Wacker Chemie AG Hanns-Seidel-Platz 4 81737 München, Germany www.wacker.com FEATURE Number 2, August 2010 Climate Protection: Innovative Construction Chemistry Increases Energy Efficiency Greenhouse gas emissions can only be limited if energy is used more efficiently than it has been to date. Home heating, air conditioning and hot water account for the lion s share of private energy consumption. This is unlikely to change in the near future, since nobody wants to make do without hot water and comfortable living, nor should they have to. Nevertheless, there are ways to reduce domestic energy demand. In recent years, the construction and chemical industries have developed innovative technologies and products that contribute significantly to increased energy efficiency. Energy-efficient exterior insulation and finish systems (EIFS) and water-repellent insulating materials impregnated with silicone products reduce heat loss in the home and lead to a drastic reduction in heating costs. Silicone resin emulsion paints also help conserve energy because they keep exterior walls dry and thus preserve the insulating effect of the masonry. Reducing energy costs by 60% The failure of the Copenhagen summit on climate change has emphasized the need for concrete measures to protect our climate: only if all efficiency potentials are utilized and all energy-saving technologies are applied can there be any hope of confronting climate change. Practical climate protection translates directly into cost savings, especially in winter, as oil and natural gas prices go up during periods of bitter cold. Suitable thermal insulation could help not only to improve the interior climate, but it could also slash energy
Page 2 of 12 80% savings on heating energy by renovation 63 megatons of CO 2 less per year from 2020 costs by up to 60%. This, in turn, would substantially reduce CO 2 emissions. There is still significant scope for reducing energy requirements for homes and other buildings all over the world. In Germany, the highest potential energy savings can be achieved in existing buildings. According to the German Energy Agency dena, these buildings require about three times as much energy to heat as newly constructed buildings. Dena s data indicate that heating and hot water account for approximately 87% of total energy requirements in private households. Interior heating accounts for the largest share of this (75%), approximately 70% of which escapes through the roof, exterior walls and basement. According to dena, up to 80% of this could be saved by proper renovation and modern construction technology. The Energiekompass 2009 study produced by the German EIFS trade association (FV WDVS) shows that energy efficiency measures in existing buildings alone could save five times the energy fed into the grid by all of Germany s nuclear power plants in 2007. According to the FV WDVS, about 450,000 buildings would have to be upgraded in terms of energy efficiency every year to meet the climate targets set by the German Federal Government. From 2020 on, CO 2 emissions could be reduced by 63 megatons per year solely through measures that pay for themselves. According to the trade association s study, this means that the cost of these investments can be recovered by the resulting energy savings alone. FV WDVS has calculated that home heating costs of
Page 3 of 12 Upgrading reduces heating costs by 50% Potential savings through energy efficiency: 700 terawatt-hours Saving 65,000 liters of crude oil with EIFS German households have almost doubled in the past ten years. Based on the assumption that prices will increase by an average of five percent per year, the cost of heating a onefamily house using around 3,000 liters of home heating oil per year will add up to approximately 80,000 in the next 20 years. According to the trade association, insulating exterior walls and replacing the heating system would save approximately 50% of energy costs. Prof. Gerd Hauser at the Technical University of Munich also considers increased energy efficiency of buildings to be one of the most important steps: If existing buildings were renovated for energy efficiency in such a way as to achieve the technically possible 35% reduction in consumption, this would result in potential primary-energy savings of 700 terawatt-hours. In other words, the energy that could be saved through measures to improve energy efficiency exceeds the potential of renewable energy sources by a factor of ten. EIFS are the simplest and most reliable method of preventing energy loss. Independent studies calculated the long-term effect of an EIFS in a typical one-family or duplex house with 24-cm walls. It was found that over a period of 40 years, the annual energy consumption could be slashed from roughly 24,200 kwh to 9,600 kwh. Seen over the entire period, this is equivalent to a saving of about 65,000 liters of crude oil. With that amount of fuel, a car could travel an average of 830,000 km. EIFS were originally used primarily to reduce winter heating costs in the cooler regions of Europe. Since then,
Page 4 of 12 Efficiently warding off heat in warm regions Good bonding is paramount for insulating capacity they have become increasingly popular in other regions with different climates as well, explains Dr. Stefan Ingrisch, technical service manager for Construction Polymers at WACKER. The better a building is insulated, the less energy is needed to create a permanently comfortable interior climate regardless of whether the building needs to be heated or cooled. A facade covered with an EIFS wards off heat very efficiently, states the construction expert. Applied to the outside of a building, the insulation prevents unnecessary heating of exterior walls during the hottest days of summer. In addition, EIFS reduce temperature differences between the indoor air and the wall surfaces, thereby greatly improving the comfort level inside. EIFS can be incorporated in the design of new buildings right from the start and they can be applied to old buildings under renovation. EIFS consist of a multi-layered material composite, the various components of which each perform a different task. The most important thing is that they bond well to the substrate. Mineral-based mortars by themselves don t actually adhere to modern insulation materials like styrofoam at all. A firm bond to the insulating material, resulting in a permanently stable insulation system, can be achieved only by the addition of specialized dispersible polymer powders such as VINNAPAS. Just two to three percent of VINNAPAS in the mortar is sufficient for creating a durable and stable bond between the polystyrene board and the adhesive respectively embedding mortar, explains Dr. Ingrisch. This, by the way, is true for improved adhesion
