I have two wall A/C units; one is a (CARRIER) 1992 installation and
the other is a (FRIEDRICH) 2000 installation. Neither unit has ever
been serviced.

Come the time that a unit needs to be replaced, are replacement units
a standard size ? I am concerned about what will be necessary to
ensure that the replacement unit fits the existing hole.

TNX.

Vince
Long Island, NY