By Bruno De Wachter / Published on Wed, 2010-05-05 05:30
'Zero energy building' and similar terms
Picture by Ian Britton on FreeFoto.com
You would think that no word has a more unambiguous meaning than 'zero': nothing is nothing. Not so in today’s world of green building. Labels like 'zero energy building', 'nearly zero energy building', and 'zero carbon building' are frequently used, but lack any standardised or official definition. The same can be said of the expression 'bâtiment à énergie positive' that is used in France.
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By Hans De Keulenaer / Published on Fri, 2009-05-08 12:20
A Parliamentary proposal calls for all new buildings to be 'zero energy' by 2019, i.e. to produce as much energy as they consume. The underlying idea is to introduce extreme insulation for buildings, and to provide the remaining energy demand through on-site renewables.
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By David Chapman / Published on Wed, 2008-04-23 18:45
Homes in the UK are responsible for 27% of carbon emissions so improving their environmental performance is very important. Currently, about 170 000 homes are built each year in the UK – about 0.77% of the existing stock – while the number of households expands at a rate of 240 000 households per annum. Although the very high rate of expansion of households is probably temporary, being due to an ageing population, changes in social structure and population movement from new EU states, it is clear that the replacement rate is very low and homes built today will be in use for a very long time.
Two streams of actions are required, addressing standards for new-build and refurbishment measures for existing stock.
For new build, the UK Government has set building construction standards defining a path towards so-called ‘zero carbon’ or ‘zero energy’ homes by 2016. For the present, the ‘Code for Sustainable Homes’ is voluntary for private builders (~75% of the market) but mandatory for public sector housing, housing associations and for homes built on land released by Government.
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By Bruno De Wachter / Published on Thu, 2008-02-07 08:30
UK sets example, will California be next?
The UK is taking the lead in sustainable building. In 2007, new housing regulations were agreed upon and go into full force in stages over the upcoming years. The regulations stipulate that from 2016 on, all new homes in the UK will have to be zero-emission for heating, hot water, cooling, ventilation, and lighting. This corresponds to Level 5 of the Code for Sustainable Homes.
The Code for Sustainable Homes is a new standard that gives new homes a 0 to 6 rating based on their performance against nine sustainability criteria. Level 0 is the base level and means the house meets current regulations. Level 1 includes a 10 per cent energy efficiency improvement over current regulations. Level 6 means a zero-carbon emission house for all energy use. The code was introduced as a voluntary standard in April 2007, and will become a mandatory label in April 2008.
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By Hans De Keulenaer / Published on Sun, 2007-07-22 12:00
What is Building America?Building America is a private/public partnership sponsored by the U.S. Department of Energy that conducts research to find energy-efficient solutions for new and existing housing that can be implemented on a production basis.
What Does Building America Do?
Building America conducts systems engineering research to do the following:
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By Hans De Keulenaer / Published on Sun, 2007-07-22 11:54
As the sixth report in its 'Building America Best Practice Series', the US Department of Energy published a guide on using solar thermal and PV systems (attention: large pdf file!) in combination with good insulation as a best practice for zero-energy homes.
The term 'zero-energy home' is used loosely in the report to mean houses with at least 50% reduced utility bills compared to standard practice.
The combination of energy efficiency with solar is cost effective compared to conventional homes as the reduction in energy bills is larger than the increased mortgage payments from the additional investment. This is a bit misleading though, since insulation will produce the largest part of the cost savings, whereas solar consumes most of the additional investment. Still, it may make sense to a home owner to use part of the cost savings from good insulation to help finance solar technologies.
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By Bruno De Wachter / Published on Mon, 2007-07-16 07:30
Zero-energy houses represent the next generation of dwellings. Their total energy needs are generated on site. Today, residential renewable energy systems are still some years away from being cost effective. Through energy efficiency measures, the overall energy demand of the building can be reduced, thus magnifying the potential of renewable energy to provide a high proportion of the energy demand.
Building low-energy houses
The Building Industry Research Alliance (BIRA), part of the Building America Program, established a Zero Energy House (ZEH) programme. At present, 416 low-energy houses have been built in California alone through this program. Those houses have reduced their grid energy consumption by an average of 51 per cent compared to a standard house. 32 per cent of this savings was realized by energy savings and 19 per cent by a photovoltaic system.
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By Bruno De Wachter / Published on Wed, 2007-06-06 07:30
A growing numbers of U.S. homes off the grid
An estimated 180,000 homes in the U.S. provide their own electricity without connection to the distribution grid. Most of them rely on solar power, although a small percentage makes use of their own wind turbine.
This number is still very small when compared to the total number of homes in the U.S. and not yet of major significance for the power industry. However, it does show that going off-grid is technically feasible, and the number of homes making this choice is increasing by about one third each year.
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