Efficiency building : Proposal from Isover company part 1

What is energy efficiency?

 The Energy efficiency 

Energy efficiency is a fundamental element in our global fight against climate change. It plays a critical role in minimising the societal and environmental impacts of economic growth in developing and developed nations. Energy efficiency also has a crucial role improving every nation’s security of energy supply. In addition, these benefits can come without a price tag as is the case for insulation where it is easily possible to get five times your investment back in money saved.
Therole of energy efficiency in combating climate change and promoting sustainable development is well understood but it is often forgotten how important this role can be

The Energy Performance of Buildings Directive

Put into action in January 2006, the Energy Performance of Buildings Directive (EPBD) requires all 25 EU countries plus Norway and Switzerland to update their national building codes on a regular basis. Currently (2008), the EPBD is undergoing a revision. This revision is expected to introduce further requirements to the EU member states to enable the EU to reach its goals by ensuring even better energy efficiency in buildings.

The Energy End-use and Energy Services Directive

The Energy End-use and Energy Services Directive (ESD) seeks to reduce the amounts of energy required to deliver energy services to European citizens and businesses. A major part of the savings sought in this directive can be achieved through implementing practical energy saving measures, in particular in new and existing buildings. This directive is intended to facilitate the installation of the cost-effective measures available. Each member state must prepare a national energy efficiency action plan every three years.

For more information: www.buildingsplatform.org

Improving energy performance in EU

* The EU works to improve the overall energy performance of its member states in order to:Tackle climate change
* Face up to the challenge of secure, sustainable and competitive energyMake the European economy a model for sustainable development in the 21st century
*By the year 2020, the EU aims to reduce its CO2 emission by 20% compared to the 1990 level, and to increase energy efficiency by 20%. Two key European directives address the building challenge: the Energy Performance of Buildings Directive (2002/91/EC) and the Energy End-Use Efficiency and Energy Services Directive (2006/32/EC).

What is a very low energy building?

Towards very low energy buildings

Very low energy buildings are designed to provide a significantly higher standard of energy efficiency than the minimum required by national Building Regulations. They are very often designed without traditional heating systems and without active cooling. They result in a saving of energy consumption of 70 to 90% compared to the existing building stock.

Examples of such buildings are: Passiv Haus (Germany), BBC - Bâtiment Basse Consommation - Effinergie (France), “zero” carbon house (UK), Minergie (CH) …

The definition of very low energy buildings varies significantly across Europe. The variation exists in terms of the absolute possible level of energy consumption; the calculation methods and the energy flows included in the requirements vary from country to country…

Most of the official calculation methods deal with the calculation of the primary energy consumption of buildings. However, what processes and how the corresponding energy demand is converted into primary energy differ from country to country. In some cases the primary energy consumption is converted into CO2 emission. The definition and consequently the calculation of primary energy consumption is strongly dependant on the chosen boundary for calculation.

Therefore, direct comparison between the different “standards” is not possible.

Comparison of the energy calculation methods of Minergie and Effiinergie, with the two energy frames as defined in the Passive House standard (total energy consumption and heating consumption per year).

Nevertheless, one thing is common to all of them: they follow the principles of the Trias Energetica. They all require high performing building envelops and reduced energy needs for heating and cooling.
With its unique experience in energy efficiency in the building sector, Saint-Gobain ISOVER is definitely engaged in the promotion of very low energy buildings (new construction and renovation projects). We consider that cost effective technologies already exist that allow achieving (at the building level) very ambitious objectives in terms of reduced energy consumption and low CO2 emissions (under the condition that the previously described principles of the Trias Energetica have been followed).

ISOVER is engaged

We consider that very low energy building standards should become the common rules in all countries before 2020: we push for national building regulations to be improved in this direction.

We also strongly commit ourselves to demonstrate that very low energy constructions and renovations are already technically and economically feasible:

• We have developed the Multi-comfort House concept that we are promoting in all the countries where we are active; the Multi-Comfort House is a very low energy house with enhanced comfort for the occupants ; it can be built under any climate as we have adapted the concept to different climate conditions (moderate, hot and cold climates); we carry out pilot projects in different country: by building locally Multi-comfort Houses, we demonstrate to all the stakeholders in the building chain that dreams can become reality…
  We constantly further improve the thermal performances of our insulation solutions and products to make the design and the construction of very low energy buildings always easier and more cost-effective;*
  
  Moving towards very low energy constructions is a very challenging market transformation for all the partners in the building sector: we invest in promotional and training activities to support those who are starting the “learning curve” to progress quickly down the curve;*
  
  We support national initiatives to develop voluntary certification and labelling schemes for very low energy constructions (PassivHaus in Germany and in Austria, Minergie in Switzerland, Effinergie in France…); we encourage Governments to adopt financial schemes (loans with low interest rates, governmental subsidies, lower taxes…) to make these kinds of buildings more attractive and to turn the voluntary certification schemes into mandatory ones.*

Benefits of low energy buildings

Lower energy bills : owners or occupants of low energy building can keep their energy costs under control and become less vulnerable to future fluctuations of energy prices;
Excellent indoor climate : in a building without draughts, the use of mechanical ventilation flows the air pollutants away and provides fresh air indoor;
Pleasant warmth : both in winter and in summer, large fluctuations in temperature are not practically non existent.
Better acoustical and visual comfort : bioclimatic design and performing insulation of the glazed and opaque wal

How to design and build an energy efficient building?

