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  1. #53
    Join Date
    Jul 2007
    Location
    Delaware
    Posts
    3,824
    You have two manual J's done. One is for a 2-Ton & the other for 2.2 Ton. The 2.2 bumped it up to 2.5. What is the temp (high) that this MJ was based on? How many days out of the year will you hit that temp? How many coolings days/hours do you have where your home is?
    Always here

  2. #54
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    4,275
    Quote Originally Posted by jtrammel View Post
    With a smaller unit that removes more humidity you may be more comfortable at 72-74. Humidity has more to do with comfort than temperature.
    +1
    The 2 ton may not hold 68-70 during the hottest afternoons but the humidity will be low making it feel cooler. 68-70 at low humidity and fans running is very cool to most people.

  3. #55
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,728
    Quote Originally Posted by 54regcab View Post
    +1
    The 2 ton may not hold 68-70 during the hottest afternoons but the humidity will be low making it feel cooler. 68-70 at low humidity and fans running is very cool to most people.
    Are you sure the stat is accurate? I find 78 at 40 rh is comfortable if I'm inactive, and I need 75 if rh goes above 45%. Above 50% rh, pretty hard to get comfortable without feeling clammy. You definitely want to build an understanding of how RH factors into your comfort requirements.

    I've found weight can impact tstat settings. As peoples % body fat levels increase their comfortable temperatures decreases, so things start to get delicate here, but you don't want to dismiss someone's stated setting without being cognizant of this important variable.
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

  4. #56
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,287
    Quote Originally Posted by tedkidd View Post
    Are you sure the stat is accurate? I find 78 at 40 rh is comfortable if I'm inactive, and I need 75 if rh goes above 45%. Above 50% rh, pretty hard to get comfortable without feeling clammy. You definitely want to build an understanding of how RH factors into your comfort requirements.

    I've found weight can impact tstat settings. As peoples % body fat levels increase their comfortable temperatures decreases, so things start to get delicate here, but you don't want to dismiss someone's stated setting without being cognizant of this important variable.
    I've found that some people have Bigger Boilers [ internal, of course], so preference for 73'F or 78'F depends on boiler efficiency
    and -Bigger is not Better- can be applied in a few different ways.

    I have a big boiler but also find that 78'F at 40% R.H. is just fine!
    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. #57
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,287
    Quote Originally Posted by 54regcab View Post
    +1
    The 2 ton may not hold 68-70 during the hottest afternoons but the humidity will be low making it feel cooler. 68-70 at low humidity and fans running is very cool to most people.
    Dry Bulb 68'F
    Wet Bulb 58'F
    Dew Point 51'F
    Humidity 55%
    which is good performance from DX system in most of the U.S. at less than 3,000 foot elevation
    would probbly be considered clammy by most people.

    I would Not refer to this condition (> 42%) as Low Humidity.

    I don't know of any normally used residential equipment that actually achieves <43% at 68'F.
    Last edited by dan sw fl; 10-09-2012 at 06:07 AM.
    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

  6. #58
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    Quote Originally Posted by tedkidd View Post
    Are you sure the stat is accurate? I find 78 at 40 rh is comfortable if I'm inactive, and I need 75 if rh goes above 45%. Above 50% rh, pretty hard to get comfortable without feeling clammy. You definitely want to build an understanding of how RH factors into your comfort requirements.

    I've found weight can impact tstat settings. As peoples % body fat levels increase their comfortable temperatures decreases, so things start to get delicate here, but you don't want to dismiss someone's stated setting without being cognizant of this important variable.
    +1. At our house, dewpoints are under 50F all summer, so 73-75 iis very comfortable. Downstairs dewpoints are in the low 40's so 77F feels comfortable. However, when I go to my parents house wiht their oversized AC (2.5tons on a 1400sqft 2 story townshouse with 2 shared walls in Michigan (probably needs 1.5 tons based on run times alone) the humidity is over 55% and it needs ot be 69-70F ot be comfortable.

    Sorry, but 68F is either clammy if RH is over 50%, or cool if it's <50%. 68F is my winter setting in my home.

    WHat I find funny, is that some people will keep it 69F in summer and 71F in winter. Now there is a clear sign that humidity is not being managed. Heck, I had a roomate that wanted 70F in summer but I came home ot hte huse at 76F in winter.... and the dumba** is in shorts and a T-shirt.

  7. #59
    Join Date
    Jul 2012
    Location
    Western KY
    Posts
    1,221
    Quote Originally Posted by Zomby View Post
    Wow. Simply wow!.

    The American Standard contractor rep came out today and did pretty much the same walk-thru, testings, calculations, etc. His price was WAY over what the Trance contractor rep quoted... I mean WAY over.

    From what I can tell the quote is for the exact same equipment, but he said I needed a 2.5 ton because we like to keep the house cooler than normal. The Trane rep said 2 ton, but I didn't tell him we liked to keep it around 68-70 degrees in the summer.

    Next up. A Bryant contractor...........
    Sooo a second quoat did not produce the devil? Forget the price for now. Look at the load calcs. Very close. So now you should be comfortable in knowing what you need, tonnage wise. Get the 3rd quoat then pick the one you want based on solid data. Too easy.

  8. #60
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    4,275
    Quote Originally Posted by motoguy128 View Post
    +1. At our house, dewpoints are under 50F all summer, so 73-75 iis very comfortable. Downstairs dewpoints are in the low 40's so 77F feels comfortable. However, when I go to my parents house wiht their oversized AC (2.5tons on a 1400sqft 2 story townshouse with 2 shared walls in Michigan (probably needs 1.5 tons based on run times alone) the humidity is over 55% and it needs ot be 69-70F ot be comfortable.

    Sorry, but 68F is either clammy if RH is over 50%, or cool if it's <50%. 68F is my winter setting in my home.

    WHat I find funny, is that some people will keep it 69F in summer and 71F in winter. Now there is a clear sign that humidity is not being managed. Heck, I had a roomate that wanted 70F in summer but I came home ot hte huse at 76F in winter.... and the dumba** is in shorts and a T-shirt.
    We see it all the time. People want to program their thermostat that way!! Ask the customer, if it's 73 in the house, do you want to heat or AC to run? Their answer is it depends on time of year !!

  9. #61
    Join Date
    Sep 2012
    Posts
    71
    Hey guys, if I decide to go with the Trane XR15 and the Trane XV95 - Is there a certain Trane thermostat I should make sure they install?

  10. #62
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,728
    Acculink.
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

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