Page 5 of 12 Perfect bonding to any substrate Exterior insulation is not always possible in the preservation of historic buildings to all substrates, be they concrete, brickwork or wood. Starting from the wall, the first EIFS layer is an adhesive mortar modified with VINNAPAS polymer powder. The mortar levels irregularities in the substrate and creates a stable bond between insulation board and wall. This bonding layer is followed by the thermal insulation board, which may be made of rigid polystyrene foam or other materials. A reinforcing layer consisting of the embedding mortar with added VINNAPAS polymer powder is then applied to the insulation board. The polymer powder allows the mortar to adhere to the insulation board and gives it flexibility to cope with mechanical stress. A glass fiber mesh is incorporated into the embedding mortar, which provides additional stability and protection from impact and weathering. The outermost layer is a decorative plaster or a paint coat. Exterior insulation and finish systems are therefore ideal for anyone looking for sustainable energy savings. However, EIFS cannot be used everywhere. Experts have projected that about 43% of existing buildings in Germany cannot be insulated from the outside for various reasons: the buildings may be protected, their facades may be too intricate, or they may contain apartments with different owners who are not prepared to collaborate. Interior insulation measures thus play an increasingly important role as well. Even for insulation materials long in use indoors, innovative technology can improve energy savings still further. For instance, rendering insulation materials such as aerated concrete or mineral wool water-repellent (hydrophobic) saves heating costs. Since damp construction materials insulate
Page 6 of 12 Damp walls are thermal bridges Insulation materials must be dry Water-repellent treatment lowers heating costs far less efficiently, such a measure alone can save a lot of energy and money. The insulating capacity of the materials decreases enormously with moisture. Tests have shown that a moisture content of five percent in a plain brick wall, for example, can lower insulation performance by up to 50%, explains Dr. Daniel Schildbach, technical manager for Construction Chemicals at WACKER. One single square meter of uninsulated damp brickwork leads to twelve extra liters of home heating oil consumed each year. This is caused by the significantly higher thermal conductivity of damp materials. Dry insulation materials have a vast number of air-filled cavities reducing the exchange of heat to a minimum. But if moisture collects in the pores of the material, a lot more heat is transferred than would be possible if the cavities were filled with air. Whereas thermal conductivity in mineral-based construction materials such as aerated concrete increases directly in proportion with the water content, thermal conductivity in mineral wool is already increased by very little moisture. According to the industrial standard, insulation materials in Germany may absorb no more than five percent moisture in theory, that is. In practice, however, this level is often exceeded. On construction sites, insulation materials are often left unprotected and exposed to moisture. Because of such improper storage, the reference values measured under dry conditions are greatly exceeded, continues Dr. Schildbach. Left untreated, perlite or mineral wool can absorb large amounts of moisture, in some cases up to nine times their own weight. Such water reservoirs in the wall will later lead to mold formation and
Page 7 of 12 Mineral wool that floats on water salt efflorescence in the home, and even to frost cracks in extreme cases. To prevent this, many manufacturers choose to make their insulation materials water-repellent. In this way, the glass wool retains its insulating capacity even if it is not stored properly in a dry place prior to use. In addition, water vapor can get out, but liquid water cannot penetrate indoors. Experts at WACKER have developed a range of specialized silicone emulsions, sold under the name SILRES BS, to make insulation materials hydrophobic. These emulsions are free of solvents and can be diluted with water; they align with the surface layer and make it water-repellent. The functional siloxanes used have a high substrate activity and quickly spread out into layers of molecular dimensions. The active siloxane s hydrophobic methyl groups bring about the distinct beading effect and inhibit the penetration of water into the insulation boards. Dr. Schildbach explains hydrophobization by way of an impressive example: Mineral-wool insulation boards treated with SILRES float on water, even after 24 hours. The water absorption of aerated concrete can also be reduced by up to 70% with SILRES. When treated with water-repellent additives from WACKER, these insulation materials help to save energy. They contribute to a reduction in CO 2 emissions and provide a more comfortable indoor climate. In addition, they contribute to a more sustainable use of construction materials as regards longevity and durability. For us, sustainability also means enabling effective protection against improper treatment, says Dr. Schildbach. SILRES also helps to reduce CO 2 emissions in quite a
