What was the investment in my Heat Pump Project?

I described almost everything but forgot to describe the most important :-). What was the investment actually? The majority of investment represents the vertical geothermal collector. One meter of geothermal collector (drilling + installing + testing + material) cost me about 50 Euro. Nowadays the price is higher. I have 220 meters of geothermal collector so it cost me about 11.000 Euro. Another high investment is heat pump, it cost me 3100 Euro. The total investment was 16.500 Euro.

Geothermal Collector = 11.000 Euro
Heat pump = 3.100 Euro
Water heater + pumps = 600 Euro
Pipes, valves, heat exchanger, other work = 1.800

I also received a subsidy of 2000 Euro for installing high efficiency heating system using renewable resource. So my investment was actually 14.500 Euro. If I would install oil furnace instead of heat pump the investment would be of course lower, but the operational costs would be higher (3 to four times higher). According to my calculations and simulations the cumulative costs (investment + operational costs (electricity)) of my heat pump would met the cumulative costs of oil furnace (investments + operational costs (oil + electicity)) in approximately 10 years. See also the Graph. This is I think called return of investment in 10 years – but I’m not economist so please excuse me.