Results 1 to 7 of 7
  1. #1
    Join Date
    Apr 2003
    Location
    Northern Virginia, Fairfax County
    Posts
    641

    Question Smallest Central A/C or Heat Pump with Lowest Capacity

    Hello everyone, my last post was in Jan 2007. Now I'm back for a new project, and it's great to see some of the old names here. We do not yet have a good, professional load calc on an architect's design, but we need to chose some good options.

    Can a nominal 1 1/2 ton A/C or heat pump be set up to work at a capacity much less than 18,000 BTUH? Is 12.000 or 15,000 BTUH a reasonable target? If so, what specific models would you recommend for compressor and evaporator coil? We are thinking primarily Trane or Carrier, including gas furnace or hybrid heat pump/gas furnace, but also looking for any other good solution.

    This is for an expansion of my son's split level house in Northern Virginia. The problem is the new space "feels" like it is too small for the smallest central A/C or heat pump, and one of the bidders for the remodeling threw up a yellow flag. My own "rough," non-professional load calc comes out at 11,100 BTUH cooling with +/-600.

    The house has three levels. The main entrance is to the middle level living, dining, kitchen, with its own attic, and there is a den expansion behind that. The lower level to the side and half flight down is two rooms, bath, and utility space. The upper level also to the side and directly above the lower level is three bedrooms and a bath. The new expansion will be above the middle level replacing the attic at 480 sq ft (20 x 24) consisting of a bedroom, bath, and maybe a walk-in closet.

    The current HVAC includes a two-stage Trane XL-19i A/C and two-stage Trane gas furnace. This may have the capacity to handle the new bedroom area, but some remodeling contractors get nervous about the modifications to existing structure. The furnace is in the utility space, really a long, narrow closet on the lower level, shared with washer, dryer, and access to crawl space under the middle level. Although the closet shares its wall with the middle level, running a new trunk straight up through a bedroom and over to the new bedroom's attic would be a challenge. Also, we know there is a challenge in balancing air flow to four different levels of a house.

    By the way, that load calc for 11,100 comes from the Consumer Reports web site tailored for room air conditioners. I was looking only at total space involved.

    We appreciate all the help.

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,786
    York has a 1 ton A/C.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  3. #3
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    33,396
    I put one of those little suckers with 5kw heat in for a friend to live above her daughter's garage. Worked great. Hardly noticed any increase in the juice bill, winter or summer. Otherwise, 18,000 BTU is 18,000 BTU and if 11K is needed, that's well oversized. See what the heat needs are, chances are a gas furnace would be way too big.

  4. #4
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    Ductless split, aka minisplit
    If more government is the answer, then it's a really stupid question.

  5. #5
    Join Date
    Mar 2004
    Location
    SE Michigan
    Posts
    17,599
    Looky here...


    "The road to Hell is paved with progressive policies."

  6. #6
    Join Date
    Apr 2003
    Location
    Northern Virginia, Fairfax County
    Posts
    641
    Quote Originally Posted by beenthere View Post
    York has a 1 ton A/C.
    Does anyone know of other brands at 1 ton? I posted a separate item on duct-less units:
    http://hvac-talk.com/vbb/showthread....00#post1865600

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,786
    York is the only one that has a 1 ton central.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

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