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THE CASE FOR MAKING PASSIVE HOUSE MANDATORY There is a growing sense that passive house’s time has come. Following on from the examples set by umpteen municipalities and local authorities in continental Europe, there are signs of public bodies in Ireland and the UK making the passive house standard mandatory. Jeff Colley describes the rapidly unfolding events and puts forward some key points to take note of as events unfold. Dún Laoghaire-Rathdown County Council’s decision to make the passive house standard mandatory for all new buildings in the county – albeit subject to public consultation – may prove to be the decisive breakthrough to make genuinely low energy building mainstream in Ireland – and may help to cajole the UK to keep up. Much of the impressive recent growth in passive house in the UK has been driven by the public and non-profit sectors, with increasingly substantial passive projects such as social and affordable housing schemes, educational and civic buildings. In that context, Exeter County Council’s recent decision to build its own housing to the passive house standard was welcome but not entirely surprising news. Meanwhile Kirklees Council are proposing to make passive house mandatory for development on the council’s land, including when that land is sold. Short of changing building regulations nationally, the initiatives taken by Exeter & Kirklees point the way to achievable passive house policy in the UK, for the foreseeable future. In a brazenly retrograde move, secretary of state for communities and local government Eric Pickles has prevented English local authorities from going further – with the other UK regions out of his reach thanks to devolution – by removing a clause in the Planning Act that permitted councils to set their own energy efficiency standards above those contained in building regulations. Essentially this means English councils can’t impose a planning requirement that housing must be more energy efficient than the mediocre levels set out in Part L, though the renewable

energy sector successfully lobbied for councils to retain the power to set renewable energy targets in planning. The public consultation on Dún Laoghaire-Rathdown County Council’s draft county development plan opens on 2 March, and the early signs indicate that the discussion will include some fallacies, unfounded assertions and hackneyed objections that mustn’t distract us from the facts. The following list includes some key points to keep in mind as events unfold. Passive house needn’t cause construction cost increases In Ireland this is already true, due to changes to Part L of the building regulations. It should also be the case in the UK from next year, when the mooted zero carbon homes deadline kicks in. According to the Department of the Environment, the average new Irish home that meets minimum compliance with Part L is expected to hit a calculated primary energy demand of 60 kWh/m2/yr1 – a mid A3 BER. That's an average across all house types. More compact dwelling types such as apartments tend to be in or around or below 50 kWh/m2/yr, which means an A2 BER. In urban and suburban local authorities, the development is likely to include an emphasis on more compact forms such as apartments and terraces so for many developers, an A2 is already a minimum requirement. In fact designing to the passive house standard may reduce construction costs in many cases. Building regulations are completely disinterested in the form of a building. If I ask an architect to

design a 200 sq m home for me, and I want a H-shaped bungalow upon which to land my helicopter, Part L’s only concern is that I reduce the energy demand of that building by 60% compared to a poorly insulated H-shaped bungalow. If I had instead asked for a two-storey rectangular building, my 200 sq m would have a much tighter footprint, meaning considerably less surface area for roof, floor and walls per sq m of floor area, and substantially reduced spend on materials. It would also mean reduced heat loss, for the same reason. There are other potentially significant construction cost savings too – such as those achieved by reducing the size of heating systems, given the tiny space heating loads of passive houses, and by avoiding the need for repair or replacement due to surface or interstitial condensation caused by less robust energy efficiency approaches. Economies of scale and increased competition are already bringing prices down, with a number of major construction brands coming into the passive house space, as many of the adverts in this and previous issues of Passive House Plus have demonstrated. It’s possible to build an expensive passive house too, of course. Some – but far from all – of the clients who build passive houses are willing and able to pay for the highest quality materials, and for other sustainability features (which may or may not add cost). So a high spec passive house must be compared to the cost of a high spec A2/A3 house. Conversely, we have previously published examples of passive houses being built for in or around €100 per sq ft – prior to the benefits that economies

Profile for Passive House Plus (Sustainable Building)

Passive house plus issue 10 (UK edition)  

Passive house plus issue 10 (UK edition)