Ducted vs. ductless minisplit and silence
I’m trying to get to the most silent A/C in a small 1200 sq ft house (old construction) and am zeroing in on a mini-split system (prob 1x 15k-18kBTU and 1x 9k). I have a 2007 vintage Mitsubishi MSZ09UN wall-mount in a studio and while it’s quiet it’s not very quiet, e.g., when sitting reading or working silently it gets to our nerves after a while. That unit is rated 22dBA on low. I’m looking for quieter…
Looking at the engineering manual for the MItsubishi slim duct units I see that at first glance they seem to be louder, for example, rated at 23 and 30dBA for the 12k vs. 15k units (SEZ-KD12NA4R1.TH and 15 variant). But then I look at the engineering manual, and I see that for wall mounted units the sound measurement is taken approx 1m down and 1m in front of the unit, i.e., in the direct air flow, while for the ducted units it’s taken 1.5m straight under the unit, i.e., away from the airflow. That makes it a bit of an apples vs oranges comparison, plus presumably the ducted unit sits on top of a soffit or ceiling.
Does anyone have experience with the noise level that can be achieved by the ducted vs ductless units?
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