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Thread: What Should?

  1. #1
    Join Date
    Jul 2012
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    What Should?

    Hello gentlemen. For starters I am new to this site and love it.

    My question is two parts, but should be simple to answer.

    First…..What should a quote look like?

    Particularly, I plan to have all of my duct work replaced with a correctly engineered duct system. So I want to have a selection of professionals come out and provide me a quote for the work. How will I be able to tell from their submissions which vendor has done all the correct calculations and design work and if his math is correct?

    Second….once a vendor is selected and work is in-process/completed…..How will I be able to tell that the installers work meets the intent of the quote/design?

    I hope this question is not too vague, but it is what I am asking myself at the beginning of this venture.

    Please feel free to ask question or probe concerning the project.

    Thanks in advance for all of your help.


  2. #2
    Join Date
    Jul 2010
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    Duct design is a matter of using the correct size to get the desired air flow into each room while keeping the system total external static pressure at or under .5". Checking after the fact is a simple TESP test on the system and air flow measurement at the registers. TESP measurement take less than 10 minutes on most systems. Air measurement and balance in each room can take several hours.

  3. #3
    Join Date
    Oct 2010
    Anderson, South Carolina, United States
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    The contractor should be able to test the home with sophisticated tools. Go to to find a contractor who can do this. Department of energy has some good resources and your local utility provider (power company) may provide some resources. Some utility companies are offering rebates for qualified systems. Blower door testing and duct testing are the only way to ensure your duct is properly sealed. Ask the contractors quoting how they will Determine the size of system your home needs. Comfort institute members should ask all the right questions, they have invested a lot of time and money on equipment and training to do jobs correctly. The nor dyne IQ drive unit is a really neat piece of equipment, it must be installed and ducted properly, it is branded under the names of maytag and broan

  4. #4
    Join Date
    Jul 2004
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    A. The quote should describe all of the work to be done in detail, including design, installation and verification of operation upon completion. If specific standards to be met are a requirement, then those should be spelled out in the quote, as well as the method of verifying compliance with those standards. The fact that a Manuals J, D, S, T & Z (z if zoned) have been used in the design should be stated. Any omission of such manuals should be cause to disqualify the company from the work.

    B. Verification of installation practices can be done different ways but it all adds up to the same thing. Airflow should first be verified under a specific set of conditions, such as wet or dry coil. Balance of the system would normally be done using a flow hood at each supply outlet and return grille. Proper refrigerant charge (for AC or HP) should be verified using both SC and SH as references and charging with the appropriate method for the equipment installed.

    You didn't state in your post what type of equipment is to be attached to the duct system. If it's a gas furnace, further testing should be accomplished to verify gas pressures, combustion efficiency as well as airflow in both heating and/or cooling if appropriate. If by some chance it's and oil furnace, further tests of oil pump pressure, exhaust smoke and draft should also be included. Full set-up of any thermostats in the project should be accomplished as well and all design, installation, maintenance and service paperwork, including manuals, should be left on scene in good condition. If there are any rebates due, the installing company should supply all necessary supporting documents as required to qualify the equipment for those rebates.
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