Page 1 of 2 12 LastLast
Results 1 to 13 of 24
  1. #1
    Join Date
    May 2010
    Posts
    6

    How to approach hot 2nd floor/ductwork issue?

    1941 Colonial two story home (1600 sq ft.) in Richmond, VA. Ruud Central AC with 1-speed blower.

    During summer, the top floor of the house constantly runs uncomfortably 5-6 degrees warmer than the ground floor.

    Looking at my ductwork, it's pretty clear why: There is a damper which controls the upstairs vs. downstairs air flow, however the damper is located AFTER four small ducts have already branched off to registers on the ground floor. So even when I move the damper to direct air flow 100% upstairs, the A/C is pouring out those four registers to the ground floor. Meanwhile the air flow at the upstairs registers is anemic.

    Would love to get some pro advice on the best way to approach this? Ask a pro to move the damper? Install tiny dampers on the four branches? Put inline duct fans upstairs? Other? Thank you!

  2. #2
    Join Date
    May 2012
    Location
    San Diego, CA
    Posts
    352
    Is the return air register upstairs or downstairs? Where is your thermostat located? Does the four supply registers have adjustable dampers like these (http://www.indoorcomfortsupply.com/c...tion&key=328)?

    If not, you could install adjustable ones. Krueger and Titus have good ones.

    or...

    You could just install ceiling fans that can go both forward and reverse.
    You can call me Sam

    It should be a crime to be a mechanical engineer in San Diego
    Summer Design Temperature: 83 F Dry Bulb ~ 69 F Wet Bulb (California Climate Zone 7)

  3. #3
    Join Date
    May 2010
    Posts
    6
    Thanks for the reply hcong!

    There are multiple return air registers both upstairs and downstairs.

    Thermostat is downstairs.

    The four downstairs registers do have adjustable louvers, however they don't close/seal well and air being forced through them becomes obnoxiously loud. Also if I were to completely seal them, I would worry that the ground floor might actually become too warm.

    The second floor does have ceiling fans with reversible direction. They certainly help.

  4. #4
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    4,456
    Especially in climates where cooling is a major factor, the duct system should be designed to favor the upstairs in the cooling mode.

    I'd like a 1st floor, 2nd floor two zoned system; also with dampers on the branch ducts, where they come off the main or plenum, for adjusting flow to individual rooms.
    Is the ductwork in the basement?

    When all things are done correctly, including proper home (& duct when needed) insulation & controlling air infiltration rates, temp differences are no longer a problem.

    Locate an air balancing expert...
    Last edited by udarrell; 07-01-2012 at 12:26 PM. Reason: where they come off the main or plenum...

  5. #5
    Join Date
    May 2012
    Location
    San Diego, CA
    Posts
    352
    Yeah, sounds like you need dampers on those 4 registers, if you have space you can put the dampers farther away from the registers to reduce noise.

    You could try putting a remote sensor upstairs where it is hotter and hook the RS up to the downstairs thermostat. This will help keep your AC on longer but your downstairs will probably get a lot cooler as a side effect. Also, this might not be a good idea if you are not getting any air upstairs.
    You can call me Sam

    It should be a crime to be a mechanical engineer in San Diego
    Summer Design Temperature: 83 F Dry Bulb ~ 69 F Wet Bulb (California Climate Zone 7)

  6. #6
    Join Date
    Aug 2011
    Location
    Eastern Shore, MD
    Posts
    798
    www.certaincomfort.org

    you can find certified air balancers there who will solve your problems

  7. #7
    Join Date
    Jun 2006
    Location
    Richmond, VA
    Posts
    2,683
    In June, we have eliminated those problems for 3 customers in the richmond area.....

    We split the house into two zones and put a new system upstairs and one downstairs.
    It's not the Brand with the fewest repairs-It's all in the install!!! Attention to detail and using the best materials!

  8. #8
    Join Date
    Aug 2010
    Location
    West Monroe, LA
    Posts
    1,440
    Quote Originally Posted by beshvac View Post
    In June, we have eliminated those problems for 3 customers in the richmond area.....

