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  1. #1

    Question Balancing existing duct system with fans

    I had a pro install a new natural gas, forced air Heil 150000 btu in my 1971 Alexandria Virginia colonial basement. He hooked it up to the existing duct system, which was installed on the far left side of the basement. The furnace he replaced was the same size, he said.
    He never balanced the system and now no longer returns my calls. On the left side of the house the force of the air is strong and the house gets warm. On the right side of the house, (the footprint is 36 wide by 30 deep), it stays cold or at least a solid 10 degrees below the other side. On the second floor the left side is warm and the right cold, as below. The pro says balancing the system is not part of the job. Is this standard practice?
    I have tried to balance it myself, but simply closing and opening the registers does no good at all. Two other pros have looked at my ductwork and just scratched their heads and left. One suggested that I install a fan on the round 6inch duct that goes 30 ft. across the basement to feed the dining room above and dual fans on the rectangular trunk lines that go about 15 ft. across the basement before turning up into the walls that feed the rooms above. Does anyone have any experience with installing such fans? How can I find somone who has experience with such a situation?

  2. #2
    Join Date
    Aug 2007
    booster fans are a waste of time effort and money, find a contractor to redo, or add dampers to your ductwork to solve the issue.
    You can't fix stupid

  3. #3
    Join Date
    Aug 2002
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Call around and ask,"can you do a Manual J,S ,and D to size,select equipment, and redesign my ducts??"

    Keep dialing until you get a yes.

    Where are the return ducts and grilles??

    Chances are the ducts that run to the far side of the house are too small where they run thru the basemnet to get to the far side,calculations used in the above manuals will tell for sure.

    It would have been better if the installer addressed the issues before replacing ,but the duct issues sound like thet are pre-existing the work he did.

  4. #4

    Smile Balancing Duct system with Fans

    What do J,S and D stand for? I would like to sound as if I know something of what I am talking about when I cold call a company.
    The top return grill is in the second floor center hall. This line also has an a grill open to the family room on the first floor. Another grill opens onto the living room. These two return lines join into a very big, or at least wide return, maybe 3 or 4 ft. wide, 8 to 10 " high, that finally feed into the furnace.
    I thought this system was unique, but I have found other houses built at the same time in this neighborhood with exactly the same system. The one I spoke with said the AC in the far upstairs bedroom was poor, but the heating is okay. In mine the heat is just a trickle, (it goes through 3 90degree bends after it leaves the trunk line in the basement).

  5. #5
    Join Date
    Jul 2007
    Phoenix, AZ
    Did you have this problem with the old furnace they removed??

  6. #6

    Balancing duct system

    Unfortunately I do not know how the old furnace performed. I bought the house in need of work and immediately had a pro that I had used before in other houses examine the situation. I do not think he even bothered to turn it on to check whether the ducts heated the house. But at that time the system was almost fully visible, because there was no drywall in the basement and much of the first floor. Even then I could tell the ducts in the far side of the house went through a 3 full right angle turns in order to reach the upstairs bedrooms. But the system had existed for 30 years, so it must have been okay for the previous owners, or at least that is what seemed plausible at the time.
    I forgot to add that there are other houses in the neighborhood with exactly the same duct work. I have not yet asked about their experience.
    Last edited by rkthomas13; 11-24-2007 at 04:45 PM. Reason: New information.

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