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We would be looking at the Isodrive in the Schweigen, and the twin motor in the Qasair; I gather the Qasair might have the better draw, especially as we will likely have just a short duct (straight up and out), but the Qasair is about $1000 more. If it works better, I'd still get it though, as no point regretting something that doesn't do its job; besides, I gather the Schweigen needs 3m of ducting to be silent, which we may just meet if we kink things.[/quote]
Also make sure you check out the ducting costs on the Qasair before you buy. They are exhorbitant and you must use their ducting.
Noisewise you can hardly hear our Qasair on the lowest setting but turned up to full force you can hear it.