First make sure the outside vent is not open.

I built a nice wooden cabinet to hang over mine. During winter the the
cabinet doors are closed and keep the cold out

"THO" wrote in message
...
Hello,

I have two large air conditioners which are built into our walls at
about head height. Both rooms are cold from the heat loss and
infiltration of cold air. Can anyone suggest the best ways to insulate
air conditioners like these?

Thanks.