Consider  an  air-conditioning  unit  in  your  home  operating  in  heating  mode  during  cold  months  in  Melbourne  (i.e.,  June-September).  The  unit  is  used  to  maintain  the  indoor 
temperature at  a comfort level (your reasonable assumption).  How  much can be  saved  on  electricity  cost  during  this  period  (roughly),  if  the  system  is  converted  to  a  ground 
source heat pump? 
 
Assume the following ones and make any other assumptions as required to answer this 
question: 
 
• The power of the heat pump unit  
• Number of operating hours per day 
• Your comfort temperature level 
• Average outside temperatures for months June to Sept., during the hours that the 
unit operates 
• Cost of electricity (per kWh) on your contract 
• Keep the cost of system’s alteration outside your calculations