HVAC Zones via Duct-Dampers instead of Smart-Vents?

Continuing the discussion from Smart air vents:

Also continuing the discussion from Smart HVAC Dampers?:

Sorry if this has already been discussed elsewhere, but…
This combination of ideas is very interesting to me. If we own the house, would it make more sense to install dampers directly into the air ducts, close to the source of the air-flow than to replace our floor vents in the rooms?

If we put a ‘dumb’ (though electrically controlled) damper in there PLUS a ‘smart’ relay switch, we could have a true zoned system…no?

I guess it seems this would be a bit more expensive than just getting the SmartVents. However, would the efficiency difference be enough to make it worth doing it this way instead?

Also, if we were to do this with either one, is the setup of a SmartApp to manage it all like a zoned system totally ready to fly, or is that part still…um…up in the air?

1 Like

Yeah - that’s what I did

1 Like

If you don’t mind sharing…
What specific physical devices did you use?
Which SmartApp are you using, or is yours controlled by the thermostat?
How many ‘zones’ do you have now?
How long have you had it all set up, and how is it working out so far?

This is exactly how I found ST in the first place. It was my plan to do this. I never actually did it though, but now it’s beck on the list.


Good to hear.
It’s not exactly on the top of my budgeting priority list quite yet, but it could get there quickly if we really figure this thing out.

The price of motorized dampers is high enough, and I’m trying to find ways to chop down the overall cost for a project like this.

Did you use a separate z-wave/zigbee relay for each damper, or something that could handle multiples?

I’m now wondering if it might be possible to make something with Arduino that would only need a single z-wave/zigbee relay.


If placing one in ALL of your ducts I’d really be concerned with a system failure causing far too much back pressure and killing your HVAC system, with the Keen/EcoVent at least they have some additional failsafes.

Just something to keep in mind.

1 Like

Ya, I appreciate that and agree with your point.
It has been brought up for discussion elsewhere, and after careful consideration, I have come to the conclusion that it’s not a real problem (as long as the house is never in a situation in which power goes out only for the ‘smart system’, but not for the HVAC system itself)…

In my case, I have already considered this issue, and will make sure to have a safeguard in place within the SmartApp I end up using (or some other way) that will never allow more than X-number (whatever that is after more research) of ducts to be closed off at any time.

Closing off one or even a few vents can’t be horrible since that’s what we all do all the time anyway from time to time. i.e. They put adjustable vents in there so we can adjust them, and I wouldn’t be doing anything any more than what we all normally do manually. It will just be automated.

Not only that, with the way most of us do it now, it’s actually possible to close off too many vents and not even realize it, because we can’t possibly keep track of every single vent (which, for me means tracking between 5 and 10 vents each on at least five levels) all over the entire house.

This suggests that, with ‘smartness’ added to the mix - whether it’s with Keen SmartVents (which are the brand I’d be getting at this point if I were to go that route) or automated duct dampers like I’m considering here in this thread - we will be much better off than without, regardless which specific solution we end up with.

EDIT: I probably should have prefaced the above with, “The way I see it…”.
i.e. I’m certainly open to hearing other logic on this whole thing…that’s why I’m here :slight_smile: So, if you have other thoughts that may be important for me to consider, please share.

If you don't mind sharing....
What specific physical devices did you use? 

and then I hook them up to a z-wave contact switch:

Which SmartApp are you using, or is yours controlled by the thermostat? 

I just wrote a simple app that said if the temperature in the zone 2 was more than 3 degrees off from the themostat (in zone 1), close the damper on zone 1

How many 'zones' do you have now? 

Just 2

How long have you had it all set up, and how is it working out so far?

I originally set this up on Vera in 2011 or so, but then moved it over to SmartThings in 2013 :slight_smile:


Awesome! Thanks a lot for all of the details. This goes a long way toward figuring things out. I mean, even if I don’t end up getting exactly the same pieces of equipment, it’s always good to see what others have already done.

Since you’ve had it going for so long now, I assume it’s a proven concept, eh?

I just reread this, and may understand it differently now…or just didn’t get your full point originally…
So, do you mean if the SmartThings system fails? i.e. if it somehow fails to open them back up and it’s going along with a bunch of them closed because it closes them, and then somehow messes up physically and it ‘thinks’ they are open when they are actually closed?

Hmmmm…I guess I’m not exactly sure what to do in that case.

I suppose I could add some sort of sensor inside the duct to act as a monitor and to look at the opening to know whether it is open or closed.

I could also use a tilt sensor if I put the damper in a certain orientation.

Even some kind of air pressure sensor might help…i.e. if it thinks it’s open, there should be X-air-pressure in the duct. vice-versa if it thinks it’s closed.

Hmmmm…geez…any other ideas, anybody?

Wow…even more money lol

I guess this is why people get a truely zoned system from the get-go.
Trust me though, if I had been offered that choice over a decade ago when we bought the place, I would have. Unfortunately, it was already done by the time we came along.

