Replacing windows with highly insulated units can reduce heat losses to such an extent that solar gains cut heating costs (fig. 8). To minimize unnecessary window opening time and drafts, frame vents can be installed. [11]. Enlarging window openings in walls, when possible, amplifies these savings and admits more daylight. Daylight can also be led into interior spaces by a light pipe [12 + 13].

An example is the renovation of the row houses Kroeven in Roosendaal, the first large — scale passive house renovation project in Holland. Single pane windows were replaced by triple pane glazing in passive house frames.

In addition the walls were insulated with 200 mm XPS and the roof with 360 mm of

cellulose. A new ventilation system was added. A 90% savings in energy consumption resulted, with the annual primary energy for space and water heating being cut from 219 to 21 kWh/m2 [14].

Conclusions

Renovating existing housing can provide living space with superior comfort, very low energy consumption and a special charm. The examples presented here from Austria, Germany, Greece, Italy, the Netherlands and Switzerland demonstrate that it is possible to achieve energy savings up 90 percent, while preserving the special character of the projects. Solar energy is a viable, economic alternative to the costly, last increment of conservation measures in order to achieve the goal of drastically reducing dependency on non-renewable energy and production of CO2. In some of the projects photovoltaic panels were included in the renovation package. When the primary energy value of the solar electricity is deducted from the greatly reduced energy demand for space and water heating, these projects achieve a nearly zero-energy balance.

References

[1] IEA SHC: Renovation Examples, http://www. iea-shc. org/publications/task. aspx? Task=37

[2] Feist, W.: Passivhaus Kriterien, http://www. passivhausprojekte. de/kriterien. php

[3] GAG Ludwigshafen am Rhein Passivhaus im Mietwohnungsbestand: Hoheloogstrafie 1 und 3, WittelsbachstraBe 32, DE-67061 Ludwigshafen, www. gag-lu. de

[4] Calderaro, Valerio: Historic Building in Modena, IT, www. iea-shc. org

[5] Domenig-Meisinger, Ingrid: Passiv House Renovation, Makartstrasse, GIWOG Gemeinnutzige Industrie-Wohnungs-AG Linz http://www. hausderzukunft. at/results. html/id3951

[6] Fehr-Bigger, Hubert, Architekt, Dorfhaldenstrasse 30, CH-8880 Walenstadt Enz, D & Hastings, R.: One-Family House in Walenstadt CH, www. iea-shc. org

[7] Hastings, R. & Morck, O.: Solar Air Systems, Vol. 1 Built Examples, Vol 2 A Design Handbook, Earthscan, London, ISBN 1 873936 85 0 and 1 873936 86 9, www. earthscan. co. uk

[8] Grammer Solar GmbH: Twinsolar, Oskar-von-Miller-Str. 8, DE 92224 Amberg, www. grammer-solar-bau. de

[9] Stickelberger, David: Fakten zur Kostendeckenden Einspeisevergutung KEV fur Solarstrom, Swissolar Infoblat 16.Apr. 2008, www. swissoolar. ch

[10] Enz, D. & Hastings, R.: Apartment Building in Staufen, CH, http://www. iea-shc. org/publications/task. aspx? Task=37

[11] Passivent: Background Ventilation, 2 Brooklands Road, UK-Cheshire M33 3SS, www. passivent. com

[12] Velux: Sun Tunnel Natural Light, VELUX Company Ltd., Woodside Way, UK-Glenrothes Fife KY7 4ND, http://www. velux. co. uk/Products/SUN+TUNNELS/

[13] Glidevale Ltd.: Sunscoop Tublar Roof Lights, 2 Brooklands Road, Cheshire UK-M33 3SS www. glidevale. com

[14] Frank, E. and Bekx, M: Rowhouses, Kroeven in Roosendaal, Holland, Franke Architekten,

Postbus 151, 3360 AD Sliedrecht, Holland, info@frankearchitekten. nl