Exhaust Fan?
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Thread: Exhaust Fan?

  1. #1
    Join Date
    Jan 2008
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    120

    Exhaust Fan?

    Ok got a question or two, maybe more.

    Installed:
    Carrier 4 ton HP 25HNA948
    Carrier 4 ton coil CNPVP4821ATA
    Carrier 80K BTU 58UVB080
    TStat M-SYSTXCCUID01

    We have a very old two story house. Went through the Manual Tests and this is the correct system that was installed.

    We kicked the air on this past weekend and the lower story was cooled very nicely, but the upstairs was still much warmer. (we usually put an extra window AC unit in)

    No there are not any returns upstairs, I do realize this is the problem.

    Now my question: If I would put in a whole house fan towards the "back" part of the house UPstairs would this help "suck" or "pull" the cooler air upstairs? (and leaving all windows shut)

    We are in Ne and the humidity later on in the summer gets pretty miserable.

    Thanks,

    MP

  2. #2
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    It sounds like you have ductwork problems and either need a zone system, manual dampers or new duct alterations to the second floor. If your already short return air then how is the rest of the duct sized? I do not think that a fan would do you much good. It would need to be huge to pull much air and that would make things worse. Look into duct changes. Its probably expensive but comfort is the main issue.
    Its a good Life!

  3. #3
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    Quote Originally Posted by m kilgore View Post
    It sounds like you have ductwork problems and either need a zone system, manual dampers or new duct alterations to the second floor. If your already short return air then how is the rest of the duct sized? I do not think that a fan would do you much good. It would need to be huge to pull much air and that would make things worse. Look into duct changes. Its probably expensive but comfort is the main issue.
    Crap, I knew thats what the answer was going to be but wanted to hear soemone say "you bet" "great idea".

    I'll probably throw the window AC in again.

    Thanks

  4. #4
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    Jun 2007
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    The Twilight Zone
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    Quote Originally Posted by Pegsmi98 View Post
    Installed:
    Carrier 4 ton HP 25HNA948
    Carrier 4 ton coil CNPVP4821ATA
    Carrier 80K BTU 58UVB080
    TStat M-SYSTXCCUID01
    That combo is only 15 SEER (11.5 EER) from an "Infinity 19". ARI# 1190673.

    That's a pretty fancy and expensive 15 SEER system. Also only gets 44,500 btu cooling (almost 10% short of a full 4 tons).

    Not sure why you would put in a top of the line Carrier and keep the poor ductwork that requires a window shaker in the bedroom.

    Good luck.

  5. #5
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    Pretty sure you need to open some windows to make a whole house fan work properly.

  6. #6
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    Jan 2004
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    Lancaster PA
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    As others have said, the whole house fan isn't a good idea, and would cause more troubles.

    It could be as simple as balancing your supplies. To make it better. (not right) Your static pressure should also be checked.
    There is a way that you can do it. I'll let one of the other Carrier owners tell you how.
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  7. #7
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    Sep 2001
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    kalamazoo,mich
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    Quote Originally Posted by Pegsmi98 View Post
    Crap, I knew thats what the answer was going to be but wanted to hear soemone say "you bet" "great idea".

    I'll probably throw the window AC in again.

    Thanks


    "You bet", "Great Idea". What was the question again
    Have you hugged the Earth today?
    Donny Baker rules

  8. #8
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    Jul 2000
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    Quote Originally Posted by Pegsmi98 View Post

    We have a very old two story house.
    This might be the perfect time to look at how well the 2nd floor attic is insulated. Much of the discomfort from heat on the upper floors can be directly related to lack of insulation in the attic. Is the ductwork for the upstairs located in the attic? Make sure this is insulated to the same value of the attic if so.

    Quote Originally Posted by Pegsmi98 View Post
    We kicked the air on this past weekend and the lower story was cooled very nicely, but the upstairs was still much warmer. (we usually put an extra window AC unit in)

    No there are not any returns upstairs, I do realize this is the problem.
    Do you have a masonry chimney that still runs from the basement at least to the attic? Is it being used for anything? If not these make perfect chase ways for getting return air down from 2nd stories. A sealed liner needs to be dropped down them or they're taken out completely if possible and the entire space used for return ductwork.

    Quote Originally Posted by Pegsmi98 View Post
    Now my question: If I would put in a whole house fan towards the "back" part of the house UPstairs would this help "suck" or "pull" the cooler air upstairs? (and leaving all windows shut)

    We are in Ne and the humidity later on in the summer gets pretty miserable.

    Thanks,

    MP
    A fan of any kind pulling air out of the house is going to pull outside air in through any open window, crack or chimney that it can. This humidity is going to put a tremendous load on any air conditioning equipment you have running. You will basically be trading the warm dry air upstairs with hot humid air throughout the house.

    You can try a lot of "fixes" to make things better, but bottom line your best spent money for the comfort gained will be to have a professional that knows how to retrofit older 2 story homes come over and give you a bid on getting things setup right. Ask them to suggest what to do in stages if money is an issue. Don't forget to include upgrading insulation, but make sure that isn't done before you have any HVAC work done in the attic that may be suggested.
    Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.

  9. #9
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    Jan 2008
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    Quote Originally Posted by firecontrol View Post
    This might be the perfect time to look at how well the 2nd floor attic is insulated. Much of the discomfort from heat on the upper floors can be directly related to lack of insulation in the attic. Is the ductwork for the upstairs located in the attic? Make sure this is insulated to the same value of the attic if so.

