much better visibility of our energy use and as a result are expected to lead to a reduction in energy used.

But lurking behind all this activity are some more fundamental questions. Should we be substantially simplifying building management systems for example? The trend to air tightness has raised many practical issues that have resulted in performance not matching expectations. Air tightness tests are done with trickle vents temporarily sealed up, users like to open windows for all sorts of reasons, relatively small heat sources like lights and humans cause overheating that can only be addressed by the installation of mechanical ventilation, activities like cooking, painting and cleaning cause odours and even the build up of potentially hazardous gases and so on.

Some organisations like the Prince’s Foundation are advocating a move back to buildings that can ‘breathe’ and for the better use of traditional, well-understood technologies like tall Georgian sash windows that, when opened at top and bottom in rooms with greater height than we have today, produce a circular cooling and ventilating airflow. These approaches can be too easily rejected by services engineers schooled in and excited by ever more sophisticated computer controlled engineering.

There are other balances to be struck, for example in window size in relation to heat gain and loss, the need to use lighting, privacy and health, happiness and wellbeing. Curtains and shutters are examples of traditional technologies that have broadly fallen off the table in debating these issues. And our technologies need to cope with the different environmental conditions across the UK today as well as the risks of either warming or, subject to the Gulf Stream, cooling in the future.

And in the middle of these debates the use of power to drive appliances, which are the major users of energy in commercial buildings and which are now excluded from the zero carbon definition for homes, will be addressed by different tools like the EU Emissions Trading Scheme.

These complexities play to another of Max Fordham’s points, which was that everyone in society should at least be attempting to reduce energy use in buildings although this begs the questions about how fast and how far and how to balance trade offs.

There is also the debate about whether these issues are simply too small or too difficult or too prone to perverse outcomes and whether the solution will lie with, for example, more efficient use of buildings where perhaps working from home or having multiuse spaces which are used more, and therefore more efficiently, through the day and the week thus reducing the number of buildings we require.

The direction of travel though seems clear, as regulation and markets (as energy prices increase) move us incrementally towards greater energy efficiency and lower carbon emissions, and although there will no doubt be backward steps along that path, our improved understanding of the inadequacies of our previous measurement techniques will allow us to innovate solutions to move forward again. Whether we will move fast enough or far enough is perhaps the bigger question.

3 Responses

  1. Interesting article. I’m fairly clueless about energy efficiency in buildings, but my own experiences of new build which are supposedly energy efficient would very much support the findings presented here. Whilst I live in a very drafty 1910 house, I much prefer it to my friend’s new build apartment, which is supposedly sealed tight. This has lead to incredible dampness and moisture, with little opportunity to air the flat through windows alone. This is also something I found quite prevalent in many refurbished buildings in Liverpool, whereby the design of the original structure requires internal courtyards or buildings with only one wall which one can vent the units.
    I often think in our quest to get the most energy efficient building we forget the basics – good insulation, proper window fittings (and glazing), orientation of properties to take advantage of environmental conditions, etc will all work to create a building which works well…

  2. The speed of implementation is one of the issues I have with the Code for Sustainable Homes. Whilst I accept that the challenging timetable for zero carbon houses has led to innovation, and to a number of excellent developments, it has also led to increased pressure on the developers to get the most for their investment, with often negative impacts on the livibility of developments.

    Energy efficiency of our buildings does need addressing. However, altering the means of production of how this energy is generated has to be the ultimate endpoint. If the time to do this is bought by reducing the energy demand of buildings, then so be it. If reducing this energy demand means that these buildings become unliveable, then this seems to me to be a mockery of any sustainability credentials it may have.

    Good design can do both. Unfortunately, this is a section of planning that is pretty toothless at the minute.

  3. Good stuff Chris. As you know I was on the panel; for this Edge debate (apologies again for having to leave early to head West) and my focus (in doing the work for the Carbon Trust and since) has been on trying to work through my thoughts on why we (I mean construction professionals) don’t deliver what we say we’re going to or what clients really want (as opposed to what they think they want). (Also, apologies for using so many brackets!).

    My principle point is (and I’m pre-empting what I’m going to Tweet about for the next few days here) is that when a client asks their designers for a sustainable (read low energy / carbon in this case – we’ll talk about the other stuff another day) they think that they’re doing the right thing by asking for us to demonstrate that through EPC or BREEAM ratings.

    I’ll also leave BREEAM for another day and just go with low carbon for a minute.

    As you point out, the energy labelling system works well for household appliances, so why not buildings? The principle reason is that appliances are robustly tested under conditions very similar to real life at the design stage and therefore predictions of energy consumption are pretty accurate – there isn’t that much the user can vary to significantly adversely affect performance. Not so with buildings for a number of reasons:

    1) The ‘energy rating’ we give buildings at design stage isn’t the same as for appliances. Specifically, it isn’t designed to predict energy use in real life merely confirm compliance with Regulations.
    2) The energy rating only covers ‘regulated’ loads. I.e. the fixed systems of the building (I’m over-simplifying here but it’s late and you know what I mean).
    3) The activities of the user can result in signifcantly more energy consumption than would typically be assumed during design.

    There are more, but that’ll do for now.

    A key thread of my thoughts on this is, as Max rightly pointed out, designers know about the gap between prediction and performance (that’s another issue I’ll come to in a sec) and have done for ages, so why is it that they aren’t honest about it (in the vast majority of cases)?

    In some instances, bad designers won’t understand the issue, but where they do, it’s far too often the case that we’re happy for the client to remain ignorant and continue assuming that the EPC A they’ve asked for will mean a low energy / low carbon building.

    Also, and this is my (very slight) disagreement with Max – designers may know through hunch, or having read some of Bill Bordass’ previous work that buildings generally don’t perform as predicted but how often do designers actually try and predict what the building is actually going to do in real life? Answer, pretty much never (I accept there are some exceptions – there always are aren’t there? very inconvenient!). So, how do we know whether the buildings is working as expected or not or by how much it’s deviating? Answer, we don’t.

    Anyhow, I’ve gone on long enough and I have an early start tomorrow so let’s see what people think and if they agree with me or want to bring back the stocks with me in them…

    You can listen to more of what I think on my Twitter (@kevincouling) if you have the time or inclination.

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