Generally when you cover your AC unit, you want to cover it at the end of the summer and the beginning of the fall. Then you can keep it covered all throughout the winter.
The reason for this is to keep out leaves, nuts, snow, ice, and general debris from the colder months. Snow can damage your AC unit by breaking the fan blades and insulating the unit, causing it to overheat. Leaves can accumulate inside of the unit and cause it to retain moisture, which contributes to corrosion of the unit.
When you cover your unit, use a breathable material so that air can flow freely through the cover, allowing the unit to continue to operate correctly. Never use plastic, as it will keep the unit insulated and not allow it to cool and heat properly.
When you cover it, only cover the top and the top six inches of the sides. This will protect the most vulnerable part of the unit, while keeping out the unwelcome wear and tear. If you want a more permanent solution, consider building a small pavilion over your unit. This will eliminate the need to add and remove a cover each season.
If you are having issues with your heater or AC unit, please reach out to us at Acme AC, as we have 24-hour emergency assistance.