Low-Energy Housing – The Passivhaus
With a limited amount of fossil fuels and mounting pressure to reduce carbon emissions, along with an ever increasing demand on housing, the need for more low-energy housing has grown.
The UK is legally bound by the 2008 Climate Change Act to reduce greenhouse gases by 80% by 20501. The Government is facing a rising challenge in tackling household emissions as roughly 45% of emissions come from buildings2.
Due to an increasing population and falling household size, by 2050 there could be 23% more households and, if nothing else changes, a 23% increase in energy consumption3. In order to prevent this we need to modernise energy performance. Building more efficient low-energy housing can help the UK achieve this goal1.
Low-energy housing can use a combination of passive building techniques and active systems to deliver an environment with low greenhouse gas emissions. Passive building techniques refer to the materials that are used to build with and the shape of the building, whereas active systems relates to the use of machinery within the building to reduce energy use4. Although using more renewable energy on site can be beneficial in reducing carbon emissions, in order to make this a more viable option the amount of energy required per household needs to be reduced5.
An example of passive building techniques is the Passivhaus. Defined as a standard by which an overall limit on the energy consumption of buildings can be achieved through the use of passive measures such as excellent insulation, air-tightness, passive solar gains and internal heat sources and high performance glazing, whilst still creating a comfortable and liveable environment. Passive heat sources such as the sun, household appliances, occupants of the house and the heat from the extract air cover the majority of the heating demand6. The residual heat can be delivered by the supply-air if the maximum heating load is less than 10W per square metre of living space. If the supply-air heating is sufficient enough to be the only heat source, the building is called a Passive House7. This means that the requirements for heating or cooling in a Passivhaus is low enough not to require traditional heating/cooling systems6.
In 2010 a 2 bedroom house in Camden became the first Passivhaus in London to become accredited. With its south facing terrace, solar panels and underground area to harvest rainwater, it is cheaper to run than existing traditional houses with 90% lower heating costs and uses less than 15kWh/m² per year of energy for heating. Since then there have been just 94 certified projects, and over 1200 units planned9.
Although a relatively new concept in the UK, Passivhaus buildings have been able to achieve a 75% drop in heating requirements, compared to standard practice for UK new builds7. With a typical home in the UK requiring on average 130kWh/m² per year of energy for heating as opposed to a Passivhaus which requires as little as 15kWh/m² per year, the Passivhaus standard gives a viable method through which regulators and developers can help the UK Government achieve the 80% carbon reduction8.
- Innovative UK Building Performance Evaluation Programme: Findings from domestic projects. Available at https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/497757/Domestic_Building_Performance_Summary_2016.pdf
- Innovative UK Building Performance Evaluation Programme: Findings from non-domestic projects. Available at https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/497706/Non_Domestic_Building_performance_Summary_2016.pdf
- Home Truths: A low carbon strategy to reduce UK housing emissions by 80% by 2050. Brenda Boardman. University of Oxford’s Environmental Change Institute a research report for The Co-operative Bank and Friends of the Earth. Available at https://www.foe.co.uk/sites/default/files/downloads/home_truths.pdf
- Low-energy buildings. Available at https://www.ashden.org/low-energy-buildings
- Delivering a low-energy building. Build with Care. Available at http://archive.northsearegion.eu/files/repository/20140331180312_BuildwithCaReResearchReport-DeliveringaLow-EnergyBuildingOct2012.pdf
- The Passivhaus Standard. Available at http://www.passivhaus.org.uk/standard.jsp?id=122
- Passivhaus Trust. What is passivhaus. Available at http://www.passivhaustrust.org.uk/what_is_passivhaus.php
- Adopting Passivhaus building standards could allow people to heat their homes using power emitted by their televisions. Available at http://www.independent.co.uk/news/uk/home-news/adopting-passivhaus-building-standards-could-allow-people-to-heat-their-homes-using-power-emitted-by-a6707656.html
- Passivhaus Trust. Camden Passivhaus. Available at http://www.passivhaustrust.org.uk/projects/detail/?cId=14#.Vx1UZPkrJD8