The economic benefit of a geothermal heating and cooling system is closely tied to the efficiency of the system installed. We use electrical energy to drive the compressor in the heat pump and, to a much more minor extent, to pump the fluid around the ground loop. The less energy we use to create the heating and cooling required the better the efficiency. Two main factors affect this efficiency. The quality and design of the heat pump is a significant factor. This is why we usually use Waterfurnace equipment since it is considered to be among the best if not the best available. But also of great significance is the design of the whole geothermal system. The temperature at which the ground loop fluid enters the heat pump and the temperature of the fluid, either water or air, on the other side of the heat pump significantly affect the efficiency of the heat pump. This is why it is vitally important that the whole system is designed properly. A poorly designed system may heat and cool as required but will use far more electricity than required and so will be far more expensive to run than a well designed system.