Recent experience with electronic duct dampers?

IVB said:
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.
No you won't damage your furnace. Your far more likely to cause damage with dampers.  You need a minimum airflow in the furnace NOT to damage it. Booster fans just overcome some of the air resistance introduced by long ductwork.  You would add these to the vents furthest from the furnace.
 
boosters are bandaids to oversized trunk lines....you oversize, you lose the velocity, which chokes the airflow at the furthest points. Depending on the cost of labor in your area, generally it's just as easy to pull a couple of Pittsburghs and then resize from the closest seam.
 
The issue with pulling new lines is that I need someone far smarter than me to design what it should look like. And those who design will insist upon staffing the labor to pull. Even easy things are over $2K, harder things are more. And to get someone to fit in a $2K job would require serious lead time and they'd still "get to it when they can get to it".  Tons of people throwing $10K or more to put in all new systems.
 
It just took a 3.5 month lead time to get someone to come do an annual maintenance checkup on my furnace. I'd rather not wait 2-3 months to address these issues, just to still have to spend thousands.
 
IVB said:
The issue with pulling new lines is that I need someone far smarter than me to design what it should look like. And those who design will insist upon staffing the labor to pull. Even easy things are over $2K, harder things are more. And to get someone to fit in a $2K job would require serious lead time and they'd still "get to it when they can get to it".  Tons of people throwing $10K or more to put in all new systems.
 
It just took a 3.5 month lead time to get someone to come do an annual maintenance checkup on my furnace. I'd rather not wait 2-3 months to address these issues, just to still have to spend thousands.
That what you get when your neighbors are Mark Zuckerberg, Sundar Pichai and Tim Cook. HVAC guys know that and price accordingly.  Don't they have those guys around you that hang out around Home Depot that you can hire for $5/hour, cash or pesos accepted. ^_^
 
ano said:
That what you get when your neighbors are Mark Zuckerberg, Sundar Pichai and Tim Cook. HVAC guys know that and price accordingly.  Don't they have those guys around you that hang out around Home Depot that you can hire for $5/hour, cash or pesos accepted. ^_^
 
The absolute cheapest you can get HD guys is now $19/hour, and those are NOT guys you'd want to hire.
 
If I could get someone to look at the house & design it, everything else would be simple. Alas nobody is willing to do that, as they want that add-on fat profit margin.
 
The furnace itself is approaching 15 years old. If I land my next client in the timing I want at the rate I want, I might just bite the bullet and hire a firm to do the whole darn thing.
 
I've dealt with (still do) vent sizing/flow issues in my house.  I'm on the other coast (central FL) so it's all A/C, pretty much zero heat.  1800 sq ft home with 10 supplies and 1 return which is half blocked.  2 main trunk runs and everything else off the trunks.  Return is under the unit which sits in the garage against an interior wall.  New HVAC installed in 2004 and all supplies in 2010'ish (all attic flex duct) a cost of $300/run, which is a typical price out here for flex.  It was sized by a guy at the company who did the work but I know it wasn't done as good as it should have been done.  
 
But, the re-sizing (everything got bigger) helped greatly with keeping cooling more even room to room, but there are still issues with the farthest rooms, and I also have a tun of supply noise. A big part of my issue is lack of more returns, which is critical to a proper design.  I'll actually be doing it all over again in next few years, doing a properly vent design with returns in every room.
 
Out here, I can pay $250-300 and have an independent person do all the load calcs and design.  This is someone who specializes in doing just this stuff, not a random dude at an HVAC company who can spin a manual J wheel and doesn't really care. The catch is getting an HVAC company to use that design and not only do it based on what their inside guy tells them.
 
HDClown said:
But, the re-sizing (everything got bigger) helped greatly with keeping cooling more even room to room, but there are still issues with the farthest rooms, and I also have a tun of supply noise. A big part of my issue is lack of more returns, which is critical to a proper design.  I'll actually be doing it all over again in next few years, doing a properly vent design with returns in every room.
You have hit the nail-on-the-head.  I'm in AZ, another 95% AC state and I have no air returns except the one from the air filter.  This is the major cause of the problems.  Adding returns is great if you can. but its not always that easy.
 
Certainly somewhere in the past, the lobbyists for the construction industry convinced everyone that producing homes with inadequate HVAC systems was perfectly fine, and the homeowner can pay someone $1000's more if they actually want to things to work.  
 
This has been the trend on everything from plumbing to insulating to drywall. Homeowners can just fix it later. A very few builders go over and above the standards to make things right from the beginning, but those builders are far and few between.
 
HDClown said:
Out here, I can pay $250-300 and have an independent person do all the load calcs and design.  This is someone who specializes in doing just this stuff, not a random dude at an HVAC company who can spin a manual J wheel and doesn't really care. The catch is getting an HVAC company to use that design and not only do it based on what their inside guy tells them.
Here is the problem and you really can't blame the HVAC people. Most are pretty competent and know full well of the problems, but they are in a bind. If you have them over to give you a quote for say a new HVAC unit, they easily could price-in the extra effort to make your work well, increasing your duct sizes to where they should be and adding some returns, but the price of the quote would increase. Then along comes HVAC company 2 who says you don't need any of that and their quote is $3000 less.  Which is the homeowner going to pick? Most times its the cheaper one.
 
