An energy efficient building is south facing, integrates passive solar architecture to gain heat (either through an attached greenhouse, double glazing windows or trombe walls) and thermal insulation to retain heat inside the building. The techniques are based on local materials (dung, straw, mud brick) to improve access to reliable, sustainable and affordable energy.
Studies which have been undertaken on energy efficient houses in the Spiti valley have shown that fuel consumption is reduced by 60%, temperatures of rooms in the extreme winters are always above 10°C and the inner air is smokeless. Cold-related illness are reduced and households are able to take on income generating activities such as handicrafts and double their production. Moreover 3.5 tons of CO2 emissions per household is saved annually, which contributes to offsetting emissions and thus mitigating global warming.
The passive solar houses are greatly contributing in improving the lives of the locals in these harsh and cold climatic zones, besides contributing in reducing greenhouse gas emissions.
Ecosphere has built 75 passive solar houses in the Spiti valley and 10 in Lahaul over the last 3 years. These have had a positive demonstration impact on the communities and the government who have shown keen interest in collaborating in expanding the same in the entire region. The technology for the same has been provided by GERES (a French NGO), which specialises in technical innovation on renewable energy. The initiative is also being financially supported by the European Union. Our target is to construct another 250 passive solar structures in Spiti and Lahaul in the year 2010 and 2011.