Payback Period, ROI and NPV — One Client File, Three Answers
- Payback period: when cumulative savings exceed the initial investment.
- ROI: the return on investment over the chosen horizon.
- NPV (net present value): the value of future savings, discounted to today.
Every Assumption Explicit, No Silent Defaults
Investment cost, energy price evolution, discount rate — none of these figures gets silently filled in with a "reasonable default." Every assumption is an explicit input, so a client (or a colleague reopening the file later) sees exactly what the advice rests on.
"Don't Invest" Is a Valid Recommendation, Not a Failure
The goal isn't to present every investment positively. When the numbers come out negative or neutral, that stays visible as the result — an honest final recommendation sometimes also says "wait a bit longer."
Built on the Rest of the File
The final recommendation combines the PV simulation, battery scenarios, and charging strategy from the same client file — not a separate, standalone calculation tool that needs filling in again.