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  1. #1
    Join Date
    Apr 2014
    Posts
    51

    Default A/C - Ductless system vs portable unit

    Trying to decide whether to install a ductless A/C system versus just using a portable a/c unit - the kind that vents out the window with a hose. The ductless system with the install is @ 4 - 5x more expensive than the portable unit plus a lot more annual maintenance. I hear that portable units are easy to use but are noisy. I've seen mixed reviews. Looking to cool a small summer cottage near the beach. I don't know anyone who has used a portable unit so can't compare with the full system. The portable unit would have to be large. I know that I don't want window a/c units. Sometimes we rent out this cottage and sometimes we don't. For the times we do rent it out we want the least hassle option. For the times that we don't we want to make sure that the a/c isn't running when no one is there. If cost was no object then I wouldn't hesitate and go with the ductless system but I'm trying to figure out if a portable unit is worth the savings or if it's too much hassle.

  2. #2
    Join Date
    Feb 2008
    Posts
    206

    Default Re: A/C - Ductless system vs portable unit

    First, what is the total square footage of the cottage you are trying to cool, and do you have adequate amps at the main elec panel to accomodate the AC?

    And does it have a mostly open area that can be cooled with a single unit?

    Google "sizing a residential AC"

    Google "mini-split air conditioners" to view perhaps the most popular ductless type of AC used for this application.
    Sanyo mini-split
    Mitsubishi mini-split
    Fujitsu mini-split
    Samsung mini-split
    Friedrich mini-split
    http://ajmadison.com/air-conditioner...r-conditioners

    And numerous others---the compressor is installed outside & only the cooling unit is brought indoors via a freon line so there is no noise inside the house; be advised that a licensed AC technician usually has to install these, since the freon line has to be "charged" with freon using special equipment as part of the installation (check local codes in your locality), which means added cost.

    Another option is a thru-the wall AC that is less expensive than the mini-split, & will cool the whole cottage (especially if it is of open-space design), but is noisier than the mini-split; a thru-the wall AC can usually be installed by the homeowner, providing you have adequate amps at the main elec panel.

    Amazon.com and others sell both ductless & thru-the-wall units at competitive prices & often without local sales tax applied, and sometimes free shipping, but you may have to call a pro to install a mini-split, which is an added expense.

    Also consult the Yellow Pages for "Air Conditioning Contractors"
    Last edited by Dobbs; 05-21-2014 at 03:24 PM.

  3. #3
    Join Date
    Apr 2014
    Posts
    51

    Default Re: A/C - Ductless system vs portable unit

    It's about 800-900 sq feet. One big open area with 3 bedrooms. Trying to cool the main area which is @ 500 sq feet with cathedral ceiling.

  4. #4
    Join Date
    Feb 2008
    Posts
    206

    Default Re: A/C - Ductless system vs portable unit

    Celia,

    I got a rough estimate for 500 sq.ft. of 17,160 btu/hour required for the main area from the sizing at ac site: http://www.csgnetwork.com/acroomsizecalc.html

    I assumed that you have some sun esposure, the ac won't be placed in the kitchen, & you have average insulation; since you have a cathedral ceiling, this may bring the equipment need up to approx 20,000 btu/hr.

    If you calculate for the 800-900 sq.ft. to cool, you would need an ac unit of approx 25,740 btu/hour---you would need at least a 20 amp dedicated time delay fuse at your main electric panel to accomodate this size AC.

    Please click onto csg network & do the calc yourself to modify sun exposure, kitchen exposure, amount of insulation.

    Another issue with the mini-split style of AC with the compressor unit sitting outside the cottage, & the cottage is vacant during the winter is the threat of theft or vandalism of the compressor during the winter months.
    Last edited by Dobbs; 05-21-2014 at 03:55 PM.

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