Les habitants des maisons solaires français de les année 1970 et 1980 revisitées – Une enquête du rapport à long terme entre systèmes techniques et l'utilisateurs

Report, 2005

The aim for the project has been to make a brief post-occupancy survey of solar-homes built in the 1970s and the 1980s in four southern French regions in the neighbourhood of Toulouse: Midi-Pyrénées, Aquitaine, Limousin, and Languedoc-Roussillon. The documentation ‘Habitants de Maison Solaire’, made in 1982 by GRECO and in which data was collected from 172 solar houses at the time, was the staring point for this study. The focus for the survey has not been to make a technical evaluation but to study the occupants of the solar houses and their long-term relation to and experience of a solar energy system. The study is motivated as long-term post-occupancy evaluations and surveys of solar energy systems and the user relation to the system are seldom conducted. In total 51 telephone interviews have been carried through with the actual inhabitants of solar houses from the 1970s and 1980s, a majority of the cases were at the time new built individual villas. The rest of the 172 originally documented cases has been cut out from the study as the owners have not been possible to reach, the projects was never realized or as the owners did not want to co-operate in the study. As a complement to the survey, three solar homes and their inhabitants have been visited. In addition a supplementary interview survey has been made with nine French architects involved in solar homes design in the 1970s and 1980s. Two of these nine architects were visited in their architectural studios. Out of 51 interviews, 35 respondents report that their system is still working and 30 of these respondents find that their system gives a contribution to the energy system. 25 respondents have the impression that they pay less energy bills than comparative households. Of the 34 respondents with systems that still work 28 are satisfied with their system and 25 are still positive to solar energy systems and they would also invest in a solar system today if they would build a new house. Some respondents also report other synergetic effects of the solar house concept such as interesting and original architectural design, a greenhouse that provides a nice living space, and better day lightning due to . 25 of the respondents initiated the idea of a solar house themselves or in co-operation with an architect, one was inspired by a neighbour, and 9 of the respondents say that the idea of a solar house was proposed to them by an architect. 7 of the respondents have systems that only partly work today. Systems that do not function are mainly active systems like solar panels and in one case a solar cell panel. 4 of 7 respondents with non-functioning systems are still positive to solar energy and would make investments in solar energy today. 9 respondents report that their system does not work at all. 7 of these say that the system was proposed to them by the architect. 2 respondents are at least partly satisfied with their investment in a solar system. However, 5 of these respondents are still positive to solar energy and 3 of them would invest in solar energy today. It is interesting to note that 15 respondents did not first want to recognize that they live in a solar house. Of these 15 respondents 9 replied that the system has been removed, only partly works today or was never realised. The remaining 6 respondents say that the system still works but they would not really consider their home a solar house as in many cases the systems consists of passive solar gain. The findings indicates a correlation between functioning systems, an owner initiated solar house and a positive attitude towards solar energy. In the interviews it was noted that inhabitants with a positive attitude towards solar energy and that recognize the importance to invest in renewable energy resources are more likely to make efforts to make their system work (the older solar houses often have rather demanding system that needs daily manoeuvres). The respondents that have a positive attitude to solar energy and have chosen to keep their solar system also seem prepared to accept a less comfortable indoor climate. A surprisingly large number of the solar houses are still working today. It is not that surprising that low-tech systems such as green houses and direct solar gain still work also due to the fact that these ‘systems’ give other living qualities like extra green rooms and day lightning. An interesting finding from this study is that a larger number than expected of solar panels are still working today, with minor or larger changes, (16 out of originally 25). Also the majority of the Trombe walls are still in use today (10 out of 17). The fact that a large number of the studied solar houses still function today despite that many systems are in-efficient and demand regular maintenance can probably also to some extent be explained by the fact that these houses are privately owned. To change the original design and heating systems involves large costs for the owner.