See my earlier post here:
The pressure sensors are not really useful under the ST platform for the reasons explained below.
Continuing the discussion from Advice for using one of the compatible thermostats in a dual zone house?:
Continuing the discussion from Keen Smart Home Vents:
Now that’s a good idea. I’ll have to add that to my to do list.
If they put so much analytical work into their hub, then it sounds to me that is worth paying 40 bucks for the hub, just for safety purposes. And still control the vents via ST. Did anyone take their hub for a spin?
i just ordered my stuff with the hub. So will play with both once the arrive at the end of the month.
The temps reported by my vents range from 110F to 127F, so it would be pretty much impossible to relate that to room temperature control…
I asked @NateKeenHome to clarify how the pressure protection worked and this was his response,
The Smart Vent has built-in temperature and pressure sensors that allow
them to track pressure in the system while simultaneously monitoring
your comfort preferences. If pressure exceeds between .5 and 1.2 iwc,
the Smart Vents will open enough to relieve it. We wrote a blog post on
this topic, which you can read here. Given that the sensors are in the Smart Vents themselves, using a SmartThings hub shouldn’t affect this particular feature.
So it sounds like they’re saying no hub required and that the logic is each vent itself. I’m not sure how that works, only having the one sensor and thus no relative differential, but I’m also not a HVAC guy. Just thought I’d share.
trust me, this logic does not exist in the vent.
the pressure sensor is capable of resolving changes as little as 75Pa, .5InWC = 124Pa, 1.2inWC is about 300Pa.
So in theory the raw sensor should be able to resolve these changes, however I continue to see normal changes within a room, and room to room on the same floor with the vents completely open that are within the range that’s we’re trying to track for excessive back pressure. So I ask again, how can the vent sensor readings be used to prevent back pressure when the readings with a vent being fully open can easily exceed the 125Pa that we’re trying to track?
Do you have any open discussions with them about how this is supposed to work, or are you just not worried about the lack of automated protection? I’d really like to get some vents but I worry I’ll do something stupid and cost more by shortening the life of my system and running inefficiently then the value of my marginally increased comfort.
I haven’t bothered discussing directly with them, as I doubt they are going to divulge how their algorithm works.
They do have an ST community account, they’ve posted here before, all I can presume is they don’t have anything to add to this discussion.
If you’re worried about ganking your system, get their hub, you can always toss it later and join the vents back with ST.
From my POV I haven’t done any automations with them yet as I’m still designing a smart app that will do something beyond simplistically slamming them shut when the room’s temp threshold has been exceeded.
Hi Scott,
Based on my discussion with Keen Home, I’ve created several smartapps which implement some safeguards to avoid closing too many vents and check the temperature inside the vent (based on the vent’s temp sensor) to make sure it’s not too hot or cold.
If you need more explanations and use cases scenarios, please refer to
Specially designed for ecobee thermostats (works with My Ecobee device only), smart vents, any ST connected temp & motion sensors.
The smartapp can not only control your vents’ airflow (based on some calculations to find the optimal setLevel inside a given zone), but also can average out your rooms’ temperature to offset your setpoints at your main thermostat (and much more).
It does basically the same thing as ecobees3’s follow me feature but with any connected ST temp and motion sensors. And, you can specify your own presence timeout in minutes for each room (as opposed to the ecobee3 which will detect your presence or absence only around 2 hours after as a general setting).
You can create multiple schedules and associate them to your ecobee climates/programs for your ultimate comfort during the week.
For any ST connected thermostat(s), smart vents,and any ST connected temp & motion sensors
Same as ecobeeSetZoneWithSchedule, but works with Nest, Lyric, any z-wave or zigbee thermostat(s)
For any ST connected thermostat(s), smart vents,and any ST connected temp & motion sensors.
This smartapp will just open/close your vents inside a given zone (which may include one or multiple rooms) based on some temp (cool and heat) thresholds.
The wiki describes different use case scenarios for each of these smartapps.
You can download them at my store;
http://www.maisonsecomatiq.com/#!store/tc3yr
Regards.
…and use their hub as zigbee repeater, I might add. I ordered their hub today, so I’ll report back the hands on experience when I get it.
I’ve got a pair simple but useful rules for the Vents.
Problem: I have a ceiling-mounted register in a bathroom. Lots of very hot airflow, but if you close the register enough to keep the room at a moderate temperature, none of it ever warms the cold, cold floor.
