Whatever the outcome of the UK government’s strategy for the various proposed eco-town projects (it will probably be late summer before the final shortlist is announced) the eco-town initiative has generated some good ideas that may become standard solutions for future buildings. The principal message (as we all know by now) is that lifestyle

European Initiatives …  Architects, engineers, planners and sustainability experts are looking progressively more to the eco-towns on the continent as models of what could be achieved in Ireland or the UK . Projects in Germany (Freiberg), Denmark (Copenhagen) and Sweden (Malmö and Hammarby Sjöstad – suburbs of Stockholm) all demonstrate how lifestyle changes lead to reduced environmental impact. Check out architecture week for Tango Housing in Malmö by Moore Ruble Yudell Architects.

Green Lifestyle … People have changed the way they travel and the way they live domestically and they have managed to cut their energy use and carbon footprint without affecting their quality of life. This has persuaded the British government to cite them as inspiration for the UK’s own eco-town initiative.  In Ireland and the UK, we use power stations, import our fuel from outside the country and then throw all the heat away. In Holland and Germany, they are not afraid of being accused of taking the sensible approach and try to keep their energy within the community. In Sweden, historical ownership is not allowed to impede rational measures for sustainable development. We have much to learn from these approaches.

In Europe, there is also a major difference in the approach to solving national issues such as the one of reducing carbon output from housing. There, the initiatives tend to be directed by local authorities, with much greater emphasis on collaboration between the private developers and the local authorities. Here, our local authorities mostly do not possess the resources or funding and developers are not given the same encouragement, back-up or indeed, incentives. The big house-building firms in Ireland and the UK  do not believe that large scale development using the Passivhaus standards is commercially viable here at present, and so use this as an argument for aiming towards lower standards than can actually be achieved. I would have thought that the main objective when designing an eco-town would be to achieve the best possible standards of energy efficiency.

Transition Towns Initiative …  For those of you not already aware of this movement, have a look at the question posed on the Transition Towns site  for all those aspects of life that this community needs in order to sustain itself and thrive, how do we significantly increase resilience (to mitigate the effects of Peak Oil) and drastically reduce carbon emissions (to mitigate the effects of Climate Change)?”

Big question – but change will be achieved if enough people want it.

I intend over the next few weeks to explain all the main elements of passive house, from triple glazed windows, through heat recovery ventilation, airtightness and so forth. I would like firstly to explain what exactly a passive house is, however, so here goes.
Firstly, I need to clarify that the term passive house is perhaps a little misleading because you might have the wrong impression that it concerns only ‘houses’, but that couldn’t be further from the truth. I have visited a range of passive house projects across Europe, including passive house schools, passive house offices, passive house community centres, passive house churches and, believe it or not, even a passive house fire station. So, you can build pretty much anything to the ‘passive house standard’ (including a passive house house, by the way!). 

The next common urban myth about passive houses is that you have to follow a very strict design style in order to achieve the required standard. Week in week out we receive planning permissions drawings from people who want to test their house design to see if it can achieve the passive house standard. We’ve seen all sorts of shapes, sizes and orientations and the vast majority of them, with enough insulation, high quality glazing and good airtightness can pretty easily achieve the required standard. So, the passive house standard is not as limiting as many people assume in terms of building design.

Next, I need to emphasise that the passive house is not magic. You’ll read from time to time that passive houses are buildings that don’t need heating, but that is simply not true. All buildings in a climate even as mild as Ireland need some form of heating – even if it is a tiny fraction compared to a conventional building. As a example, my demonstration home, ‘Out of the Blue’, in Wicklow, uses just 10% of the heating energy compared to a conventional house, but it does need that 10%. So a passive house is not a zero-heating house, but a building that needs a very small back-up heating system and without the need for radiators or underfloor heating.

At a more technical level, there are three criteria that must be achieved in order to reach the passive house standard, as follows:
- Maximum annual space heating demand per square metre of 15 kWh
- Minimum airtightness of 0.6 air changes per hour measured at a pressure of 50 Pascal
- Maximum annual primary energy demand per square metre (for all electrical use, even white goods) of 120 kWh

So I would conclude that the passive house standard is a method of design and construction that delivers a building with a very low heating energy demand. Nothing more, nothing less. I will be giving a step by step guide on the main elements of the passive house over the next few weeks, so stand by.

What’s a green building?  One covered in solar panels and bristling with turbines?  One that proclaims its greenness by looking different?  One that costs 15% more than a ‘conventional’ building?

For British architect Howard Liddell, the answer is none of the above.

At a one-day symposium on sustainability in TCD recently, Liddell outlined his ideal green building: it looks conventional, costs no more to build, but is so well insulated and airtight that there is almost no need for heating, and certainly no need for what he calls “eco-bling”.

The main problem, as he sees it, is that technologies are an expensive add-on with a long payback time.  The sensible and cost-effective route to a green and eco-building is effective insulation.

Unfortunately, eco-bling is flavour of the month, and Liddell was particularly critical of new building regulations in some British local authorities that now require a minimum 10% of on-site renewable technologies — expensive and ineffective wind turbines on top of buildings, when they should be on remote, windy sites.

In an inspiring presentation, Liddell,  principal architect with the British-based Gaia Group, argued that we need to make insulation sexy. “Eco-minimalism, not eco-bling.”

Effective insulation alone, he said, could halve the energy demand, and significantly reduce fuel poverty.

The main challenge, in Ireland as in Britain, will be to retro-fit a high standard of insulation to existing buildings. What’s more, each building will need an individual solution.

