Hello JHW
Just a word of warning
The outdoor air con unit is fitted in the utility room, this is the incorrect location for the unit from day one due to inadequate ventilation in and out of the small window hence in cooling mode the compressor overheats, the owners do not know this unless they attach a lap top computer and read the information on the screen, also the output temperatures of the indoor units are not low enough to keep the rooms at the correct temperatures.
In the heating mode the system goes to defrost mode more often than it should so the heating from the indoor unit stops when unnecessary. Also when the system is heating the heat output of the indoor units is lower than should be to keep the rooms warm enough.
So putting the windows in will make this even worse and cause reduction to the life of the compressor and inverter system. There also have been cases of the inverter systems catching fire or exploding.
If you really have to put in the windows make sure you can lift the glass panels out for when you run the air con as most of the ones on your site have been fitted too tight to lift out.
all the best
Marucs ACS