Passive house panel sees need for retrofit solutions
Paris, 28.04.2009 - REEEP International Secretariat
When REEEP hosted a round table on low-energy housing alongside the ee Global conference in Paris on April 28, 2009, the panel quickly shifted from a discussion on the barriers to new net-zero energy construction, to what they saw as the more critical issue: the need to retrofit existing buildings to a low- or zero energy standard.
The discussion kicked off with the observation that the passive house term is often tossed around without much regard for accuracy. “The passive house, or ‘passivhaus’ in German, is actually a specific, clear term referring to a tightly defined standard by the inventors of the movement,” noted Lone Feifer, architect and manager of VELUX Model Home 2020 project, “and to be fair to those founders, a better generic word for our discussion might be low-energy house or net-zero energy house. In any case what we’re all talking about are buildings with three main characteristics: a tight and well-insulated envelope, the use of renewables, and high quality of life.”
Yet the image of these building with the public lags behind reality. ‘’We all too often experience the ‘4 C prejudices’; the lack of comfort, high costs, too complex to build and poor creative design” says Werner Hansmann, Vice-President of EURIMA and International Marketing Director of SAINT-GOBAIN ISOVER. Overcoming these prejudices is one of the aims behind the Model Home 2020 project, in which VELUX, the roof window company, has set out to build six low-energy homes in five countries over the next two years. These are all carbon neutral houses, based on renewable energy sources, and will be sited in climates ranging from Austria to Scandinavia. They also aim to use building techniques and materials in keeping with local practices.
As important as pilot new-build projects are, the panel quickly came to what they saw as the nub of the challenge on low-energy housing: the biggest issue isn’t with new buildings at all, but in how to deal with the existing building stock. “Here, we need innovative answers for retrofit solutions; maybe things like prefabricated facade elements that could include ventilation systems,” said Hansmann. “But even with existing solutions we have proven the ability to reduce the energy consumption up to 80 or 90%.”
“People don’t realise the scale of improvement needed and the urgency connected with this issue. Some 14.8 million homes in France need to be retrofitted. That amounts to 1000 homes per day for the next 40 years” said Constant van Aerschot, Director at Lafarge and Co-chair of WBCSD Energy Efficiency in Buildings project. “Given the sheer scale of the challenge, the market alone fails. Measures are needed by government, industry and stakeholders to mobilize and address the issue. There are 130 million buildings in Europe.”
“The new U.S. administration’s plan to weatherize 2 million homes is a step in the right direction, but compared with 80 million households in the country that need weatherization, it’s just a start. What’s really needed is to set stringent new efficiency standards and to make enforcement key,” noted Ken Mentzer, President and CEO of the North American Insulation Managers Association. “In drumming up public support for this, talking about reductions in kWh per home just isn’t going to capture the public imagination.”
In this connection, he also made a plea for more practical action: “Let’s not wait around for the perfect net-zero technology. If we start now with ‘passive-ready’ renovation and construction, leaving space for air interchange conduits and systems, it would be a more useful approach than waiting for the perfect technology. In the short term we’ll get huge savings in conventional heating and cooling costs, and it still moves us toward the goal.”