Page 8 of 12 Hydrophobization lowers CO 2 emissions in brick production Silicone resin emulsion paints assist thermal insulation different way. An example is the production of clay bricks, in which the density, and thus the quality, is specifically governed by the firing temperature. Lowering the firing temperature can save energy and reduce greenhouse gas emissions, explains Udo Goedecke, marketing manager for Construction Chemicals at WACKER. This is of particular interest for the largest brick market in the world: India. Most of the manufacturing facilities there do not have energy-efficient high-tech furnaces, says Goedecke. Energy savings can be achieved if the bricks are fired at lower temperatures and then rendered water-repellent. For the silicone to penetrate into the pores sufficiently deeply, the bricks must be briefly sprayed with a mixture of water and SILRES BS 16. SILRES BS products are also used on exterior walls to deliver energy savings, since not all facades are suitable for fitting complete EIF systems. In such cases, silicone resin emulsion paints can help to reduce heat loss. Silicone resin emulsion paints keep facades dry for longer and are therefore ideal for supporting all measures for insulating exterior walls, explains Nadine Abt, marketing expert for Construction Silicones at WACKER. Research conducted at the Fraunhofer Institute of Building Physics in Holzkirchen, Germany, supports this statement. This research involved calculating the effect of water uptake and diffusion resistance in one-family houses, i.e. the ratio of heat loss to moisture content of the masonry. The result was that modern silicone resin emulsion paints can reduce heat loss of an unprotected facade by as much as 40%. This may also have a significant effect on the total energy balance of a house. Just
Page 9 of 12 Waterproof and breathable thanks to silicone resin Preservationists go for silicone resin emulsion paints rendering a facade water-repellent can reduce the total heatingenergy consumption of a house by an average of 4.6%. That means there is a high potential for savings in a relatively simple measure, namely using the right paint for one s house. Thanks to their silicone resin network, such paints are not just highly water-repellent, they also permit diffusion. They form a layer on the facade that is both hydrophobic and water-vapor permeable. It would be quite appropriate to compare a coat of silicone resin emulsion paint to the way modern sportswear works, explains Regine Köcher, marketing manager for Construction Chemicals at WACKER. The hydrophobic yet breathable effect of a silicone resin coating also ensures that damp masonry dries more quickly, since no new moisture can penetrate. Studies have shown that after just one year, damp walls coated with silicone resin contain up to ten percent less moisture. That results in increased insulating capacity, Just like a dry sweater keeps you warmer than a wet one, says Köcher. All these advantages are especially significant where the use of EIFS is undesirable or impossible, as in the case of old, protected buildings. For such buildings, silicone resin emulsion paints are one of the few methods that can be used to improve the energy balance. In Germany alone, there are a million halftimbered buildings; experts believe that the use of silicone resin emulsion paints offers huge potential energy savings for these buildings. For economic reasons, historic preservation offices increasingly opt for silicone resin emulsion paints, says Köcher, citing well-known examples such as Neuschwanstein castle near Füssen (Germany), the Kremlin palace in Moscow (Russia) and
Page 10 of 12 Good ecobalance with silicone resin emulsion paints the Ponte Vecchio in Florence (Italy). In silicone resin emulsion paints (SREP ), the silicone resin acts as a binder. The facade paint additionally contains a polymer dispersion that bonds the fillers and pigments together. The silicone resin coats all the particles with a very thin, closed film, which, among other things, makes the coat hydrophobic. Silicone resin emulsion paints thus reduce heating costs, which also benefits the environment. They contribute decisively toward a more cost-effective, greener energy balance for buildings. Illustrations Most of the indoor heat of a building escapes through the roof, exterior walls and basement. According to the German Energy Agency (dena), as much as 80% of this heat loss could be prevented by proper renovation and modern construction technology. (Illustration: Wacker Chemie AG).
Page 11 of 12 Modern EIFS for building insulation consist of a multi-layered material composite. But only the addition of a dispersible polymer powder creates a firm bond to the insulating material and thus a permanently stable insulation system (illustration: Wacker Chemie AG). Due to rising energy costs, energy-saving measures in buildings are gaining in importance both in newly constructed and existing buildings. According to the German Energy Agency (dena), building insulation using EIFS, for example, offers the highest potential for savings (chart: Wacker Chemie AG).
Page 12 of 12 The insulating characteristics of damp insulation materials are far inferior to those of dry ones. It is therefore important to protect insulation materials against moisture. Treatment with SILRES silicone products from WACKER provides that effective protection. These silicones are highly water-repellent and prevent moisture from penetrating into the material (see drop test). This ensures maximum insulation performance of the material (illustration: Wacker Chemie AG). Note: Photos are available for download at http://www.wacker.com/pressreleases For further information, please contact: Wacker Chemie AG Media Relations and Information Florian Degenhart Tel. +49 89 6279-1601 Fax +49 89 6279-2877 florian.degenhart@wacker.com