Risk The performance

Risk The performance of water/water heat pumps can be overestimated, especially at the cold climate, since they are only tested at +10°C at the cold side (in reality the ground water temperature can be lower than this). This can also be the case for other ground source heat pumps.  
The degradation coefficient Cc might be a disadvantage for a ground source heat pump when default values are used. Cc =0.9 is a larger degradation of GSHP’s than what is shown in reality. There is a risk that the requirement of having heat pumps tested in part load might lead to extensive laboratory tests, which is costly. It is also difficult to get sufficient data from existing laboratory tests, since few heat pumps are tested in part loads