Have the same problem, but the sound is definitely more "whooshing" then just whoosh, it also sound like rushing water in a pipe if that make sense and yes it is rather worrying as it is not normal to me.....Got a chance to talk to the tesla mobile tech who came to do install my gate opener, he told me that there has been a bulletin for this "whooshing" sound issues as more owner are complaining about it. The way he explained it was that now the AC and Heater is in the same system, to generate heat, the compressor work backward so when the freon rush back, it makes that sound. Unfortunately through, there are currently no fix for this issue yet, the tech told me the engineers have make aware of the issue and may try to fudge with the software to fix this.