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  1. #1
    Join Date
    Jun 2014
    Posts
    14

    Picking the right system - load, capabilities and expandability

    Need help picking the right system based on load, capabilities and expandability.
    Heating Load: 46,500 BTU @ Design Temp of 0*
    Cooling Load: 3.5 ton @ Outside temp of 93* and Indoor temp of 74*
    Thanks Dan! for doing the calculations and providing great input on how to interpret these numbers.
    I’m debating between the following systems.

    Bryant Evolution
    987MA60080 ­ 98% Modulating 80k furnace 127ANA036 ­ 2 stage 3 ton air conditioner
    Pros ­
    1. Great communicating system ­ Shows static pressure etc, make my inner geek happy.
    2. Better prepared for zoning down the road ­ we have a tri­level townhome and might need zoning to address the temp difference between floors.
    Cons ­
    80k is quite oversized for the 46k load, and the installer is reluctant to put in 60k, saying that the load should be based on a design temp of ­10* for Chicago.

    Lennox iComfort
    SLP98UH070XV36B ­ 98% Modulating 70k furnace
    XC1603623003 ­ 2 stage 3 ton air conditioner
    Pros ­
    1. 70k furnace is closer to the load.
    2. Good communicating system ­ can modulate up and down. 3. 10 year parts and labor warranty
    4. Like the look of the A/C unit.

    Cons ­
    1. Read something about difficulty of getting parts.

    Questions
    1. Is the 10k difference between 70k and 80k furnace big enough to be a factor in the decision? At 35%, the difference is down to 3500 BTU.
    2. I’ll save about 10% of the total by going with a single stage A/C. Would like to hear your thoughts ­ is there a noticable difference in comfort. I am in Chicago.

    Both installers are pretty well known and have good reviews. Neither did a load calc though.

    Any other diffs between the system that I should consider.

    Thanks!

  2. #2
    Join Date
    Jun 2014
    Posts
    14
    Would appreciate any input I can get to decide between these two systems. Thanks

  3. #3
    Join Date
    Mar 2006
    Location
    The South
    Posts
    2,240
    One thing that stands out to me. Relatively small heating load compared to large cooling load.

    Tell us about your home's size in living area as well as your location.

    IMO

  4. #4
    Join Date
    Jun 2014
    Posts
    14
    Quote Originally Posted by tigerdunes View Post
    One thing that stands out to me. Relatively small heating load compared to large cooling load.

    Tell us about your home's size in living area as well as your location.

    IMO
    Hi Tigerdunes,

    Here is the load calculation worksheet that Dan had put together based on the information I provided regarding the insulation and Glass R values etc.

    Here is my post with more information about the house...
    http://hvac-talk.com/vbb/showthread....n-past-usage#8

    Thanks!

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