    We split the house into two zones and put a new system upstairs and one downstairs.
    The Org. Poster should call you. You have solved (3) customers problems
    In his area. My vote call beshvac and get him out to review over your system!
    One system two floors never works right even with zoning which helps. There is nothing like one system per floor to truly get comfort for your home. At the end of the day it will save you the headache of trying multiple things that may or may not work.

    There is no better referral then a company that has done this in your area with satisfied customers. Give beahvac a call!!!

  9. #9
    Join Date
    Aug 2009
    Location
    Beatrice, NE
    Posts
    1,746
    If 4 registers can handle enough air that you don't get much on the 2nd floor you have issues with duct size, and maybe blower size. Sounds to me like you need a whole system review with air balancing.

  10. #10
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    Quote Originally Posted by kls-ccc View Post
    If 4 registers can handle enough air that you don't get much on the 2nd floor you have issues with duct size, and maybe blower size. Sounds to me like you need a whole system review with air balancing.
    +1. The problem is likely further compounded with undersized upstairs main branch and ducts and possibly an oversized system as well. It can be nearly impossible to balance a system if balancing it requires that static pressure start climbing to a point where you're not only short on cooling airflow but velocities have climbed to a point where it's really noisy.

    I have continously found that balance at the damper is almost worthless unless you have very low velocities. All you get is noise and leaky ducts. The only place I adjust dampers at the register is bathrooms where I want less air in summer and more airflow in winter so it's a little warmer in there.

    Get a pro in there is evaluate it and add dampers at the start of every branch if possible, then either manually balance the system, or do a load calculation and duct caluclation and use a flow hood to set the flows per the calculations. The manual method is a bit crude and slow, but does work.

  11. #11
    Join Date
    Dec 2010
    Location
    The Quad-Cities area (midwest).
    Posts
    2,481
    Quote Originally Posted by motoguy128 View Post
    +1. The problem is likely further compounded with undersized upstairs main branch and ducts and possibly an oversized system as well. It can be nearly impossible to balance a system if balancing it requires that static pressure start climbing to a point where you're not only short on cooling airflow but velocities have climbed to a point where it's really noisy.

    I have continously found that balance at the damper is almost worthless unless you have very low velocities. All you get is noise and leaky ducts. The only place I adjust dampers at the register is bathrooms where I want less air in summer and more airflow in winter so it's a little warmer in there.

    Get a pro in there is evaluate it and add dampers at the start of every branch if possible, then either manually balance the system, or do a load calculation and duct caluclation and use a flow hood to set the flows per the calculations. The manual method is a bit crude and slow, but does work.
    I agree with this post. You will probably find that a combination of dampers and balancing along with a A/C mini-split is in order.

    A seperate unit/system in the attic is fine but very expensive.

  12. #12
    Join Date
    Jun 2006
    Location
    Richmond, VA
    Posts
    2,683
    Quote Originally Posted by George2 View Post
    I agree with this post. You will probably find that a combination of dampers and balancing along with a A/C mini-split is in order.

    A seperate unit/system in the attic is fine but very expensive.
    One of the houses we did last month had this little tiny 10x10 chase that ran through a masonry fireplace (it was actually a space designed for this purpose) Worked good for the oil furnace (heating only) when the house was built.....but adding AC to it.....well....let's just say it was never going to work no matter how many dampers you put on the system
    It's not the Brand with the fewest repairs-It's all in the install!!! Attention to detail and using the best materials!

  13. #13
    Join Date
    Dec 2010
    Location
    The Quad-Cities area (midwest).
    Posts
    2,481
    Quote Originally Posted by beshvac View Post
    One of the houses we did last month had this little tiny 10x10 chase that ran through a masonry fireplace (it was actually a space designed for this purpose) Worked good for the oil furnace (heating only) when the house was built.....but adding AC to it.....well....let's just say it was never going to work no matter how many dampers you put on the system
    I agree. Some homes (old or new) just don't have enough supply volume to A/C the second floor.

    Manual volume dampers will help if the ductwork is close to being okay. Of course, automatic zone dampers is better yet when possible.

    A second system is great if money is no object.

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event