Hisar-Rooftop-solar panel – Prices of solar PV systems offered by various vendors can differ significantly. It have several reasons for the variations of prices, such as
Overstatement of capacity – Some vendors advice a rooftop system with 1 KW modules (solar panels) and a 5 kW inverter as a 5 KW system. As the electricity is generated by the modules this system only has a 1 kW capacity and the price offered by the vendor should be compared with other 1 KW systems and not 5 kW solar plants.
Brands – Products from Branded or Gov. Authorised  manufacturers are typically more expensive but offer much better performance and reliable.
Certifications/Standards – Products that are certified and meet quality standards are more expensive.
Warranties – The prices of the system can depend on the warranties offered.
PV Modules – Industry standard warranty is 5-year manufacturer warranty 0-10 years for 90% of the rated output power 10-25 years for 80% of the rated output power.
Other systems – Inverters, Galvanised mounting structures, cables, junction boxes, etc. typically come with a 1 year manufacturer warranty which can be extended to 5 years