Recent experience with electronic duct dampers?

[IVB]

Anyone have any recent experience with electronic duct dampers (HVAC) , good or bad?  I have a forced air furnace, need to balance out temps between 1st floor room. I have manual dampers on a few runs but its a monstrous PITA to go through crawlspace to the damper location, tweak it, wait an hour, etc. Looks like they're $100 or less, I could put them on half the runs and adjust it with a beer in my hand on the couch. 

 

[pete_c]

Here manually for a time changed 2nd floor and 1st floor return flow relating to the forced air cooling or heating against the wishes of a friend who owned an HVAC company.  It was a WAF effort. 
 
I have taken air pressure measurements in commercial applications and never did do that at home.  I do use an IR temperature gun here which I purchased way long time ago.
 
I have been told though that the ducts  / size of plenums / dampers / adjustments are set and typically fixed so as to not starve the flow of air one way or another. 
 
You can adjust with the proper tools but it's a PITA and your mentioning of having to go to the crawlspace damper locations to do this makes it sound to me like you are not a happy camper.
 
Over the last couple of years have seen the sale of Z-Wave managed damper controls and the topic coming up on Homeseer forum.   The same answers of not dicking around with the air flow in a home were provided.

 

[IVB]

Man if there's one thing that doesn't describe my house, its "typical". There are *8* exhaust vents (in a 1700 sqft footprint) and one 2'x3' intake. Not one thing is set. Plus i'm tracing the duct runs as we speak, it is the most bizarre setup. There aren't 8 ports on the furnace, random duct runs are split, others aren't. (our kids bathroom has a giant vent with a 5' run, and it destructively hot while the bedrooms are freezing).
 
The HVAC guy came out, told me exactly what to do (what I outlined above) given the sheer # of runs. Its just that accessing the location is a royal hassle.  He told me that dampers at the grill are stupid as you're cutting off the air at the worst location, which is the end of the run. Esp since I actually have inline dampers. 
 
Reason #366 why a 105 year old house thats had 4 prior owners each of which extended the house is both a blessing and a curse.

 

[pete_c]

Yeah here the inline (in ducts) are all by the furnace / HVAC structure in the basement such that they are easy to get to but never have been touched.  There is one on every duct as they split off from main ducts.  These are typically adjusted right after first turn on and is where if anything flow measurements are made.  I have though never seen this done in a home (it uses a canopy over a duct or a flow tool that is inserted in a small drilled hole right in to the duct).  The initial design though matches the in and out square footage of duct work, diameter of ducts etc...gets way involved...most of the efficiency relating to tin cutting (duct work) which is truly an art.
 
Well too actually the attained knowledge base of an Obi Wan HVAC diagnostician is a leaned art.  He can hear, touch and feel temperatures and just knows what it is that needs to be done.   It sounds to me like your confidence level is high relating to the suggestions.  There are no shortcuts though.  That is just the way it is.
 
What I did here related to only the returns as they are in every room of the house.  I would historically change the flow from the summer time to the winter time and vice versa. (doing it at the returns cuz it was fast and easy).  Always though was reprimanded by my HVAC person NOT to do this while concurrently having to deal with temperature/humidity levels of WAF stuff.
 
Did a visual here just now and see only the supplies have the duct dampers and not the returns here in the house (built around 2002) which is the same in all of the rooms with adjustments for the supply and none for the return ducts.
 
IE: my sister decided to purchase an older home in the 1980's versus a new home.  That said it had been updated with a second floor and the stairs were in the kitchen turning a regular kitchen to an extended hallway.  The WAF drove this effort with the supposition that my brother in law would update it; well he started to and never finished and they ended up purchasing (building a new home).  Here we dumped over 250K revising an older home and gave up (after about 50% of the house being done) and decided it was cheaper to tear the house down and start from scratch.

 

[ano]

Anyone have any recent experience with electronic duct dampers (HVAC) , good or bad?  I have a forced air furnace, need to balance out temps between 1st floor room. I have manual dampers on a few runs but its a monstrous PITA to go through crawlspace to the damper location, tweak it, wait an hour, etc. Looks like they're $100 or less, I could put them on half the runs and adjust it with a beer in my hand on the couch. 

Yes did it in my last house.  I would say in your case it might be helpful, but I can tell you, if you are retrofitting an existing system, its very tricky. 
 
So I don't know where you live, or if AC or heat is the main problem, but there are a few things to think about.  If you are just attempting to damper 1/3 the ducts, your probably O.K. but more than that, it becomes tricky.  What type of blower do you have? Is it variable speed? Variable or two-speed compressor? If not it gets more difficult. 
 
Long story short, when you close off dampers if they are much more than 1/3 of the total, and even that is pushing it, you may have problems.  The design airflow over the coil slows, the burners have less airflow and run hotter, AC can freeze up, etc. and you WILL lose efficiency.   I eventually got it working in my last house, but the blower and compressor have to compensate when ducts are closed.
 
I did mine for zoning, so in theory, you could set the temp of each zone and it would maintain it.  It sounds like you are balancing the airflow with dampers. Mine were open or closed, no in between, so maybe yours are different.  Can't you adjust the room vents? 
 
Before I did the zoning many told me that a properly designed system requires very little closing of ducts.  I didn't believe that so I did the zoning, but after doing I now believe those people were right. Dampers are almost never the right solution, they are just compensating for other problems. 
 
I should add to this that I just replaced the 20 year old HVAC system in my house last week. I found a guy who was very experienced and not only did he replace the unit, blower, etc., but he also said the builder undersized many of the ducts and that cause problems. He replaced many ducts with bigger ones and it works great, without zoning or dampers. 
 
