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Unbalanced Upper and Lower Floor Heat in Duplex

FrankTT Member Posts: 2
edited January 2018 in THE MAIN WALL
I own a renovated duplex (top two floors) in a late 1800s row-house. It was updated with a forced air HVAC system (around 15 years ago) which sits on the roof of the building. In order to get the lower floor to a comfortable temperature, nearly the entire upper floor becomes a sauna. This is especially noticeable when the heat in the apartment below is turned way down/off. The downstairs floor has fairly high ceilings (10-11 feet) and an open staircase leading to the upper floor. I am looking for input on a longer term and near term solution.

Longer term, I am thinking about having the system zoned with motorized zone dampers, and a bypass damper. Since there is sheetrock around the branch ducts, I am imagining this to be a much bigger project than if they were exposed.

Near term, I am wondering if there is an interim, lower cost solution I can pursue that can make the place more livable with more balanced temperatures. I have tenants living in the apartment so the longer term solution isn't feasible right now.

Thanks for any suggestions.


  • Jamie Hall
    Jamie Hall Member Posts: 23,428
    Not too surprising...

    First question: where are the returns? It would be helpful from the heating standpoint if they were downstairs.

    Second question: are there dampers on the air outlets? Can they be fitted? If so, you could try using them to reduce airflow on the upper floor. The drawback to that is they can be noisy when partly closed.

    Another option: ceiling fans. Particularly at the top of that open staircase. They aren't the greatest solution -- they don't do as much as people hope they will -- but they do help some.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EBEBRATT-Ed Member Posts: 15,613
    Depends how tolerant you are of a poor heating system. Warm air, especially overhead warm air heat was a very poor choice when they did the renovation. Are your warm air supplies in the ceiling, baseboard or in the floor? I am guessing the ceiling which is the worst place. Zone dampers may help but you have to watch the air that is moving is enough to prevent overheating the furnace or tripping high limit. A separate furnace for each level (if you stay with warm air) would be much better.

    If you can get the supplies and returns down to baseboard level you have a chance at making it work. The ducts have to be of ample size and the furnace should be sized exactly for the load. Oversizing the furnace will kill the room temperature when it cycles.

    In the interim a few pieces of electric baseboard will help a lot. They can be wired with contactors so the furnace and the electric heat all cycle on the same thermostat. The open stairway doesn't help matters. Cold air drops down from above and hot air rises up the stairwell , and yes both can occur at the same time
  • FrankTT
    FrankTT Member Posts: 2
    Thanks for the input. As I have not yet lived in this apartment, I need to go over there, in order to answer some of these questions.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,578
    Maybe mini split heat pumps for the lower area?—NBC