It wouldn’t hurt if you go a long period without using your air source heat pumps. While you need to pay attention:
1) Drain off water in the heat pump system. Or the unit could be frost damaged when it’s cold.
2) Get your heat pumps covered to keep them clean.
3) Don’t forget to turn off the power.
And more…How to know if refrigerant is not enough in your heat pumps?
Refrigerant is the carrier of thermal in a heat pump system. So if it’s leaked the heat pump will result in performance degradation. Normally a properly installed heat pump has enough refrigerant in the first 3 years. When the heat pump serves for many years, you would need to check if refrigerant need to be supplemented. There’re 4 signals that indicates refrigerant could be not enough:
1) Air discharged from the heat pump is not cold enough;
2) Heating performance is not as good as before;
3) Open the top cap of your heat pump, check the low pressure needle valve using a pressure gauge. Turns out the pressure dropped apparently;
4) There is some oil stain where refrigerant is leaked.
Anyway, it’s a professional job to check refrigerant. So contact after-sale guys and have them supplement refrigerant for you.