Paying for it
Cash, or the same job with interest on it
Finance does not make an array cheaper. It moves when you pay and adds a number to the total. Both figures are below on the same install, so the difference is the thing you are actually deciding about.
One job, three ways
A 5.0 kWp install at 8,900 pounds
Representative figures at 9.9 percent APR on an unsecured personal loan. Rates move, and yours depends on your credit file, so treat these as shape rather than as an offer.
Cash
Paid on completion
Five years
60 monthly payments
Ten years
120 monthly payments
All figures in pounds. Brightfell is not a lender and does not receive a commission on introductions; where a customer wants finance we point them at their own bank and stay out of it.
The honest bit
What finance does to the payback figure
Every payback figure on this site is a cash figure. It divides what you paid on day one by what the array saves, and it does not know about interest.
Borrow 8,900 over ten years at 9.9 percent and you pay 14,055, which is 5,155 more than the cash price. That is real money and it lands inside the payback window, so the honest thing to do is add it to the install cost before you run the model.
The calculator lets you do exactly that. Put the total repaid into the install cost field rather than the cash price, and the payback it reports is the one that matches how you actually bought the system.
Try it
Put the total repaid into the model
The calculator takes any install cost you give it. Use the financed total instead of the cash price and watch what happens to the second figure.