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  1. #1
    Join Date
    Jul 2008
    Posts
    5

    not too familiar with dual fuel system

    I have to replace a 2.5 ton a/c & gas furnace. Heating load done =23,228 & cooling load = 27,206. 1500 sq ft ranch with small room over attached garage. I live in SE VA with relatively mild winters & sometimes hot summers.
    I got estimate for 2 units:

    York Affinity 3 ton a/c 15 seer, 80k btu 80% modulating gas furnace. Honeywell prog t-stat, lifetime warranty on compressor & 10 yr parts & labor. i believe he said it was a 2 speed a/c which I was told would help with short cycling. I wondered if this unit may be oversized, but I was told .5 ton is not that big a deal and the 2 speed would help with short cycling.

    York Latitude 2.5 ton a/c 14.5 seer, 80k btu 80% single speed gas furnace. same t-stat, 10 yr warranty on compressor, 5 yr parts, 1yr labor.

    Then I was told by someone i know that I should look into a dual fuel system-- heat pump with gas furnace back up. Now I don't know what to do.

    Any suggestions? Pros & cons?

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,875
    3 tons would be a bit much by your cooling load.

    A dual fuel can save you money on your heating bill. The heat pump would do the heating during the mild temps. say 35 and above. The gas furnace would take over below that.
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  3. #3
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,043
    Yea, definitely look into dual fuel in your climate.

    Oversizing 2 stage units means you are buying an expensive single stage. Since the 2 stage scroll systems tend to run about 75% on low, you'd never get above low except during a cool down. If you really want 2 stage equipment, best would be look at a model (Bryant/Carrier 16 SEER or A-S/Trane 18/19 SEER) that have 2.5 ton units. Or take the money you save buying a single stage over a 2 stage and put it into dual fuel where you can really get a payback.

  4. #4
    Join Date
    May 2007
    Location
    DC Metro Area (MD)
    Posts
    3,371
    With that heat loss, 80k is too much heat. York makes a 60k mod. Are you sure the heat loss is accurate? As others have said, the 3-ton Affinity wouldn't be the best option with that heat load because it would cycle on and off in low stage even at design conditions with that heat gain. The 2.5-ton Affinity 13 SEER unit would be a better choice in my opinion--along with a properly-sized furnace.

  5. #5
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,043
    I didn't even address the grossly oversized furnace. Really need something with a 40K input, even if you can't get 2 stage that small.

  6. #6
    Join Date
    Jun 2008
    Posts
    80
    Quote Originally Posted by RyanHughes View Post
    With that heat loss, 80k is too much heat. York makes a 60k mod. Are you sure the heat loss is accurate?
    My thoughts exactly!

    Ask for the cooling capacity of the proposed A/C units so you can be sure they're matching close to the cooling load.

    I would think about a heat pump also.

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