- Jun 25, 2009
- Reaction score
Also, the numbers that the solar company are providing are going to be grossly exaggerated in their favor. I would find someone who has had the same setup for at least a couple of years and ask them, but be prepared to read through the lines- some people don't do numbers very well or they may be hesitant to admit they got duped.
The contractor I used claimed a 5-7 year ROI, but after I reviewed real world output and calculated my own numbers - I calculated a 22.4 year ROI. When I asked how the contractor 'calculated' his numbers - the math was blatantly wrong. I just said 'thanks' and parted ways.
Run your own numbers.
FOR REAL WORLD PV Solar generation numbers - in Oklahoma City:
1) Go here (ht tps://ww w.sunnyportal.co m): SMA Solar Technology AG - Sunny Portal
2) Then click on 'Publicly available PV Systems'
3) Under city enter: oklahoma city
Find and review real-world PV generation. Note the size of the system - and scale it appropriately for your system.
Look for monthly yield (KWh) - then multiply by the KWh electric rate. That's the PV monthly 'savings'.
Now compare monthly savings to your total system expense for (simple ROI).