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  1. #1
    Join Date
    May 2007
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    Temperature difference between floors

    Hi. I need some advice. My husband and I moved into a new construction house in January 2007. We have a 1600 sq ft colonial on a slab. Our hvac is a single stage Goodman. When we would run the heat in the winter I kept it at 73. The downstairs was comfortable but the upstairs was bone chilling cold. From what I understand on a slab it is a bit colder than if having a basement. I had the company out that installed the system and they recommended better weather stripping for the windows..which we had someone out to do. We even put the plastic on the windows which helped a tiny bit..but we still had to dress very warmly for bed. Now that warm weather has arrived we have had to turn the air on. Now the problem is just the opposite. It is cool downstairs but very warm upstairs. I do expect a temperature difference but it seems very extreme. I have the thermostat set at 70 just so the upstairs is comfortable enough to sleep in and it is still very warm. The minute you walk up the steps you get blasted with warm air. Am I doing something wrong or should I gave the company back out to take another look. I know there should be a temperature difference but it seems so extreme. Any advice or ideas?

  2. #2
    Join Date
    Jul 2005
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    sounds like not enough air going up stairs to me
    location of airhandler and trunk line feeding upstairs and down stairs nothing pinched or broken loose
    location of t-stat
    poor design of duct work, could be a host of problems but i would start at the basics and keep digging till i find out why????

    you stated this is a new house i would make the installing contractor come back till all is fixed

    a properly design systems should hold a constant temp, up and downstairs with a proper design
    once you think you've seen it all
    I would rather work for free than be look upon as a thief!!!!!

  3. #3
    Join Date
    Mar 2006
    The South
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    Sorry for your problem. Unfortunately, your situation is very typical of two story homes operating off one system and without zoning controls. This usually can be blamed on the building and HVAC contractor who want to put in new equipment/ductwork as inexpensively as possible. Most likely your ductwork both supply and return for 2nd floor is undersized. I would determine first from an HVAC pro experienced in ductwork that you don't have any collapsed ductwork serving the second floor. I would also evaluate the size and CFMs of both supply and return for the rooms on the second floor. I would evaluate insulation properties for the second floor. Here are your choices and none are too palatable. nothing and live with problem
    2.make changes to enlarge ductwork to the second floor.
    3.look at zoning the first and second floor off one system-still involves ductwork changes,
    4.put in separate HVAC system with new ductwork for the second floor (overall probably will be the best choice but also the most expensive)
    5.move (not trying to be funny)

    Keep in mind, new HVAC equipment will not overcome bad ductwork design.


  4. #4
    Join Date
    Oct 2005
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    You should have it balanced so you are absolutely certain each room is getting the required CFM you may be sending more down stairs then you are up and one room may get most while another get less. They can also tell you if the system is running at manufactures recommendations.

  5. #5
    Join Date
    Feb 2003
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    3F should be the difference between rooms just after the blower shuts down.
    else, the system is not right.

    run the load calc here so U will know where the issues are --
    read lots herein --
    I have addressed this issue several times, as have others
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  6. #6
    Join Date
    Mar 2002
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    Here is how I explain to my customers:

    Your house is the same square footage upstairs as down, and common sense tells you that you need the sam ammount of airflow up and down.


    In the winter you need 70% of your heat downstairs because heat rises, but in the summer it's just the opposite - 65% cooling upstairs, because cool air falls. Look at it this way, in the summer, the upstairs actually helps cool the downstairs, and in the winter the downstairs actually helps heat the upstairs.

    If you have a 2 story house with one system and you have to be comfortable you have to be able to regulate the airflow between summer and winter. If you have 1 common trunk between floors and have first floor vents in the ceiling and second floor vents in the floor you will NEVER be able to ballance properly unless you block off the second floor floor vents and install a new duct system in the attic.

    If you do this, or if you are lucky enough to have second floor vents already in the ceiling, you can install manual dampers to ballance up vs down airflow or install a automated zoning system with seperate thermostats.

    Hope this helps explain what you are up against.

  7. #7
    Join Date
    Dec 2002
    Tampa, Florida
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    I just don't get it why....

    For the life of me, I don't understand why developers' and contractors' still refuse to offer the home owner a choice of single or dual systems. It is very difficult to condition a 2-story home on one system, even with elaborate zoning systems and such. 2 systems you can control each level independently of each other. Not to mention, what if one system goes down! At least you can live in the other part of your home without too much inconvenience and suffering. I have only been in a few homes where the contractor actually got it right. More often then not, systems that were based on manual D's & J's , seem to be sized for the bare minimum. Engineer's will swear up and down it should work, but instead, end up scratching their head in disbelief. Usually end up blaming some poor installer for the system's inadequacy and failure to cool/heat properly. 2 story houses should have 2 systems IMHO.

  8. #8
    Join Date
    Nov 2006
    Post Likes
    Heat rises. If the upstairs is cold in the wintertime, you have a major problem. First make sure they insulated the attic. If that is OK you have an HVAC design problem. Do you have a stairs door that you keep closed? This will seal the upstairs from the downstairs.
    I agree with several above posters, it is extremely difficult to properly balance the HVAC on a two story house with a single unit. I have never one time installed a single system on a two story, and I don't intend to start. It makes the HVAC guy look like a dork when it doesn't work, and I don't need that.

  9. #9
    Join Date
    Aug 2002
    Office and warehouse in both Crystal River & New Port Richey ,FL
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    Full second story or just a bonus room???

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