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Low-energy House (BBC Effinergie house)
What is a low-energy house ?A low-energy house (BBC-Bâtiment de basse consommation énergétique) is a building that respects the French law set up by the order of May 8th, 2007 published in the Official Journal (Journal Officielle de la Republique Française) of May 15, 2007 which specifies that for the new residential constructions, the objective of maximal consumption in primary energy is fixed to 50 kWh/m².year - to modulate according to regions and altitude. Taken into account is the consumption of so-called conventional primary energy: heating, cooling, ventilation, auxiliaries, production of domestic hot water and lighting facilities. The BBC Effinergie label is assigned to houses that meet the requirements of the label Low Consumption Building (BBC 2005-Bâtiment de basse consommation énergétique) with the constraint of the airtightness of the building with the obligation to measure the impermeability in the air(1). As for appliances, there are seven classes ranging from economical housing (Class A) with an annual consumption of primary energy for heating, hot water and cooling below 51kWh/m2.year, up to a full energy housing (G). This indicator should be complemented by a breakdown between renewable and fossil fuels and an estimate of the cost in euros, including subscriptions and contributions to global warming in kg equivalent CO2 m2.year.  To get an idea …Currently, a new home corresponding to the thermal regulations (RT) in France should consume on average of 150kWh/m² for primary energy. (*) NB: consumption target levels sought by the current thermal regulations and the law of the ‘Grenelle Environnement’ (France’s Environmental Round Table) are :
(*) - Things are actually a little more complicated ... In fact, the limit passes to 91kWh/m².year (instead of 150kWh/m².year) by use of fossil fuels (oil or gas). On the other hand all kW of electricity consumed is multiplied by 2.58. Indeed we consider that 2.58 kW of primary energy are needed to produce 1kW of energy for the final consumer. How to obtain this level of performance ?
Which are problems to be handled to reach the thermal performances of a low-energy house ?Average distributions of the energy decreases in a new individual house :
A suitable and seamless insulation :
Controlled ventilation performance :A specific and pushed treatment for the summer comfort :If one saves energy in winter the point is not to spend it for summer cooling. It is to design an inexpensive and flexible summer ventilation strategy to manage the inertia of the building. Good airtightness :Being in the framework of a building with a very high energy performance, induced losses by air leaks at wall connections, coffered shutters, window frames, punctures made for networks and sheaths (electricity, ventilation) ... become significant. It is therefore very important to pay a particular attention to these singular points. In addition to obtaining the BBC Effinergie label (Low consumption label) a very low level of natural renewal of air is required. The infiltration test should not exceed 0.6 vol/h under 50 Pa which corresponds to 0.03 vol/h under normal conditions Use of renewable energies :
Reducing the electricity consumption for lighting :By facilitating the natural lighting and considering energy-saving lamps. Relying on the right person to pilot the construction of a low-energy house.
Useful links :
Foire aux questions
What is an ecological construction ?
Low-energy House (BBC) Passive House Bioclimatic Architecture RT2005 High Energy Performance Label HPE & EnR Label BBC Effinergie® Label Energy-plus Building HQE® Approach Wood Construction Timber Framing External Insulation Mechanical Ventilation Ground-coupled Heat Exchanger Natural Ventilation Renewable Energy Geothermal Power ECS Solar Panels Photovoltaic Electricity Wind Turbine Cellulose Wadding Hemp Wood Fiber Straw Energy Performance Certificate Carbon Assessment Passive Building (BEPAS)
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