We're building in SE Melbourne and we are having the builder install add-on refrigerated cooling during construction. The house is 52 squares double storey - actual living area is less as that includes double garage. The original spec for the cooling unit is an Actron SRA190C/SRA190A 18kw on 3 phase power with Bonaire B430|XA, 4 star efficiency, gas ducted heating unit. The heating unit was upgraded to the 4-star B430/XA unit because of it's higher air flow. We have 21 outlets throughout the house. It is only zoned for two zones; downstairs and upstairs and we've been advised that when running the cooling to only have either zone 1 or zone 2 on but not both at once. Heating is fine to run both zones at once.
The external AC unit was installed yesterday, and it's model is SRA230 and it's cooling output is 23kw. I even climbed in the roof space to check the matching component and sure enough it's the same. Now I'm wondering why the larger unit was installed? Of course never look a gift-horse in the mouth and I think this is a bonus (I'm not saying nuthin' to the builder), but does this mean we could probably run cooling now to both zones? Any downside to the larger unit running as an add-on to the Bonaire Gas Heating?