Fujitsu vs Mitsubishi
I currently have a 10 year old Fujitsu multi-zone ducted system cooling my 2nd floor (the first floor is cooled with a combination of ductless heads from a separate outdoor unit).
The outdoor unit is an AOU36RML1 (36k BTU) and is joined to a 12k ducted unit in the upper attic that cools two bedrooms and two 12k ducted units in the kneewall, which cools a finished attic area (they are both controlled by the same thermostat and each are ducted to two registers that are all in a line about 25 ft long via flex duct).
The outdoor unit crapped out, so I’m looking to replace the whole system. My cooling load appears to be about 13k in the zone currently cooled by the two 12k units and 10-11k for the two bedroom zone.
So, I think I can pretty clearly get away with a smaller system, either the AOU24RLXZ (likely with 18k and 9k indoor units) or the MZX-3C24NA (15k and 12k indoor units). I have quotes from a couple contractors who get good ratings – $10k for the Fujitsu system and $11.5k for the Mitsubishi system. Wondering what you would recommend – is Mitsubishi still considered superior in quality to Fujitsu? Will one system be more efficient? It’s not clear to me whether the indoor units for these multi-zoned ducted systems have turn-down capability like with the single-zone systems or if they are just on-off, in which case I imagine the Mitsubishi that is able to fit the load a little closer might be better.
Another question is, will the smaller blower on the Mitsubishi units be a problem here? 25 ft with flex duct covering 4 registers seems like it might be on the edge of what’s possible. If it turns out the external static pressure is a little too high, how bad of a problem is that? Would the Fujitsu be a safer option, given that it has almost double the static pressure to work with?
I’d love to have been able to put in wall units or ceiling cassettes, but the space doesn’t really accommodate those.
thanks for your thoughts!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part