I am looking to commit to a smart vent system, as I have a house that is pretty unbalanced. It’s not simply about airflow, though that’s definitely part of it, but is also as much about being rooms with more going on in them as far as heat generating sources. Add to this that it’s a 3 story house with multiple open stairwells between floors and well smart vents seem like they would help a lot actually.
I have certain rooms that are always warmer, regardless of heat or AC and there are certainly times of the year when I go from AC to heat and back again many times within a couple month span. So even just being able to statically adjust vents base on mode would be a huge benefit. I have 2 Central AC units and 2 furnaces BTW, and an Ecobee 4 controlling each.
I really thought I was just going to go with the Flairs when I was researching them, they seemed to have a larger percentage of open area, they’re cheaper, had the ability to hardwire them for power, and were metal and more easily printable. I also thought the puck was kinda cool as I have a couple guest bedrooms and to allow guests some control over “their” room was something useful. So wrote Flair with a couple questions, the most important, for me anyway, was I was looking at the Flair DH on here and saw that it was limited to either fully open, half open or fully closed, which seemed really limiting. So I asked if that was a hardware limitation or software, the answer I got back was that half open is no longer supported because it drained the battery too fast.
Hmmm, I guess I don’t really see how a vent that is only either fully open or fully closed can really be all that useful in regulating a homes HVAC system without really screwing with the static pressure. I almost think this almost eliminates Flair outright, unless I don’t really understand how the algorithms work. I can see where during a blower cycle you could vary the airflow somewhat and even close off vents based on some sort of duty cycle so that one zone or more zones are heated or cooled for the full duration at full open while you do some varying restriction on the others, but I guess I don’t see how that can bee really effective if the options are essentially on or off.
So then there is Keen, it’s ZigBee, and I have a strong ZigBee mesh in my house, so that’s good. Apparently it can be directly paired with a SmartThings hub, and with the right DH can use “other” sensors, also a plus, and can be varied by percentage. All good. The down side is Keen seems to use far more of the insert surface area for mechanism, and a poly-carbonate grill which to me looks like it’d be far more restrictive in overall airflow. Also they’re quite a bit more expensive, like 30% more and even if I didn’t have to buy any of the Pucks that I’d have to buy with the Flair system it’s still hundreds more for a fairly large house. I would need 15 vents to do this house, plus a few more at some point. Some of these are oversize which only complicates things since both Flair and Keen only make 4 sizes, though Keen does sell adapters, they are basically just duct reducer plates, reducing a larger opening to a smaller opening and then further reducing that with the mechanism and a grate with what looks like not much more than about 50-60% open area. Poly-Carb is also not so paint friendly.
But I guess the real question is how well do they work, and in particular how well do they work somewhere where I can have some control over them (IE: SmartThings) as I would also like to supplement climate control with ceiling fan control. Also has anyone hacked the Keen vents with maybe battery eliminators to hardwire them in? Since they use 4 AA batteries it seems like you might be able to power them via an adapted USB perhaps. Am I reading too much into the Flairs fully open, fully closed limitation? Are the Keens as airflow restricted as they appear? Anyway not a lot of comparisons between the 2, just a lot of posts in a lot of places complaining about delivery times, though both seem to be shipping at this point.