The only reason I can see for 25K BTU in a 300 sq ft room is if one wanted the room to be a sauna.

Switch the wall units would involve:

- Removing refrigerant from the whole system.

- Disconnecting/dismounting the wall units from the refrigerant lines and re-installing in alternate locations.

- Reconnecting refrigerant lines and recharging the refrigerant system.

Have the contractor do the switching of units. It's the only long-term proper solution.

The capacity of each unit needs to be appropriate to the heating and cooling loads of the space(s) it conditions. The air handlers will need to be swapped. As for what's involved behind the walls-- the answer depends on whether the diameter of the the two line sets is the same. In any case, the contractor screwed up big time and it's on them to fix the problem properly.

Thanks! I think diameter of the sets are different so sounds like it may involve going into the walls to redo... Wish there was an easier fix.