So, are we talking either/or, or both of these things?
It seems like I’d probably only need the sail switch, right? (well…I mean…if I already had the motorized dampers). I guess if I don’t have the dampers yet, I might as well just get the CPRD, right?

Thanks. I will check out the URL as well.

So, with the bypass damper, I was thinking that each line of ducting that I have a motorized damper in would need this (i.e. use the bypass damper instead of a normal one), but are you saying that there would only need to be one for the entire system (taking your warnings into account, and just asking based on the idea you’re thinking of in your head)?

Hmmmm(crunch, crunch, crunch…)…So, do you mean that you will have the bypass damper set to normally closed, and then it will open if it senses x-pressure build up, or something like that?

Bypass adjustment is based on the pressure in your system. The gravity controls its damper. Been following your posts, and I really think you should go with a Honeywell zoning panel. And installed by its manuals. You are risking a lot of money if you burn your heat pump. I have had one professionally installed in the spring, icorporated into my existing HVAC, and it works very well. And you don’t need extra sensors or to monitor the pressure. You are adjusting everything through your thermostats.



Thank you for your input.

Along with making sure to build something that’s safe (for me and the HVAC system itself), I am also trying to come up with something that could be implemented for relatively low cost.

I totally understand that, in some cases, since it can’t be done safely, it shouldn’t be done. That said, I also know that there are often multiple ways of doing things that could, if done properly (whatever’properly’ is in the given context), be safe and effective at various investment levels.

Would you have the same concerns in the context of those who are currently buying and installing things like the Keen Home SmartVents? (only asking so that I can gauge your level of concern here)


Is the panel really necessary? Couldn’t we build a SmartApp to do (generally, relatively speaking) the same thing it does?

What about the ‘Retrofit Damper’ I see on that page?
Is that a device that turns a traditional damper into a bypass damper?

1 Like

I am actually looking into adding a few Keen vents myself. First, the panel. It’s not all that expensive and is built for the purpose of zoning a system. It knows when to kick in the furnace or the heat pump or the AC and when to direct more flow to the zone you need. Sure an app can be built to replicate the logic that the panel has, but the panel is fine tuned by HVAC professionals, which may be hard to find amongst ST memebers. They have both the retro dampers ( which would be your existing dumb dampers and the bypass, which would be on a duct addition that you would need to install on your system see picture below.

The dampers are wired into the zoning panel, while your bypass (or at least the one I have) is non electronic but rather opens/closes based on the pressure build up. I’ve done a lot of research and the opinions are split. Some HVAC specialists are saying that adding a bypass to your system is inefficient and not needed, while others say that you must have it.

Back to the vents, adding the zoning was great for increasing comfort between upper and lower level, however, now with more air being pushed upstairs or downstairs, some rooms on the same level are colder/hoter than others. So, like you, I am looking for a way to conteol the additional dampers on the second level main duct. Keen seems a better fit than adding more zones, which would require more thermostats. For a while I was thinking too, to add dampers like @Kristopher did, but I have concerns about controlling the pressure properly.

Bypass duct (the first duct you see coming out of the system and back to the system is the bypass that was added to alleviate the pressure)

1 Like

Thanks, guys.
I can see now that, if I’m going to do something like this properly, it is going to take way more time and effort and R&D and expense than what will be realistically possible for me in the short-term. So, I will most likely put this project on-hold for a while and focus on some of the simpler projects that I already have in the works (not only because of timing, but also allowing myself more time to get up to speed on coding and other things first before I really try to tackle this kind of thing).

Once I’m ready to pick this back up again, I will do so here in this thread.

Thanks a lot for all of the great input. I would much rather hear things that are hard to take BEFORE jumping into it than after when I’m trying to figure out what I did to #%&@ up my HVAC system lol

1 Like

So I have a question. I am currently going through a HVAC overhaul and am installing a new Heater and AC unit. While they are doing all of the work I am considering zoning my system into 3 different zones and controlling them all with Ecobee 3’s now that they are $150 apiece. My question is I have 2 guest rooms that I already upgraded with lights and fans and all the door and window sensors to make them smart, and I have tablets that run Smartthings in each room. Is it possible to use the Keen Vents to virtually zone each room by itself so that the Tablet can act as the virtual thermostat so my guests can control what temperature they want the room to be?

Basically will the Keen vents integrate with an Ecobee 3 which will then go through a zone controller that will in turn control the AC and Heater? Do the Keen Vents then act as a damper that will be virtually controlled by each room’s tablet and temperature sensor?

Looking for ideas if anyone has any.


Dual zone panel here, with 100% Keen vents on second floor (one zone) and Honeywell zwave tstats. Vents act as dampers. Be sure to add a bypass to your system to avoid overpressurizing your system.

pS… I really don’t see the need to get ecobee. You are better off getting some good temperature sensors in each room. I am using Netatmo