Whether you should install rooftop solar or not depends upon a lot of factors, none more so than whether you have a free rooftop with enough space and shadow-free area. Post that it depends on what kind of electricity bills you are generating and what kind of power backup you have. In short this can be a little daunting. This is where Luminous has as come up with a really interesting tool the "SolarizerTM". It is a solar calculator which requires very simple inputs and helps you know your solarisation potential. Using the more advanced version, you can further design the system and also personalise it. Should you need more assistance ask for a call-back or request a site survey.
Installing a rooftop solar PV system is any day a wise choice. It will help you to reduce your monthly electricity bill. But going completely off power from the grid might not be the best thing to do.
Why? If you completely cut-off from grid, then you will be needing batteries for storing the light energy that is converted into electricity. This energy then shall be re-converted for use and it is here that efficiencies of conversion come into play. Also batteries increase cost as they need to be replaced every 4-5 years and require maintenance.
A grid-tied solution with net- metering is perhaps a better choice. You can enjoy all electricity generated by panel during day time and during night time, you can take power from grid.
The math therefore is simple. A system with storage or an off-grid system requires a higher outlay of money owing to the batteries. For complete autonomy an even higher one!
Whereas, with a Grid-tied or an On-grid system you have a choice of power sources your own Solar Power Generation System or the Grid. If you consume more than you generate, you pay for the excess units. On other hand, if you generate more than you "consume" then you get paid for the excess units.
An On-grid solar power generation system with 5 kW capacity would typically cost between Rs. 70/watt to Rs. 80/watt depending on the brands you choose, the balance of system inclusions and the quality of workmanship.
Let's say you consume 1,000 units monthly and your 5 kW system generates about 650 units per month, then your bill will be 350 units only.
The Return on Investment is in around 4.5 years. Then you earn for a minimum of 20 years.