Getting your unit to work correctly is an ART, and honestly, I don't think the majority of the contractors really know what they are doing.  If you have the original builder system, 99.99% chance it wasn't installed correctly. A correctly installed and sized unit is a thing of beauty, but also rare in this day-and-age.

 

[Del91574]

Given the cost and time of install, would it be just as economical to bring in the tin knockers and refeed/trunk the house and properly size the ducts so balancing is the only item that needs to be considered.

 

[IVB]

well, this is just a depressing education. 
 

So I don't know where you live, or if AC or heat is the main problem, but there are a few things to think about.  If you are just attempting to damper 1/3 the ducts, your probably O.K. but more than that, it becomes tricky.  What type of blower do you have? Is it variable speed? Variable or two-speed compressor? If not it gets more difficult. 
 
Long story short, when you close off dampers if they are much more than 1/3 of the total, and even that is pushing it, you may have problems.  The design airflow over the coil slows, the burners have less airflow and run hotter, AC can freeze up, etc. and you WILL lose efficiency.   I eventually got it working in my last house, but the blower and compressor have to compensate when ducts are closed.

 
Variable speed. I have 8 dampers, was only going to focus on 3, but I didn't realize automated ones only had open or close, no partial. The manual ones I have allow for partial. That suggests using an automated solution is immediately off the table, and crawlspace it is.
 

Given the cost and time of install, would it be just as economical to bring in the tin knockers and refeed/trunk the house and properly size the ducts so balancing is the only item that needs to be considered.

 
Well, the HVAC guy who came out looked at the system and suggested that as the first step. There is literally zero chance this was designed correctly, as it wasn't ever "designed" in the first place. I have 3 different sets of foundations under the house based on extensions by 3 different owners (me being one of them although my extension is unheated). Some runs seem to have been just forks off existing runs as it was simple.
 
I was hoping to "fix" this for <$500, your solution sounds way more expensive, but I wonder if doing anything less is just a waste of time and money. Ugh. At least I bought my house in '01, before the explosion in home values, so there's considerable equity in it to offset any investment.  Maybe i'll have an electrician rip out the freaking crawlspace electrical disaster at the same time and just start with as close to a "blank" slate as possible.

 

[IVB]

thx to all for the tips btw, i'm thinking about abandoning this until the macro issues are resolved. 

 

[ano]

thx to all for the tips btw, i'm thinking about abandoning this until the macro issues are resolved. 

If your HVAC is pretty old, it sound like you should replace it and start from scratch. Painful I know, but that's really the only way to go.  Your just wasting your money on dampers. There are proportional one, but most are on or off and that is it. I thought you live in N. CA?  Why do you even need an AC or Heat?  ^_^

 

[IVB]

Well, the unit itself is 2002. The ductwork is far older though, predates us, we bought in '01.
 
Oh, and heat only, it does get as cold as 43 here ;-)  

 

[jdk972003]

Have you thought about using some of the zigbee or zwave smart vents?  There are several users out there claiming its completely balanced their house temperatures.  The ones I saw were using them with Smarthings.  a developer ther has an app that ties them into the thermostats and room temp sensors.
 
http://www.amazon.com/Keen-Home-Smart-Vent-x10/dp/B00YCAWCV4
 
They do require batteries but should balance the airflow appropriately.  The best part, you should be able to adjust them to fine tune the system very easily.
 
Expensive but if you have certain rooms with issues it should help.  Something to consider espeacially as you could try them and return them if they do not work.

 

[ano]

Have you thought about using some of the zigbee or zwave smart vents?  There are several users out there claiming its completely balanced their house temperatures.  The ones I saw were using them with Smarthings.  a developer ther has an app that ties them into the thermostats and room temp sensors.
 
http://www.amazon.com/Keen-Home-Smart-Vent-x10/dp/B00YCAWCV4

These look interesting, but the reviews are mixed. Looks like you can open and close them with a smartphone, but who wants to do that.  They are a work in progress.
 
Here is another idea to consider.  I did this in a former home. Instead of a damper to close off ducts with too much heat, consider booster blowers where the heat is not strong enough.  There are several advantages. The blowers don't completely block the vent when off, but give a big boost when on and they help your airflow. A simple thermostat in the room is all you need because the fan likely has its own temp sensor to turn it on and off. 
 
Open all your vents and see where booster fans can help. Its not a great idea to close vents in general because you are restricting airflow in the furnace, which can decrease efficiency.

 

[jkmonroe]

no easy solution for this, gotta fix it right.
 
balance out your system (might cost $$$) and automated vents don't matter.
 
HVAC can be really simple - volume of air in your home needs to be conditioned.  in order to do so, you need to take that air via the returns, run it through your conditioner (ac or heat), and pipe it back into the rooms via the supply.  it's a continuous cycle that has a LOT of variables.

 

[IVB]

The problem is that I live in Northern California, labor rates *start* at $90/hour and rapidly rise. A simple slam-in-install is cheap, but the measuring & balancing is big $$. Tough to justify it, but easy to justify DIY experiments. I hadn't thought about using a blower to increase, wouldn't that potentially damage the furnace? I admit to not understanding the mechanics of furnaces and whether i'd create a vacuum situation burning out the furnace blower.

 

[drvnbysound]

I've been following along as I had previously thought of adding a vent to my garage and having it controlled via a damper depending on the state of the garage door. I've still not done anything in this area.
 
Having said that, the mention of a blower reminded me that was done at my in-laws house shortly after their home was built ~10 years ago. At that time, 2 of the bedrooms (furthest from the unit) were staying a bit warmer than the rest of the house. The HVAC guy ended up installing a fan (in or in-line with the ducting) on each vent in those rooms that turned on when the HVAC unit turned on. So, basically when the HVAC was running the fans help to get air through the ducting and into those rooms. It's worked well and they have had no issues since the fans were installed.