Efficiency 
				Heating and Cooling Efficiency of Geothermal Heat Pumps
				The heating efficiency of ground-source and water-source heat pumps is indicated by their coefficient of performance (COP), which is the ratio of heat provided in Btu per Btu of energy input. Their cooling efficiency is indicated by the Energy Efficiency Ratio (EER), which is the ratio of the heat removed (in Btu per hour) to the electricity required (in watts) to run the unit. 
			
			
				Economics
				Economics of Geothermal Heat Pumps
					Geothermal heat 
					pumps save money in operating and maintenance costs. While 
					the initial purchase price of a residential GHP system is 
					often higher than that of a comparable gas-fired furnace and 
					central air-conditioning system, it is more efficient, 
					thereby saving money every month. 
			
			
			
				Evaluating
				Evaluating Your Site for a Geothermal Heat Pump
				Because shallow air and ground temperatures are relatively constant throughout the Portugal, geothermal heat pumps (GHPs) can be effectively used almost anywhere. However, the specific geological, hydrological, and spatial characteristics of your land will help your local system supplier/installer determine the best type of ground loop for your site: