They are a simply way to save energy in building, also obtained, in the case of building recovery, by the closing of balconies, terraces, lodges, altanas and similar.
Its functioning is ensured by wide glass surfaces, that allow rays of sun to penetrate into that space and to obtain in this way an augmentation of the heat and of the natural lighting.
This kind of greenhouse brings a lot of different ways of natural energy utilizations; comparing this kind of greenhouse with the classical one made without picking up glass, we notice anyhow that the first one has a drop in energetic consumption. But the peculiarity of this Solar Greenhouse (named also Bio-Climatic Greenhouse), is the particular legislative framework that some Administration subject them.
Unfortunately, if it is not correctly valued, a solar greenhouse can be viewed as only an augmentation of the volume or even as a building abuse that has to be demolished.
In these situations, we have to consider that not every structure is a solar greenhouse with picking up glass, but only the ones faced to south, where, because of the better solar situations, the opaque surfaces stay lighted for a suitable time.
That means that, during a day, the greenhouse has to receive so much light to allow it to warm inside spaces, while reaching the main headline it has been created for: saving energy.
So, the real solar greenhouse, deducting the volume abstractly realized with, is only the one that allows the solar rays to penetrate and obtain light and heat in an efficient way for the headline it has been built for.
The solar greenhouse (and, in effect, everything concerning saving energy), is hardly protected by communitarian, national and regional laws and regulations. In this sense, to respect law, local entity have to supervise on bio constrictions, so that it will always be observed the feasibility and the realization of works that imply energy savings; by this way, many building regulations have been undertaking in a very positive sense.
Public officers who doesn’t supervise on the observation of bio-building or they order the demolition of bio-sustainable works, they can be both administratively and criminally prosecutable.
Pursuant to article 1 of L. 10/1991, eco-sustainable building works are considered as works of public interest, at the same level of ‘undeferrable’ and ‘urgent’ works. At the article 123 of D.P.R. 308/2001 (coming out from article 26 of L. 10/1991), bio-building works do not need a specific authorization, but simply the communication of the starting of the work.
The regional normative, in these last years, has followed that direction, with slenderer procedures, due to promote (both qualitatively and economically) buildings made with the purpose of energy saving.