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  1. #1
    I apologize in advance for the book but all info is pertinent I think:

    My contractor will be moving earth on my new house in the next 2 weeks. He is a great guy with a sterling reputation as a builder and has structured our deal in a way that helps me out quite a bit.

    I say all of that because I am wondering about his current plan for my HVAC but I don't want to seem like I am grilling him over every detail. Therefore I am hoping to get some input here.

    House is 1.5 story traditional with brick siding, approximately 1600 sq ft on main floor, 900 on second floor and about 600 sq ft of the basement will be finished. The family room and foyer are 2 story.

    His HVAC sub uses Lennox equipment and he expects to use a 3 ton 13 seer AC unit along with a 90% effeciency furnace for the main floor and basement and an 80% effeciency furnace with a 2 ton 13 seer AC unit for the second floor.

    He is planning on a return in the basement area (along with the main floor of course) and he said he would install manually controlled dampers.

    This will not be a walkout basement. There will be 10 foot poured concrete walls and he is planning for exterior drainage to a sump with a pump.

    This location is southern Kentucky. Pretty hot and humid summers, mild to occasionally cold winters.

    Does this situation raise any red flags pertaining to humidity control or indoor air quality in the basement?

    thanks in advance for any comments,

    jho


  2. #2
    Join Date
    Apr 2002
    Location
    Pottsboro TX
    Posts
    181

    Basement

    Like all subsurface structures that become living space, those basement walls should be (water proofed) and insulated on the outside and the basement floor should have a moisture barrier (visqueen) under it. Level of waterproofing sophistication depends on amount of water movement through subsoil and the (water table). A sump pump will remove water that penetrates to your basement . . . BUT . . . .don't expect moisture and humidity won't be present in the basement. Insulation and moisture barrier will have to be installed on the inside too. Only then can the basement be heated and air conditioned like the rest of the house.
    Phil

  3. #3
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    insulate at least 2 ft below grade [& all above grade] any exposed insul must be covered to be UV resistant.

    drain must be below the foundation

    read at BUILDINGSCIENCE.com

    ask just how deep vertically the return & supply trunks will be -- you may wish to add 1 foot more to have more head room -- easy now, hard later.

  4. #4
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,428

    RH Concerns

    Originally posted by jhomeowner
    House is 1.5 story traditional with brick siding, approximately 1600 sq ft on main floor, 900 on second floor and about 600 sq ft of the basement will be finished. The family room and foyer are 2 story.

    His HVAC sub uses Lennox equipment and he expects to use a 3 ton 13 seer AC unit along with a 90% efficiency furnace for the main floor and basement and an 80% efficiency furnace with a 2 ton 13 seer AC unit for the second floor.

    He is planning on a return in the basement area (along with the main floor of course) and he said he would install manually controlled dampers.

    This location is southern Kentucky. Pretty hot and humid summers, mild to occasionally cold winters.

    Does this situation raise any red flags pertaining to humidity control or indoor air quality in the basement?
    Basement should be fully conditioned,
    not just the 600 Sq. feet which will be finished.

    Is the 3-ton adequate to handle the 1,600 S.F first floor and 1,600 Sq. Foot basement?

    Is the 2-story family room cooled with the upstairs unit?

    Need exact answers ? __
    see my credentials / contact info or
    review the ACCA Manual J calc that
    your builder / mechanical contractor
    has provided you for this unique house.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  5. #5
    Thanks so much for the replies. The sump will be located outside the basement area and the drainage will be below the basement.

    I'm pretty confident that the proper insulation and drainage for my area will be used.

    I think I will try to find out who the HVAC sub is and have someone else call them and ask them if they do a manual J-calc on jobs like this.

    On a side note, is there a place on the internet you can read an explanation of how these systems work? I know you guys talk about compressors and air handlers and lots of things I can guess the meanings behind, but it would be nice to read a short primer on how heating and A/C systems work.

    thanks
    jho

  6. #6
    Join Date
    Mar 2005
    Location
    Indiana
    Posts
    66
    A heat load calculation definitely needs to be performed!

    Try http://www.howstuffworks.com for an explanation of how air conditioning equipment works.

  7. #7
    Join Date
    Sep 2004
    Location
    Georgia
    Posts
    103
    The University of Minnesota Extension Service has a nice 4 part series on basement moisture. Its an easy read and covers the causes and solutions.

    Here's the link:

    http://www.extension.umn.edu/distrib...s/7051-01.html

    Good Luck,
    Dryguy

  8. #8
    Join Date
    Apr 2002
    Location
    Pottsboro TX
    Posts
    181

    Basements

    Dryguy,
    That's the best layman's explanation with pictorials I've seen anywhere. The information and technique will not always agree with that from southern climates and soil conditions but the basics are right on.
    Phil

  9. #9
    Join Date
    May 2002
    Location
    Colorado
    Posts
    697
    To keep your basement from being cold during the AC season, it is absolutely essential to insulate and throughly seal ALL ducts that run in the joist bays.

    Also, if you don't want the 2nd floor to be HOT in the summer, make sure the ducts that feed that floor are amply sized. They rarely are. Before you accept the house, test ALL the supply outlets for air floor; they should all have about the same velocity.

  10. #10
    So I need to make sure that even the lines that go out from the trunk line are insulated?

    What about the ones that vent into the basement area?

    I believe he is planning on conditioning the whole basement, but only having a single return on each floor. Will that cause me a problem?

    thanks,
    jho

  11. #11
    Join Date
    Apr 2002
    Location
    Pottsboro TX
    Posts
    181

    Dash, help this man

    Jhomeowner,
    I think you'll find that almost ALL installers here would have wished for a return in EVERY (ROOM) not just on every floor or level.
    "Dash" is THE ductman on this site.
    Phil

  12. #12
    Join Date
    Jul 2008
    Posts
    17
    You definetly need a load calculation done to find the proper size of unit you will need. Also zoning would be a great choice for your home. That way you can keep each zone at the same temp. That would eliminate the cold basemet for the mix.

  13. #13
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,637
    Quote Originally Posted by jhomeowner View Post
    I apologize in advance for the book but all info is pertinent I think:

    This location is southern Kentucky. Pretty hot and humid summers, mild to occasionally cold winters.

    Does this situation raise any red flags pertaining to humidity control or indoor air quality in the basement?

    thanks in advance for any comments,

    jho
    Is the home going to be air tight? Who is in charge of fresh air ventilation and keeping the basement dry during wet cool weather? This is about comfort and IAQ, any interest? Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

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