Solution: one rule uses the temp of the vent itself to trigger - when the vent cools off to 95F between heat cycles, it opens the vent to 100%, to ensure that when heating starts again, it will blast warm air down all the way to the floor, until…
The second rule: if the temp of a ST sensor in the room is below a threshold, the vent remains open 100%, until it hits the the threshold and closes to ~20%, to continue circulating warmed air while the heat is on. If the room is above the threshold, it leaves the vent wide open for 10 minutes anyway to warm the floor before closing to 20%.
This works reasonably well in responding to the bathroom door Open/Closed state, and it does get the floor comfortably warmer.
Yeah thanks Yves, My Ecobee Device still disconnects too much to integrate my thermostat with the vent. I appreciate the suggestion though. Even without the Ecobee/SmartThings cloud problems I’d prefer to stick with the native protection as advertised by the manufacturer, just wish I knew how (or more importantly if) it works. 
No biggie though, I can wait until the technical comparisons between Keen and Ecovent come out to see if they’re accomplishing the claim of automated safety features.
@SBDOBRESCU, sounds great looking forward to your take on it!
I finally have begun working on a Keen vent app.
The app is zone centric, minimally each zone consists of one or more vents, and one temperature sensor other than the sensor in the vent.
Each zone has configuration settings for an offset (± from) your main thermostat set point, this becomes the local set point, minimum vent opening and maximum vent opening are also included.
The control algorithm is currently very simple.
Your main thermostat calls for heat, each zone responds by looking at it’s local set point, if not met, open the vent to the max setting.
Once the local set point is met, the vent closes to the min value for that zone.
As I move though this development process I expect to include the following additional features
-Optional inactivity set backs via triggered switches, contacts and or motion in-activity
-Some sort of safety too many vents closed thingy, be that by pressure, temperature, whatever I can create a deterministic algorithm for.
-zone activity logging to the parent app main page
It’s too soon to release publically, but if a few of you are interested in playing along with me while this app is being developed, please PM me if interested or with questions.
There will likely be a release every day or so while these features, and probably others are implemented.
Sign me up. I have been using rule machine but want to have the room temp control calls for heat or cool
FYI, I’m not intending on allowing the room zones to control the main thermostat set points at this point in time.
PM me if still interested in participating.
Mike
Here is what I have setup so far.
Ecobee3 thermostat and three remote ecobee sensors.
8 Keen vents.
We have a 4 story house and each floor has a temp sensor with the main floor the thermostat.
1 Basement, 2 Main, 3 Bedrooms, 4 Children Bedrooms
I have programed using rule machine two states for the vents a day and night. Day opens vents on floor 1,2 and 4 and the ecobee averages temp across the relevant sensors. Night opens vents on 3 and 4 and uses the ecobee sensors on the relevant floors. These rules run well and day and night temps are managed accordingly.
I have setup an auto vent sequence during the day comparing the temp on the 4th floor and 1&2 and opens and closes vents by an increase or decrease based on a difference in temp between the floor sensors. This is a simple rule in rule machine and holds a less than 1 degree difference between the floors.
The features I am looking to add to the system are; only move the vents when heat, cool or fan is actually on, otherwise its wasting battery in the vents. Second the auto vent sequence is reversed during summer and is dependent on the state of heat vs cool. I can accomplish this at worst case using a temp sensor in a vent and having a virtual switch toggled if the temp is above or below a setpoint not ideal. I would like to be able to just read the thermostat state and apply it to my set of rules. It appears rule machine will not be adding this feature so I can always fallback to my original idea.
Brian, what was your placement strategy of your vents? I have 2 vents/ kids bedrooms and was wondering if I should replace them all or just 1 in each room. Just curious what others did too…(initially Keen website was advocating not changing all of your vents. Well now they updated their site to say “replace them all for ultimate control”) @Mike_Maxwell, @yvesracine, @johnconstantelo, @ashutosh1982
This this would depend on how quickly the room can come up to temp, and how far over temp it currently goes.
If the room is always too hot, and gets there fast, then both vents…
I’ve noticed so far that some of my rooms come up to their set points way quicker than others, these rooms are then candidates for closing down entirely when their set points are reached.
So I’ve replaced every vent in my home with the exception of two that were odd ball sizes, these fortunately also happen to be against two walls that have the highest heat loss, and are the most occupied room in the house, so they would never be shut down anyway.
Good point!!!
Wow, really?..I need to take a new mortgage to do that in my home 
I have 6 vents only in my master bed…and then add 2 or 3 in each bedroom, plus hallway, bathroom, etc…and that’s only on the second floor Was hoping will be cheaper to add vents than adding more zones to my zoning panel 