10 thoughts on “A Quiet Air Conditioner”

  1. You get a ‘smart’ AC unit, and one day your betters in California will decide that it is not ecologically supportable and fry it.

  2. Inverter AC’s need a processor anyway to synthesize the variable-speed 3-phase drive for the compressor. (The variable inverter drive is what makes them so efficient; it can continuously match compressor drive to the cooling requirement.) So yeah, I haven’t seen one yet where they could resist the urge to add some degree of fancy whiz-bang “smart” features. But you generally have the option to ignore all that and just set a temperature for it to keep.

    I expect with this one you’re mainly paying more for the engineering that went into how quiet it is for a window unit. NB – you can get similar quiet in most any “split unit” since the compressor-condenser is outdoors. The cheapest are a bit more money but also do a bit more cooling, 12,000 btu/hr versus this one’s 9000. Possibly worth it if you have more than one room you want to cool. (A lot of them are also DIY-installable, with set-length coolant lines precharged – get everything bolted in place, run the lines from the indoor to the outdoor unit, hook them up, then open a one-time seal to release the coolant and activate things.)

    1. All we need is to cool the master bedroom, a few days a year. If we can do that quietly, while not giving Sacramento the option of shutting it off, we’re good.

      1. In theory, not giving Sacramento the option of shutting it off when you need it most should be like keeping a “smart” TV from spying on you – just never ever EVER give it the password to any local wireless network.

        In theory. I suspect a gray market in physically excising wireless comms capability from “smart” appliances will develop at some point.

  3. I was more interested in the dual inverter. After wading through a couple of fairly stupid reviews, it looks like one inverter driving a two speed poly-phase motor.

    I wonder how much of the quietness comes from substituting a, probably 3 phase, motor for the usual permanent split capacitor motor. They always have some noise from the capacitor phase lag. Obviously, being able to run the compressor slower is probably most of it.

    Inverter drives are starting to be attractive for small variable speed applications instead of DC. They’ve been using them in washing machines for some time.

    The smart part probably makes it cheaper since they can offset part of the cost by selling data. I can’t quite see how that would be valuable but it is a thing.

    1. Or, a second lower power inverter to reduce idle-current draw at lower compressor power settings? You’re right, it’s very hard to tell what’s actually going inside these things from the marketing blurbs and technoramus reviews.

      1. ..or a second inverter to drive a variable-speed ventilation fan, which would in fact tie the second inverter to the quietness as the marketing bumf alleges. I’d bet that’s it.

        1. I hadn’t thought of that. On a widow sized unit, the blower is usually driven by a small shaded pole motor that can be controlled with a resistor. not too efficient, but the power is a few tens of watts. They’re also quiet.

          Processors have become powerful enough that you could probably just add a second set of power electronics controlled by the same processor. Especially for a small motor, it could be pretty cheap.

          A lot of the complication of an inverter drive is to handle dynamic loads. Both of these would be pretty steady. It’s the sort of thing you can do when you are planning on tens of thousands of units. You can make exactly what you want instead of having to choose from a catalog.

          Tesla was right, an induction motor is about the best invention of the last 150 years.

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