Well too here in the Midwest the duct work is all relating to the art of tin cutting.   A redo or add will be difficult and expensive.  Helping a friend a couple of years ago accidently reached up in to a duct; blindly and cut my hand on a sharp edge of a supply duct.  The cut was so clean I didn't realize that I was bleeding until my head, ladder and carpeting was full of blood.  Well and it was new carpeting.
 
The only new stuff here I have seen relates to the lower energy cost stuff.  That said and personally the air isn't as cold as it used to be.  That is me though.
 
In the old house the zoned HVAC inside furnaces were in great shape before selling the house.  I did replace the outside units. Two of everything there and no zoned damper stuff.  It was done up in a day.
 
Lines were drained then cut and the new outside AC compressors were installed in some 30 minutes or so.  Then new old new juice was added / pressures were checked and everything was tested and completed by 5PM that day.  No tin cutting that day.  The upstairs unit return was in the hallway (didn't like that) and it had that octopus supply duct stuff in the attic.
 
In FL (gulf side on the water) on a new home build the main HVAC (and there is a heat pump there as well) main handler sits up 20 plus feet in the garage.   I was puzzled that the GC didn't use dryvit for the outside walls as I liked it using it for a building in the MW.  It is sort of fragile stuff stuff though.
 
It is difficult to service (just changing a filter is really no fun at all). 
 
The main return (huge similar to what Ano describes in AZ) is in the main garage entrance hallway while the supplies are all in the attic octopus looking.  Drain pan once got clogged and it rained in the garage for about a few days.
 
Updating the supply and returns would be much more reasonably priced in FL than a bunch of tin cutting in the MW.
 
pete_c said:
Well too here in the Midwest the duct work is all relating to the art of tin cutting.   A redo or add will be difficult and expensive.  Helping a friend a couple of years ago accidently reached up in to a duct; blindly and cut my hand on a sharp edge of a supply duct.  The cut was so clean I didn't realize that I was bleeding until my head, ladder and carpeting was full of blood.  Well and it was new carpeting.
I'm surprised they still use those, because they aren't insulated, are they?  Also they take more labor, and if there is anything the world has transitioned to its less labor. The mylar ducts they use around here seem to work pretty good and after 20 years, seem to still be in good shape. Just mylar, some insulation, and giant springs.
 
Yeah this happened in a friends dental office and the duct work in the office is very old and above a drop ceiling and not insulated.  I was just having a look see.  That said she had just remodeled the office (new carpeting) and is very cold in the winter up there.  We had a commercial building years ago with all of the stuff on the roof including the ducts which were insulated.   Easy to service but not really efficient.
 
Yeah here in the MW they still use metal ducts and do a bunch of tin cutting. None of the ducts are insulated that I have seen in new residential construction as of about 2-3 years ago.
 
Pete, a lot of ducts have insulation on the inside. Counter intuitive, but it's common. Cheaper guys just put the tin in and don't wrap with blanket or put pooky on the seams.
 
Flex duct and the wrap tend to vary on the quality. Around here, they plastic is usually pretty brittle after 15 years....and they provide great nests and homes for rodents.
 
Thank-you Del.
 
Yeah never seen insulation inside of a duct before.  I have seen tin tacked inside of a space 16" between studs used for returns.  In the old house the flex ducting in the attic was insulated such that it looked twice as round.
 
ano said:
You have hit the nail-on-the-head.  I'm in AZ, another 95% AC state and I have no air returns except the one from the air filter.  This is the major cause of the problems.  Adding returns is great if you can. but its not always that easy.
 
Certainly somewhere in the past, the lobbyists for the construction industry convinced everyone that producing homes with inadequate HVAC systems was perfectly fine, and the homeowner can pay someone $1000's more if they actually want to things to work.  
 
This has been the trend on everything from plumbing to insulating to drywall. Homeowners can just fix it later. A very few builders go over and above the standards to make things right from the beginning, but those builders are far and few between.
 
I think this is the big issue around here. Land & housing is so expensive nobody pays much for minor areas. The standard lot on my street is .09 acres (40'x100'), the 2000 square foot house 6 doors down which is nice but not super nice just went for $2M, or $1K/sqft.  The old dilapidated 1300sqft house 3 doors down went for $900K, was fully torn down, new owners spent far over $1M (won't say how much more), and have a gorgeous place.
 
People spend $$ in $5K increments around here, and $5K is for enhancements not replacement. The worlds crappiest HVAC would not impact house price even .00001%, people are used to just ripping out the old 100% and putting in the new.
 
IVB said:
The standard lot on my street is .09 acres (40'x100'), the 2000 square foot house 6 doors down which is nice but not super nice just went for $2M, or $1K/sqft.  The old dilapidated 1300sqft house 3 doors down went for $900K, was fully torn down, new owners spent far over $1M (won't say how much more), and have a gorgeous place.
 
Pretty amazing... my wife and I were just looking at (2) adjacent lots that would total just over 1 acre and back up to a man made lake. Currently listed for 79k :)
 
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