There is nothing necessary. Many homeowners incorrectly believe that it is important to cover the condenser for the winter.
It is not necessary or advisable, to cover and wrap the air conditioning condenser with a tarp or plastic cover during the winter.
The manufacturer designed the condenser unit knowing that it would be outside and exposed to the elements year round.
Wrapping the unit stops air flow from blowing through, this causes a buildup of moisture and condensation on the steel frame which in turn accelerates the rusting process. It may be a good idea to put a piece of plywood or plastic over the top but not the sides of the unit. This would help stop leaves or other debris from entering the unit, but it is not necessary.
Forgetting to remove any cover before turning on the system !
Failure to do so could result in the cover being blown off, causing damage to your property or serious personal injury.
If you cover the condenser we recommend that you remove the fuse or trip the breaker (usually located on the wall beside the unit) to prevent any accidental start up.