Solar Panel Math
Updated: Feb 18, 2020
I’ve done this before but it’s worth sharing again.
We are installing 12 solar panels on a new home soon, so I thought I’d run the numbers again.
12) 290 wall solar panels - $10,000 installed.
30% federal tax credit - <$3,000>
Net investment cost - $7,000
12 x 290 watts per panel = 3480 watts
8 hours sunlight per day average rule of thumb
30 days per month
3480 x 8 x 30 = 835,200 watt hours per month
Or 835 kilowatts saved per month (divide by 1000 to convert to kilowatts)
Winter Park Utilities charges about $0.12 per kwh (kilowatt hour)
OUC charges about $0.11 per kwh
I checked my current and previous utility bills.
834 kilowatts x .11 = $92 savings per month
$92 x 12 months = $1104 per year
Divided by $7,000 investment equals a 15.7% annual return.
Keep in mind that this is actual cost savings or a tax free return.
If you wonder how long solar panels take to pay for themselves, it’s 6.3 years. Then it’s free power.
Or if you look at it from a monthly expense. At today’s interest rates, the $7,000 investment would add about $32 a month to your mortgage payment. So since the solar panels save $92, you’d be wasting $60 per month if you don’t put solar panels on your house.