However, there are some things that takes into account must be one wants to turn the yield minus not in a thick a photovoltaic system for electricity generation on the roof is a super deal. It is environmentally friendly, produces no CO2, operates silently and the operator money thus. Unfortunately no Ackermannsche 25%, but referred to a twenty-year solid return of approximately 10% p. a. of the invest. Should one believe. So, PV systems partially on old be installed (ancient) roofs that don’t survive the next months and years.

Scenario: A PV system is installed on a roof that has quite a few decades on the hump. After some time, the roof is leaking. In some places, water enters. A normal roof repair cannot be performed. The plant, remove all or part which represents a significant cost factor. After the repair, the system is mounted again.

Very good, all tightly, the line is running. The next winter, the same game. Your roof is leaking. Now thick have the fax and call Her Roofer master, who should look at the disaster. This expires in a few, what drives you, the water in the eyes when you see the cost. Conclusion, the old roof must be down, so also the PV system. Said and done. Photovoltaic system break down, roof according to EnEV (energy one pair Regulation) the very latest 2009 refurbish, install PV system. These costs for dismantling and reconstruction of the plant alone can your yields to zero or even in the deep minus area. Therefore: consult before any construction project on the roof, flat roof, always by the roofer master of their confidence. These can give you information about the durability of the roof and the static load of the roof. Not infrequently, your Roofer master assumes also the assembling of the photovoltaic system. The roofer has experience, because it is his daily workspace. Why do you give your car in a car – repair shop, not a tailoring or butcher’s shop? Jump into the solar industry”many self-proclaimed Experts”around who look at the closer before a few days or weeks still laces, newspapers or vacuum cleaner sale have. Many here only to the sale. Professional consultations, nil. It has spread now among the laity, that nothing may be built on asbestos-containing roofing. And still builds the solar mafia”, despite all prohibitions and set, PV systems in the large handle on sheds and barns with asbestos cement plates. Where no plaintiff, there no judge. But there will be still a rude awakening with safety for contractors and clients. The demolition and renovation far exceeds the yield. Not counting financial penalties.