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Thread: New house build

  1. #1

    New house build

    Getting a new home built in atlanta, ga area and will be doing 5.5" open cell icynene attic, 3.5" whole house otherwise, including exterior basement walls. Foundation walls will get normal fiberglass insulation.

    Any cons to doing this blown insulation? It will be covered 10 year home warranty.

    I asked builder to upgrade upstairs and main level furnaces to 90% from 80, and 2 ac system to 16 seer. The choices are:
    Amana ASX 16 $
    Trane XLI 16 $
    Lennox XC 16 $

    I don't know why, but I read allot of dismissing on xl 16i... Why is that? Also read trane over Lennox, and can't find too much about Amanda.

    Would these upgrades be worth it from the 13 seer builder grade Lennox or trane system included?
    Last edited by BaldLoonie; 11-10-2012 at 05:41 PM.

  2. #2
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    3,164
    no pricing allowed as per site rules.
    mods will be along shortly to edit out your prices.

    are you sure that 5.5 inches of open cell meets code R-values?
    here in La. our code mandates R25 for cathedral ceilings which would
    be 6-7" of open cell. at minimum you want foam to fill rafter bays
    and cover faces of rafters to mininize thermal bridging.

    putting foam sheathing to exterior of walls, taping seams and making
    this the air barrier is a better use of insulation monies for walls.
    conventional insulation in walls and air tight drywall approach for
    interior of walls completes the air seal of walls. that the air movement
    through the insulation is sealed on both sides, allows the insulation
    in walls to perform as spec'd.

    upgrading from 13 to 15-17 SEER is also a good investment.
    above 17 SEER the payback isn't always worth the investment cost.

    looking at brands like Goodman(amana's second brand)
    -American Standard(trane's second brand)
    will give you more information as to pricing.
    same equipment..

    investing in correctly sizing the hvac system is always a good move.
    rather than sq ft per ton sizing.
    bigger units aren't the better investment. in summer oversized
    a/c doesn't run long enough to remove humidity.
    cost is more upfront for oversized equipment, and cost to
    operate is more.

    spend some time educating yourself before making these
    decisions that effect your comfort every day.

    best of luck.
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  3. #3
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    The upgrade to 2 stage will be worth it for comfort in a humid area like yours. A foam house will need ventilation. I'd suggest a ventilating dehumidifier on the upstairs unit. Make sure the load calcs are doen correctly. A foamed house will outperform the load calcs in soem cases. Unlesss its' a very large home, the sytem will be very small. do not oversize. The home will be humid and muggy and electric bills will be higher.

  4. #4
    how would they do the load calc of the spray foam if the house has to have the AC unit already installed before the foam starts? I'm the only house doing full spray in, another house had only the attic done with my floor plan.

    Thanks!

  5. #5
    Sorry i just didn't think you could ask for price quotes

    The builder is definitely to code. This will be my 3rd house from this builder

    1st: 6 year old home, 2100sqft, no basement, 13 seer single dual zone 3 ton unit wrapped and insulated peak electric bill $150, average $100
    2nd:12 year old home, 2600sqft, full finished basement, unknown insulation, 2 2 ton, one 1.5 ton units, 12 seer, peak electric bill $400, average $200

    It's obvious the change in codes between the two houses made a huge difference.

    according to this http://www.colemanac.com/homeowners/...ur_savings.asp
    in my zone 3 i will be $200/month saving from 13-18 seer on 2100sqft new house is 3000sqft with spray foam, so i assume it will balance out.

  6. #6
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    3,164
    load calcs are done from plans, using builder inputs from plans.
    things like R-value of insulation, shgc & ufactors of windows
    orientation, overhang, infiltration are all entered into software
    program that sizes hvac system.
    foam shows up in two places in load calc. R-value & air tightness.
    both can be achieved in various ways.

    in my software program when you enter in actual cost
    of foam in both walls and rafters payback is more than 20 years.
    to foam roofline cuts payback in half.
    air sealing walls can be achieved without foam insulation.

    best of luck.
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  7. #7
    Does it seem odd the Amana unit is 1/2 the price of the others? I just can't justify a Trane or Lennox for double the price

  8. #8
    Join Date
    Mar 2008
    Location
    N Texas
    Posts
    69
    I think you will also find that the std warranties with the Amana system will be FAR SUPERIOR to those of the other two you mentioned. That said, proper design and installation of any system selected will ultimately determine your level of comfort and any efficiencies.

  9. #9
    You guys are so helpful, thanks for the advice. I have done industrial AC installs at my Employers, but tapping into the whole residential thing is has proved my ignorance.

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