What does the WWHRS Utilisation Factor mean?

Utilisation Factor explanation

The Utilisation factor accounts for energy losses not included in laboratory testing data but likely to occur in a real-world installation. These are the energy required to warm-up the heat exchanger, any energy left over in the pipe work at the end of the shower and heat losses from the connecting pipework whilst the shower is in operation. 

The utilisation factor for each Recoup WWHRS system can be found on the applicable PCDB Listing