Some models even adjust the humidity level automatically. Heat Recovery Ventilator systems remove stale air from inside the home, while bringing in fresh air from the outside that is warmed during the transfer process. While it is not necessary to cover a central air conditioning unit, some people prefer to do so. If you are so inclined, please only cover the top. Air needs to circulate through the unit so that moisture will not be trapped inside.
Moisture can cause corrosion on the electrical contacts causing an unwarranted malfunction.
A. Enclosing your furnace is not a problem as long as a few basic rules are followed. The manufacturer puts a label of specifications inside the vestibule of each furnace, included in these are a list of recommended clearances to combustible materials. Another thing to consider when enclosing your furnace is the availability of combustion air. A furnace requires a specific amount of oxygen to mix with the gas for proper combustion. Starving the furnace of that required air could result in incomplete combustion, possibly causing the production of carbon monoxide.