    We have R30 i believe in the attic, 15 inches of blown in anyway.


    Do you have a masonry chimney that still runs from the basement at least to the attic? Is it being used for anything? If not these make perfect chase ways for getting return air down from 2nd stories. A sealed liner needs to be dropped down them or they're taken out completely if possible and the entire space used for return ductwork.

    We do have an old brick chimney through the middle of the house, I am not sure if there is room for adding a return through it but have considered it.

    A fan of any kind pulling air out of the house is going to pull outside air in through any open window, crack or chimney that it can. This humidity is going to put a tremendous load on any air conditioning equipment you have running. You will basically be trading the warm dry air upstairs with hot humid air throughout the house.

    My "thinking", of which I don't even pretend to know this HVAC stuff and hired and installed a great system of which we are happy with. My thinking was that an exhaust fan might have created a vacuum and put enough pull on the air available down stairs, I was envisioning a "forced return".



    You can try a lot of "fixes" to make things better, but bottom line your best spent money for the comfort gained will be to have a professional that knows how to retrofit older 2 story homes come over and give you a bid on getting things setup right. Ask them to suggest what to do in stages if money is an issue. Don't forget to include upgrading insulation, but make sure that isn't done before you have any HVAC work done in the attic that may be suggested.
    Thanks for the help, like I said, I was just wondering what affect this would have. In time I will have to look into putting a return through the chimney.


    MP

  10. #10
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    Jan 2008
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    120
    Gary_G,

    I went with the great carrier model as I was sold on the features and benefits and the contractor came in well below the 6 other bids I had received.

    Other bids were received on Tappan, Bryant, Comfortaire, Gibson, Trane, and Lennox.

  11. #11
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    Quote Originally Posted by chucko615 View Post
    "You bet", "Great Idea". What was the question again
    Hey thanks this what I wanted to hear.

  12. #12
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    Cedar Grove, Wi-Sheboygan
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    If you were to put a whole house fan in your attic it will only suck the cool air from the first floor and it will suck it all from the first floor and once it has done that your AC will only run to satisfy the whole house fan due to the fact that once the fan has created a air flow from the first floor the cold air from your downstairs duct will flow directly to the air flow the fan has created rendering the fan useless, but you will definately have air movement Your best bet would be to get some high wall returns in your upstairs bedrooms as well as some cold air returns on the floor, it will be moeny well spent once you have them in and operating. I will tell you what I have doen in my home, I have a chimney which became abandoned after installing a new direct vent hot water tank which I knocked the chimney down to just above the attic floor and capped it off for the time being until I have time to run some high wall returns, any way once you have the chimney capped off knock a hole as large as you can get into your chimney at the base a couple of inches off the floor and one just below the ceiling and put the proper vent covers on them, now go into your basement and knock a hole in the chimney and connect the chimney to your return drop from the furnace and seal it good and you will notice a difference once everything is connected. for the summer close the bottom return vent and let the furnace pull the hot air off the ceiling down the chimeny which is your return air chase and in the heating season close the ceiling and open the floor vent. Prior to making your final connection to the furnace I would clean the chimney out really good and put a cheap filter in your furnace and run the furnace on high for a couple of minutes just to suck any loose particles out of the chimney and then replace with your normal filter and run as you normally would with the fan on continuous run mode on low speed. Much better than a whole house fan!!!

  13. #13
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    Quote Originally Posted by DanW13 View Post
    If you were to put a whole house fan in your attic it will only suck the cool air from the first floor and it will suck it all from the first floor and once it has done that your AC will only run to satisfy the whole house fan due to the fact that once the fan has created a air flow from the first floor the cold air from your downstairs duct will flow directly to the air flow the fan has created rendering the fan useless, but you will definately have air movement Your best bet would be to get some high wall returns in your upstairs bedrooms as well as some cold air returns on the floor, it will be moeny well spent once you have them in and operating. I will tell you what I have doen in my home, I have a chimney which became abandoned after installing a new direct vent hot water tank which I knocked the chimney down to just above the attic floor and capped it off for the time being until I have time to run some high wall returns, any way once you have the chimney capped off knock a hole as large as you can get into your chimney at the base a couple of inches off the floor and one just below the ceiling and put the proper vent covers on them, now go into your basement and knock a hole in the chimney and connect the chimney to your return drop from the furnace and seal it good and you will notice a difference once everything is connected. for the summer close the bottom return vent and let the furnace pull the hot air off the ceiling down the chimeny which is your return air chase and in the heating season close the ceiling and open the floor vent. Prior to making your final connection to the furnace I would clean the chimney out really good and put a cheap filter in your furnace and run the furnace on high for a couple of minutes just to suck any loose particles out of the chimney and then replace with your normal filter and run as you normally would with the fan on continuous run mode on low speed. Much better than a whole house fan!!!

    Ok, this is getting a little clearer. When I had initially thought about using the chimney as a return I thought I would have to put a type of a liner inside. If I can cap it off and just use it I think I can accomplish that no problem.

    Couple questions at ya. Im trying to grasp you directions and printed them off. First here is what I have pictured, get the chimney capped off at least where I can as I have about 10 foot of chimney still up in attic so kind of tough, now I was thinking of knocking a hole in chimney near the floor in the upstairs.... and then basically putting a grate on it as a return. And then in basement tie into it and hook up to return.
    Guess my question is, what is a high wall return?

    Thanks much

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