The payback calculation considers a ZYPHO retail price between 350 € and 550 € added by installation costs. Considers also a household of three people taking shower every day (8’00” each) where the cold-water temp. is 10ºC.  and the shower temp. is 40ºC.

Depending on the country and the system to heat the water, so the cost of energy varies from 0.07 € kWh for natural gas to 0.22 € kWh for electricity. An average cost of € 0.15 kWh was considered.