GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Air return issue: What is best approach to diagnose why I am not getting good return flow?

BlueMTN | Posted in Mechanicals on

House is about 3200 SQ ft. two story with a single air handler in the basement..
– (original contractor no longer living to question)
– air temp balance is hard to maintain both in summer and winter.
– Had two local companies visit wanting to add a second unit vs diagnosing existing return air paths.

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. GBA Editor
    Martin Holladay | | #1

    Blue Mountain,
    It can be tricky to make sure that a single-zone forced air system serving a two-story house provides balanced comfort in summer as well as winter, especially if the house has air leaks or is poorly insulated. Your contractor's suggestion -- installing two furnaces or air handlers -- isn't crazy. This approach usually results in better comfort, as long as the units aren't oversized.

    One possible (cheaper) solution is to install a centrally located ductless minisplit to serve the cooling needs of the second floor.

    For further discussion of this issue, see this article (and the comments posted on the same page): Keeping Cool in a Two-Story House.

  2. GBA Editor
    Martin Holladay | | #2

    Blue Mountain,
    To assess the performance of your return air system, you need to double-check the design of your existing duct system and then you need to measure air flows through the system's ducts, registers, or grilles.

    For information on how to double-check the design of your existing duct system, see this article: All About Furnaces and Duct Systems.

    For information on measuring air flow through ducts, registers, and grilles, see this article: Is Your Ventilation System Working? (Although the article discusses ventilation systems, not forced-air heating and cooling systems, the air flow measurement techniques discussed in the article can be used to measure air flows through the components of a forced-air heating and cooling system.)

  3. Jon_R | | #3

    Have you tried simply adjusting the registers in areas that are too hot/cold? I would expect that you would need to do it every spring and fall. Other lower cost possibilities are booster fans and/or zoning.

    It's likely that your existing system is over-sized. Be careful about making this worse by adding another one.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |