1- 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 Mark 9: The key assessment criteria: Understanding the question Reasonable assumptions Tangible rationale and sensible approach Accurate calculations and results