And you can’t just fill cavity walls with foam, he argues: those walls were designed to breathe so, if you block them up, you simply create a moisture problem on the inside.

Likewise, it is not enough to seal every crack with gunge.  For a start, the gunge will crack, so you won’t get an airtight seal. And again, you have to worry about moisture buffering.

Other issues that he identified are: effective testing of a building’s air tightness; and indoor air quality in an airtight building (especially moisture content, and off-gassing from materials and furniture), making choice of materials essential.

To be truly ‘green’, he recommended using sheep’s wool insulation, as he felt there were issues with the chemicals used to treat insulation made from recycled newspaper.

In a wide ranging and fascinating talk, Liddell also recommended: mass-timber construction (not just beautiful to work with, but also good for sequestering carbon dioxide); ‘nail-free building’ (securing well designed, well fitting pieces with just a few screws), which doesn’t damage the wood and makes repairs and alterations, and recycling much easier; and low-flush toilets that use less than 2 litres of water — already achieved on aircraft toilets.

If Liddell is right, and every building leaves a customised solution, then on the plus side this would be a major job creation project architects, and the insulation and construction industries.

For more on Howard Liddell’s eco-minimalist architecture, check out his new book here.

Mary Mulvihill’s new guide to easy, sustainable living is Drive Like a Woman, Shop Like a Man (2009).  Click here to suggest a tip, and be in with a chance to win a copy of the book.

(c) Mary Mulvihill 2009  http://marymulvihill.net/

If you are planning any eco-building scheme, then you will place green energy somewhere near the top of your list. It is very easy to simply look at the descriptions issued by the manufacturers of renewable energy production systems, but how do you equate the figures with what you actually need? This is a question that I am frequently asked and there is no other way to answer it than to use …

…Simple Mathematics …  The following is simply an exercise in statistics and does not address the ethical issues of choosing energy supply, but all the same it is a task which must be tackled before any sustainable building can be successfully designed. For those of you who grow pale at the sight of calculations – then accept my apologies; but the concept is an essential element in good eco-design, and if need be, you ought to obtain balanced professional guidance.

Energy Units … You should calculate energy requirements by using units of energy – kilowatt hours in terms of time (kWh/day) – in other words the amount of power used over 24 hours. In the UK, the total amount of energy consumed * by each person is reckoned to average about 125 kWh/day, but this figure obviously covers all power usage. Depending on the source of information, it is estimated that the average UK home uses electrical power of between 3300 kWh/year (or just over 9 kWh/day) and 4700 kWh/year (about 13kWh/day). Northern Ireland’s domestic consumption for 2007 averaged 4400 kWh/year (12 kWh/day). Ireland’s consumption per capita is roughly equal to the UK. Check your electricity bills to see how you compare.

To give an example of how appliances measure up, if your home uses an average of 500 W (0.5 kW) then it will consume 12 kWh/day. If left switched on all day, an energy-efficient (11W) light bulb uses (0.011 x 24) = 0.264 kWh/day and a desktop computer using an average of 125W will consume (0.125 x 24) 3 kWh/day. It is not so simple to calculate the power consumption of some appliances just by checking out the wattage since power demands can fluctuate, e.g. fridges use power according to their ‘chill’ setting in relation to the ambient room temperature. Don’t forget that other non-electrical appliances such as stoves or oil burners also need to be included.

Renewable Energy … Renewable-power generating appliances need to be compared to see what they can achieve for you. Roof-mounted micro-wind turbines are probably not very effective in providing for your overall electrical needs. It has been estimated that a “600 W” micro-turbine mounted on a typical roof in England generates only 0.04 kWh per day – about 7 per cent of the power used by an 11 W light bulb.
In contrast, roof-mounted solar water heaters make good sense. Even where the sunlight levels achieve only about 30 per cent, a 3-square-metre panel can supply on average about 3.8 kWh per day (i.e. perhaps half of a typical family’s hot water).

Other technologies are often viewed as ‘less green’, such as heat pumps; but if they drew power solely from renewable sources (i.e. wind farms, etc) then they would be a logical environmental choice. Some of the newer ones can deliver as much as 4.9 kWh of heat in the form of hot air or hot water, using 1kWh of electricity to do so.
A final thought… before paying out money to provide energy, first put into action ways of reducing your power requirements.

Greetings from Frankfurt where I am attending the 13th International Passivhaus Conference, along with a group of about 50 other Irish delegates. For two years running the Irish delegation has been the largest foreign group at the event. We’re a force to be reckoned with.
The closing speech by Professor Dr. Wolfgang Feist was, as usual, highly rousing. He joked if people want cheap buildings, they should live in tents! He highlighted that the cost of Passive House elements is continuously dropping, with a new generation triple-glazed window now costing just 250 Euro per m2, a staggering 50% saving. Feist concluded that soon there will be no difference between the cost of a Passive House and that of a ‘normal’ house – eliminating any argument against this construction method.
Next year’s conference is in Dresden, 28th to 29th May 2010. If you’re interested in attending, I’d suggest you contact the SEI Office in Cork on 023 63393. It will be another sellout.
On the social side of things, we were treated to a banquet on board a large cruiser on the River Main accompanied by music, including the occasional Irish jig no less. I felt obliged to teach some Swedish and Chinese colleagues the finer points of the Siege of Ennis, which brought a whole new meaning to the concept of ‘Riverdance’.
I’m thrilled I went to the conference. I feel like I’ve had a complete blood transfusion, all tingly and buzzing and ready for action for another year. I’ve had my fix.