The Larch Passivhauss in Wales, designed by Bere Architects.
There has been no official announcement, but many in the housing sector believe the Government has fallen out of love with the Code for Sustainable Homes. For the time being it remains a requirement for social housing, so it’s not yet dead, but it may only be a matter of time.
This will be a blow to the many code assessors (including ourselves) who have spent years wading through oceans of paperwork, code revisions and a bureaucratic quagmire to help design homes with a lower environmental impact and running costs than those complying with Building Regulations alone.
And it further complicates the planning arena where many local authorities, encouraged by previous government policies have incorporated higher code ratings into their Core Strategies often in the face of vociferous opposition from developers.
What the CSH does (did) well is to pull together a spread of environmental indicators into a single rating system, with easily understood levels.
But with the focus on reducing emissions, rather than energy demand it has produced some anomalous and possibly unintended results. Homes can achieve on-paper carbon reductions with only moderate improvements in the efficiency of their fabric and the large scale application of renewables or low carbon technologies. Though recent revisions to the technical guidance have sought to put more emphasis on ‘fabric first’ contrast this with a passive design approach where the emphasis is firmly on reducing fabric and ventilation heat losses to the point where these can be met for free by heat from the sun, occupants and appliances, leaving a much smaller energy demand to be met renewably.
Even the most ardent advocate of renewable energy will be hard pushed to argue that renewables will have a longer life and lower running costs than insulation, and thermal mass. The passive approach may not be as sexy, and sells far less ‘stuff’, but as a recent review of council houses, built in Salford 30 years ago shows, it works, producing low running costs, very low emissions, durability and comfort with only marginally higher build costs. http://tinyurl.com/5rscy4a
So if the Code for Sustainable Homes finally succumbs to a lack of government support what will take its place? The Government could continue (as it has said it will) to shoe-horn the energy and CO2 modules into Building Regulations. But this far from straight-forward and leaves a very big question mark over other important elements such as materials, ecology, management and water.
Developers are showing increasing interest in the code’s foreign cousin, Passivhauss. According to the BRE, Passivhauss is the fastest growing energy performance standard in the world with 30,000 buildings completed to date, the majority of these since 2000. As the name suggests homes built to the Passivhauss standard are passively heated and cooled, (what are now being described as ‘self-heating’ and ‘self-cooling’ homes.
But why the interest in this passive approach? For one thing the emphasis on buildings with high thermal mass works well with traditional (heavy) construction techniques with which the UK housing sector is very familiar. For another, as homes get more efficient the requirement for space heating falls. This makes the financial case for approaches such as district heating and CHP (both gas and biomass) more difficult and leaves developers with the question of who will manage the system in the long term. So why not produce passive homes which eliminate the major infrastructure cost associated with space heating.
Quite how much longer the Code for Sustainable Homes will survive has yet to be seen. But if Passivhauss moves in to take its place that will be no bad thing for householders and carbon emissions alike.
© Climate Works Ltd, October 2011.
Climate Works has developed and runs two training courses Towards Zero Carbon Development and Planning for Zero Carbon Development which cover how to integrate passive heating and cooling techniques into building design and planning policy. You can find further details here: