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Brad White_64
Brad White_64 Member Posts: 11
Your design temperature is either 0.4% or 1%, meaning you have some wiggle room for more extreme weather, Jeff. And the humidity index, (I know, I know,...it's not the heat.... blah blah...)

Where are you located? I can post the weather data for near you; the "median of extreme highs" probably is higher or close to what you may be expecting over the next few days.

But attics? Yeah, you right!

Maybe it is sundress weather? :)


  • Jeff Lawrence_25
    Jeff Lawrence_25 Member Posts: 746
    Our design is 92 degrees

    Will it be too warm here?

    Weather.com says that the highs today (3 July 2006) will be 96 degrees and tomorrow (4 July) will be 98 degrees. These will be the highest temps here in at least 3 years.

    I'm going to have to stay out of the attics.

  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    I measured 101.7 yesterday on the north side. Supposed to be just as hot today. Fortunately dewpoint is "only" in the upper 60s, not the 70s as common this time of year.

    Summer design temp here is 95° and I use 120 grains of moisture. A/C systems definitely working hard and there's no way you'd find me in an attic or on a dark roof!
  • Jeff Lawrence_25
    Jeff Lawrence_25 Member Posts: 746
    You won't see me in a Sun Dress

    I'm located in the metro Atlanta, Georgia area, 33 degrees latitude.

    My 7th edition of the ACCA manual J book shows that the two and a half percent design is 92 degrees (db) and the coincident design (wb) is 74 degrees. The grains difference is 27 at 55% and 34 at 50%.

    Current conditions at my house are 74.2 wb and 96 db from my digital sling psychrometer from a Rh of 36%

    The amazing thing is that my own house won't maintain a 75 degree setpoint. Looks like I have a bit of work to do.

    Whew, it's gonna get busy.
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    My conditions here sound very similar (but I don't have a sling psychrometer--digital or otherwise).

    Am only running the A/C for the attic (rented) and master suite on 2nd floor right now. Master suite A/C is oversized (2½ tons for about 750 sq.ft. plus one open staircase to ground floor). Haven't been here at night so do set up. Both yesterday and today I got to work at about 5:00 a.m. Inside temp 82°. Set thermostat to 76° and it ran constantly until I left at about 5:00 p.m. with inside temp 77°. Similar today. Up to 95.7° out (11:50 a.m.), Unit hasn't stopped running and temp at thermostat just reached setting of 76° but unit hasn't stopped. Comfort is fine.

    BTW the real bedroom of the 5-room suite has the thermostat and it's designed to stay about 2° cooler than the office and sleeping porch and about 1° warmer than the two bathrooms. Office where I am right now is 78°. Both baths are 75°.

  • Brad White_91
    Brad White_91 Member Posts: 25
    78 in the office?

    Mike- I think you need to turn down the TRV's there buddy. I know you love running the Vitodens but please... it is summer.. For the love of God... :)
  • Brad White_91
    Brad White_91 Member Posts: 25
    I am with you Jeff

    save the sun dress for indoors, after hours. No need for anyone to know. :)

    Here is the weather data

  • Brad White_91
    Brad White_91 Member Posts: 25
    I agree Jeff

    wear it with abandon, but indoors only :)

    Here is the Atlanta weather package with a 0.4% design of 94 degrees (75 wet bulb) and a 1% design of 92 degrees (74 wet bulb).

    Your "median of extreme highs" is 97 degrees so nothing extraordinary there, but that goes with a corresponding mean wet bulb temprature of 75 degrees which is fairly brutal when coupled with a 97 degree dry bulb.

    Taking a shower rules. Stay cool.
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    On any given day I'm likely to be working either outside or non-AC space as well as in the office. Can't let myself get too cool or it makes the rest worse! Ceiling fan on medium-high and A/C coming from the ceiling (where it belongs) helps greatly...

    98.5° now and the A/C still hasn't stopped running since I turned it on at 5:00 a.m...
This discussion has been closed.