Page 1 of 2 12 LastLast
Results 1 to 13 of 19
  1. #1
    Join Date
    Apr 2012
    Location
    Princeton NJ
    Posts
    125

    Cold air down large staircases

    Hi, I have 1500 sq ft upstairs serviced by what should be an oversized 3 ton ac. It can't quite keep up when the temp is high 90s inside is over 80.
    There are two wide and open staircase going upstairs. Are they significantly contributing to the issue? How much of the cold air is "lost" to the other floor?

    Thanks. Steve

  2. #2
    Join Date
    Mar 2009
    Location
    Mount Holly, NC
    Posts
    3,548
    the problem is threefold, one, you have cold air falling down the staircases, two, the warm air from down stairs is being pushed above it warming the air upstairs, and three, your attic is pummeling the ceiling with hot air, and radiant surface heating is occurring from the attic high temps as well.

    energy auditing is your friend.
    The TRUE highest cost system is the system not installed properly...
    The three big summer hearththrobs...
    Mel Gibson
    Dwane Johnson
    The A/C repairman

  3. #3
    Join Date
    Apr 2012
    Location
    Princeton NJ
    Posts
    125
    Ok but besides adding more insulation to the attic I wonder if there is anything else (1995 house well constructed)

    And that also means that the 4.1 cooling load for the 1st floor is too high for my new ac to be installed in 2 days! Any way to estimate the cooling contribution? Any other fixes? Some sort of cross floor air circulator?

  4. #4
    Join Date
    Dec 2010
    Location
    The Quad-Cities area (midwest).
    Posts
    2,744
    Quote Originally Posted by central nj View Post
    Hi, I have 1500 sq ft upstairs serviced by what should be an oversized 3 ton ac. It can't quite keep up when the temp is high 90s inside is over 80.
    There are two wide and open staircase going upstairs. Are they significantly contributing to the issue? How much of the cold air is "lost" to the other floor?

    Thanks. Steve
    The way I read your post is that you have a 3 ton A/C just for the (1,500 s.f.) 2nd floor? Do you have a A/C system cooling the lower level?

  5. #5
    Join Date
    Dec 2004
    Location
    Grand Rapids, MI
    Posts
    625
    were are the second floor returns ?
    luck dan

  6. #6
    Join Date
    Dec 2005
    Location
    Cincinnati, Oh
    Posts
    5,348
    Quote Originally Posted by central nj View Post
    Ok but besides adding more insulation to the attic I wonder if there is anything else (1995 house well constructed)
    I just came from a "well constructed" 1999 home. Got up in the attic, There was a 10'x10' space that the insulators didn't blow celulose into, I guess because it was hard to get to. That, and half the attic only had 4" of celulose (which is worth about nothing).

    That, and the massive attic (enough to play football in) only had 5, 6" roof vents, so no attic ventilation. It's been about 85-90* for the last 3 days, and about 130* in the attic.

    Guess what? The second floor doesn't cool correctly.
    Thats todays standard of "well constructed".

    Energy audit.
    "Better tell the sandman to stay away, because we're gonna be workin on this one all night."

    "Dude, you need more than 2 wires to a condenser to run a 2 stage heatpump."

    "Just get it done son."

    Dad adjusted

  7. #7
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    4,508
    1st things I would check are the air filters and the condenser (outside part) to make they are clean. These are the 2 most common causes of poor cooling complaints.

  8. #8
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,778
    Just because a house was recently built doesn't mean it was built well

  9. #9
    Join Date
    Apr 2012
    Location
    Princeton NJ
    Posts
    125
    Ok, thanks for the comments so far. 54regcag--had had the unit recently seviced, but it is 17 years old.

    Jtrammel, good point. Will have someone look into it.

    George2---yes. Two systems. Will be 4 tons downstairs. This great forum convinced me to literally beg the company to downsize from 5 to 4 tons for first floor. I had to sign a waiver. The load was 4.0-4.3.

    Mr. Hvacvegas sir (thanks for help on other posts!!!)--got your point. I will have it looked at, good point.

    Daniel Workbee—there are 5 low down near the floor, 16x10 return grills, one in each room, and one in the hall. 8 supplies in the ceiling (one in each room, bathrooms, 2 in the hall).

    Maybe make the kids close the doors to all rooms? Would that kind of trap the cold air up stairs?

    Regardless, how big of a cooling loss are the double open stairways? Will it mess up the load that was done for my downstairs unit?

    Thanks
    Steve

  10. #10
    Join Date
    Dec 2005
    Location
    Cincinnati, Oh
    Posts
    5,348
    Quote Originally Posted by central nj View Post
    Ok, thanks for the comments so far. 54regcag--had had the unit recently seviced, but it is 17 years old.

    Jtrammel, good point. Will have someone look into it.

    George2---yes. Two systems. Will be 4 tons downstairs. This great forum convinced me to literally beg the company to downsize from 5 to 4 tons for first floor. I had to sign a waiver. The load was 4.0-4.3.

    Mr. Hvacvegas sir (thanks for help on other posts!!!)--got your point. I will have it looked at, good point.

    Daniel Workbee—there are 5 low down near the floor, 16x10 return grills, one in each room, and one in the hall. 8 supplies in the ceiling (one in each room, bathrooms, 2 in the hall).

    Maybe make the kids close the doors to all rooms? Would that kind of trap the cold air up stairs?

    Regardless, how big of a cooling loss are the double open stairways? Will it mess up the load that was done for my downstairs unit?

    Thanks
    Steve
    It's called "stack effect". Look up in wikipedia for more information. Learn alot about it for air sealing your home.

    Your thinking the other way around though. If it's comfortable downstairs, but not upstairs, then keeping it open would help suck the heat downstairs. Heat always moves to cold, more so than "heat rises".

    Unless I'm just tired and thinking backwards.
    "Better tell the sandman to stay away, because we're gonna be workin on this one all night."

    "Dude, you need more than 2 wires to a condenser to run a 2 stage heatpump."

    "Just get it done son."

    Dad adjusted

  11. #11
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    3,327
    besides adding more insulation to the attic I wonder if there is anything else

    lots of anything elses...adding insulation over air leaks is wasting money.
    air sealing goes a long way to allowing insulation to perform.
    air moving through insulation reduces insulation values.

    living space walls that are shared with attic space have lots
    of heat gain from hot attics. insulation alone doesn't do much
    to solve these issues. if you insulate and then air seal the wall
    with foam sheathing boards, then the living space is easier
    to cool. and heat in winter time.

    I'm not hearing good things about nj clean energy free audits.
    it may be a starting point, but hiring an indpendent rater/auditor
    would give you unbiased information that could save you much
    more than minimal savings through utility sponsored audits.

    best of luck.
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  12. #12
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    Quote Originally Posted by jtrammel View Post
    Just because a house was recently built doesn't mean it was built well
    Very sad and very true.

    What hasn't been mentioned, is that much of the air movement down the stairs is partly due to reverse stack effect. Air leaks upstairs and cause warm humid air in the summer to leak in, and conditioned air leak out downstairs. The flow is reversed in winter.

    The layout plays a major role, but I have a very wide open stairwell and there is cool air rolling down the stairs, but overall the upstairs is mostly isolated from the downstairs.

    I would focus on attic insulation and air leaks (can lights, bath fans, ceiling fixtures) and attic venting.

  13. #13
    Join Date
    Jul 2005
    Posts
    5,576
    It's premature to blame the capacity issue on infiltration. Have the unit checked out, then take it from there. There are several different issues that can result in low capacity.

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