Results 1 to 8 of 8

Thread: Sealed Envelope

  1. #1
    Join Date
    Jan 2006
    Location
    Bryant AR.
    Posts
    163

    Thumbs up Sealed Envelope

    This is the coolest thing I have ever seen...3.5 ton system holding a 73 degree temp in 100+ degree weather on 2500 square feet with 10% outdoor air.
    The house was foamed from the foundation to the crown of the attic. every exterior wall and celing were foamed and there was NO other insulation in the attic!!! AND it was 78 degrees in the attic!!! Like I said, "the coolest thing I have ever seen"
    After finding out our second born was also a boy, my wife asked "why are you sooooooo happy" to which I replied; "2 of those things are easier to keep up with than 20,000!"

  2. #2
    Join Date
    Apr 2002
    Posts
    11,808
    Good job

    Pretty simple keep the heat and humidity out
    The way we build has a greater impact on our comfort, energy consumption and IAQ than any HVAC system we install.

    http://www.ductstrap.com/

  3. #3
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    That is impressive. Almost sounds like the unit could be a little oversized even.

  4. #4
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,451
    Quote Originally Posted by trixter View Post
    This is the coolest thing I have ever seen...3.5 ton system holding a 73 degree temp in 100+ degree weather on 2500 square feet with 10% outdoor air.
    The house was foamed from the foundation to the crown of the attic. every exterior wall and celing were foamed and there was NO other insulation in the attic!!! AND it was 78 degrees in the attic!!! Like I said, "the coolest thing I have ever seen"
    How cfm of fresh air is this and what is the duty cycle of the a/c? How long have you been doing this? 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"

  5. #5
    Join Date
    Jun 2001
    Location
    DFW
    Posts
    684
    Quote Originally Posted by trixter View Post
    This is the coolest thing I have ever seen...3.5 ton system holding a 73 degree temp in 100+ degree weather on 2500 square feet with 10% outdoor air.
    The house was foamed from the foundation to the crown of the attic. every exterior wall and celing were foamed and there was NO other insulation in the attic!!! AND it was 78 degrees in the attic!!! Like I said, "the coolest thing I have ever seen"
    Spray foam is not the only way to get there and depending on the installer is not a guaranteed answer.

    A sealed envelop with the duct work and air handler inside takes care of some of the major issues. One more important issue is shading the windows in the summer.

    My own house is 4,000 sq. ft. with a 2 ton heat pump. It hit 103 degrees over the weekend and the house stayed at a constant 74 degrees. I looked at spray foam, but I found other answers that made more economic sense for my particular house.

  6. #6
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,347
    102 at my place on Sunday, not far from Paul's. ~R40 (I really need to measure to see just what it is) attic floor insulation, spray-on radiant barrier (which isn't the best choice, I've measured, but better than nothing), new thermally improved patio doors and glass, ceiling penetrations to attic throughout entire house sealed as much as practical. Held 75 degree setpoint with 44% relative humidity on 1,800 square feet single story structure with three ton condensing unit on the ground. Not as impressive as cooling 4,000 square feet with 2 tons, but for a fifty year old house, I'll take where I'm at vs. how so many homes of its vintage and newer perform in my climate without the thermal boundary improvements.

    Foaming the roof deck and leaving the HVAC equipment and ducts in the attic takes the idiocy out of placing HVAC equipment and ducts in an attic. Otherwise it is complete insanity to put the stuff up there with conventional configurations.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  7. #7
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    3,188
    I've found that while air tightness is quickly achieved with foam insulation, (in
    most cases) the same level of tigheness can also be achieved with conventional insulations and that old attention to detail.
    Things like sealing the sole plate, incorperating air tight drywall approach,
    ICAT recessed lights and sealing all holes..wire penetrations, plumbing penetrations.
    It is easier to build with this in mind, but existing homes can also achieve
    'tight', just cases of caulk applied to areas like ceiling moldings, floor moldings
    plumbing penetrations etc.
    Harder on existing homes..but achievable.
    Congratulations folks!!
    I sure wish that hvac salesman I met today could read this
    it might would make him re-think 5 tons on 1750 sq ft!

    We really need to have a forum here on houses as a system...
    (hint hint)
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  8. #8
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,347
    Quote Originally Posted by energy_rater_La View Post

    We really need to have a forum here on houses as a system...
    (hint hint)
    I second that...heartily. Perhaps titled "Residential Building Science, Energy Efficiency, and Comfort"?
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event