Amortization Calculator

SHES Amortization Calculator

This online cal­cu­la­tor allows you to esti­mate the return on invest (ROI) time of a SHES sys­tem with­out grid feed-in for mul­ti-unit res­i­den­tial and office build­ings.

The cal­cu­la­tor is not suit­able for busi­ness parks, as ten­ants there have very dif­fer­ent con­sump­tion pat­terns.

ATTENTION! The result can only be a guide­line; the spe­cif­ic val­ues depend on the build­ing’s loca­tion, how and at what cost the pho­to­volta­ic sys­tem can be installed. Furthermore, prices for bat­tery stor­age, etc., are sub­ject to fluc­tu­a­tions. The prices used as the basis for the cal­cu­la­tion were last updat­ed in December 2025.



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Explanations
  • Apartments with low ener­gy con­sump­tion dur­ing the day require a larg­er bat­tery stor­age unit so that the elec­tric­i­ty gen­er­at­ed dur­ing the day is avail­able in the evening.
  • For apart­ments with air con­di­tion­ing or offices, the ener­gy con­sump­tion dur­ing the day is high enough that a small­er bat­tery stor­age unit can be used.
  • Offices con­sume the elec­tric­i­ty direct­ly when it is gen­er­at­ed.
Assumptions
  • No ener­gy is fed into the grid. Grid feed-in is, how­ev­er, pos­si­ble in prin­ci­ple; please con­sult us for advice on this.
  • Every SHES sys­tem includes a bat­tery stor­age unit. For apart­ments with­out air con­di­tion­ing, a bat­tery capac­i­ty of 2 kWh per ten­ant is planned; oth­er­wise, 1 kWh per ten­ant. In prac­tice, we dimen­sion the capac­i­ty based on the ten­ants’ actu­al con­sump­tion.
  • The pho­to­volta­ic sys­tem gen­er­ates each month the ener­gy out­put per kWp as mea­sured on aver­age in Berlin for the years 2020–2023. Source: PV-GIS, pro­vid­ed by the EU.
  • The ener­gy con­sump­tion is approx­i­mate­ly the same every month.
  • All ten­ants have a sim­i­lar­ly high ener­gy con­sump­tion (max­i­mum dif­fer­ence by a fac­tor of 2).