Energy efficient buildings (new constructions or renovated existing buildings) can be defined as buildings that are designed to provide a significant reduction of the energy need for heating and cooling, independently of the energy and of the equipments that will be chosen to heat or cool the building.

This can be achieved through the following elements

1. bioclimatic architecture: shape and orientation of the building, solar protections, passive solar systems
2. high performing building envelope: thorough insulation, high performing glazing and windows, air-sealed construction, avoidance of thermal bridges
3. high performance controlled ventilation: mechanical insulation, heat recovery

Only when the building has been designed to minimise the energy loss, it makes sense to start looking at the energy source (including renewable energy) and at the heating and cooling equipments. We designate this approach as the Trias Energetica concept.

The trias Energetica Concept

Following the principles of the Trias Energetica concept we have developed the following 5-step approach:

Bioclimatic architecture takes into account climate and environmental conditions to help achieve thermal and visual comfort inside. Bioclimatic design takes into account the local climate to make the best possible use of solar energy and other environmental sources, rather than working against them. Bioclimatic design includes the following principle

The shape of the building has to be compact to reduce the surfaces in contact with the exterior; the building and especially its openings are given an appropriate orientation (preferably towards the south); interior spaces are laid out according to their heating requirements ;*

Appropriate techniques are applied to the external envelope and its openings to protect the building from solar heat in winter as well as in summer; passive solar systems collect solar radiation, acting as “free” heating and lighting systems; the building is protected from the summer sun, primarily by shading but also by the appropriate treatment of the building envelope (i.e. use of reflective colours and surfaces).*

Thermal insulation is a low-cost, widely available, proven technology that begins saving energy and money, and reducing emissions the moment it is installed.

Well installed insulation ensures energy efficiency in every part of the building envelope including ground decks, roofs lofts, walls and facades. It is also well suited for pipes and boilers to reduce the energy loss of a building’s technical installations. Insulation is as relevant in cold regions as in hot ones. In cold/cool regions, insulation keeps a building warm and limits the need for energy for heating whereas in hot/warm regions the same insulation systems keep the heat out and reduce the need for air conditioning.
An exterior wall is well insulated when its thermal resistance (R value) is high, meaning the heat losses through it are small (reduced U value). Insulation is a key component of the wall to achieve a high R value (or a low U value) for the complete wall. The thermal resistance R of the installed insulation products has to be as high as possible.*
To limit the thickness of the insulation within acceptable dimensions, Saint-Gobain Isover constantly improves the thermal conductivity of its materials (lower lambda value) thus allowing increased thermal resistance within the same space.*

Air tightness reduces air leakage – the uncontrolled flow of air through gaps and cracks in the construction (sometimes referred to as infiltration, exfiltration or draughts).

Air leakages need to be reduced as much as possible in order to create efficient, controllable, comfortable, healthy and durable buildings With more stringent building regulations requiring better energy efficiency , air tightness is an increasingly important issue.

Details that are vital to achieving good air tightness need to be identified at early design stage. The next and equally important step is to ensure these details are carried over into the construction phase. Careful attention must be paid to sealing gaps and ensuring the continuity of the air barrier. It is far simpler to design and build an airtight construction than to carry out remedial measures in a draughty home.*
Saint-Gobain Isover has developed systems with innovative accessories that allow appropriate installation of the insulation while guaranteeing excellent air tightness and allowing proper moisture management (see the Vario system presentation).*

Consequences of air leakages : cold outside air may be drawn into the home through gaps in the walls, ground floor and ceiling (infiltration), resulting in cold draughts. In some cases, infiltration can cool the surfaces of elements in the structure, leading to condensation. Warm air leaking out through gaps in the dwelling’s envelope (exfiltration) is a major cause of heat loss and, consequently, wasted energy.
Most existing buildings, even those built recently, are far from being airtight and because of unwanted air infiltration generate huge costs to owners and occupants, in environmental, financial and health terms.
A leaky dwelling will result in higher CO2 emissions. The additional heat loss will mean that a correctly sized heating system may not be able to meet the demand temperature. Draughts and localised cold spots can cause discomfort. In extreme cases, excessive infiltration may make rooms uncomfortably cold during cooler periods. Excessive air leakage can allow damp air to penetrate the building fabric, degrading the structure and reducing the effectiveness of the insulation. Air leakage paths often lead to dust marks on carpets and wall coverings that look unsightly.

Ventilation is the intended and controlled ingress and egress of air through buildings, delivering fresh air, and exhausting stale air through purpose-built ventilators in combination with the designed heating system and humidity control, and the fabric of the building itself.

If you do not insulate properly and ventilate too little, you can risk warm humid air condensing on cold, poorly insulated surfaces which will create moisture that allows for moulds and fungi to grow.*
A controlled ventilation strategy will satisfy the fresh air requirements of an airtight building.*
Air infiltration or opening of the window cannot be considered an acceptable alternative to designed ventilation.*
As the saying goes: ‘build tight, ventilate right.*

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