Before we get into the technical explanation of how to arrive at cost, we can save you some reading time. There is a current rule of thumb today on how much a solar system should cost in Orange County after the size has been properly determined. You take the size of the system in DC watts and multiply it by $4.50 and that will get you really close.
Now, lets look at the exact figures in determining your cost.
Power demand is how much energy you use per year and this is typically measured in kilowatt hours.
Then, how much you pay for those kilowatt hours is really important. Not everyone pays the same amount per kilowatt.
Also, the time of day you use your power matters. There are different rates for different times of the day. If you are with SDG&E for example and using power during business hours then you will pay up to four times more for that power than what you would for the rest of the day. This is a good lead into sizing.
Sizing will be different for each person’s individual needs. You may think- my neighbor has the same size house and same size bill just like mine and he just installed a system for $18,000 after rebates. So, my system will cost the same. Not exactly, what if your family is gone during the day and you neighbor works from home and his wife is also home with their baby? Two different scenarios two different size systems. Your system will be smaller and cost much less because of what you are paying for power compared to your neighbor.
Solar fraction is something that will differ among different property owners. Solar fraction is simply the percentage of your power bill you want to eliminate with your solar system. Some people want to offset the most expensive charges on their bill which might be 75%, while others want to wipe out their bill all together which would be 100%. These different scenarios will require different size systems.
The next factor is your type of roofing material. If you have a tile roof then there will be an extra cost involved for the labor in moving those tiles when installing a solar system. Composite shingle roofs don’t require extra care when installing. Another factor is if your system would be ground mounted. A ground mounted system will involve more labor and materials than a roof mounted system.
The last thing we want to look at is what geographic concerns are there? Different areas have different challenges and benefits. Is your house coastal and affected by the marine layer? Are you far inland and have temperatures over 100 degrees? Are you in the desert that has a lot of dust collection? These factors will determine not only size modifications but also type of panel used.
Your solar professional should take all these factors into consideration and come up with the size system that meets your individual needs. Once you have the right size system you can then compare price. That is when you divide the total cost before rebates by the watts installed. You should come up with a figure around $4.50. That is how much your system should cost.
We would also like to welcome any questions and concerns you might have along the way. We would love the feedback! Just email us on our contact page and we will answer your concerns within 24 hours.