AC Sizing

  • July 17, 2013 6:37 AM
    Message # 1342519
    Hi All-

    I am getting ready to put an AC unit in my W32 and am looking for advice on sizing and recommendations for brands.  I am not interested in the hatch models-  have tried that route, and am looking for a permanent installation.  I will be doing the work myself.  The various sizing tools that I have used indicate around 9-11000, but it seems like folks have been a bit higher that that for the installations I have seen.  The boat stays on a dock in Beaufort, NC, year round.  The ability to run off a generator like a Honda Eu2000 would be a plus, but not a deal breaker-  Thanks.

  • July 17, 2013 2:27 PM
    Reply # 1342912 on 1342519
    Contact Butch Rasmussen in Deale, MD.  He lives aboard his W32 Legend, and sells and installs air conditioning and refrigeration units, and will give you the straight info on what it takes to do a proper job.  or 401-867-6023
  • July 18, 2013 6:25 PM
    Reply # 1343807 on 1342519

    I have a King-Air 16,500 BTU 'reverse cycle' A/C (heat/cool & humidity control) installed in my W32. I really don't think I'd want one with less BTU's, at least here in the tropics where the 'feel like' temp & humidity can commonly be 110 F by 10AM.  Obviously your requirements will vary depending on your location, insulation, etc..  As expensive as they are I would NOT want to save a few bucks by underestimating BTU's however (can you really overestimate?)

    I've had it running 7X24 here in the tropics for going on 9 years.  I know I have have severely mistreated it yet it keeps on going where other A/C's around me (brands unknown, but the more commonly known) have bit the dust.  I attribute it's longevity to the upgraded digital control that will shut it down if certain conditions are met (overheating due to clogged filter, low freon, under voltage, etc.). 

    That said, I did just replace the control board recently when I moved to a new marina where (unknown to me until too late) the power quality is atrocious and surges are common.  More my fault for 'assuming' than the A/C's.

    The compressor, electronics, etc. is mounted on top of the lockers opposite the head. I have a duct going into the V-berth and one into the main cabin.  The digital control is located on the main bulkhead in the main cabin. The upside is it makes for a very simple, compact installation. The downside being you lose the space for your spare change & car keys :)

    It's very energy efficient, adjusting fan speed to temp, shutting water pump off when compressor isn't running, etc..  Still, 'under load' it draws about 14 amps making it out of the range of a single Honda EU2000 (although a daisy chained pair would work).  I pay about .50/Kw and my power bill averages about $125'ish a month keeping the boat at a steady 81 deg (I do have an awning that shades the deck so that helps too).

    I'm sure others have their preferences, installation ideas and suggestions.  For me at least if I had to install an A/C in another boat (or replace this one) it would absolutely be another King-Air.  I certainly recommend checking it out.


    Last modified: July 21, 2013 1:03 PM | Anonymous member (Administrator)
  • July 18, 2013 9:49 PM
    Reply # 1343886 on 1342519
    Deleted user
    I have a Sea-Breeze 16,500BTU unit and am more or less satisfied with it.  The unit itself runs well but I've had some issues with the digital temprature control.  As far as size if I were installing it again I'd try to go larger possibly up to 20,000BTU.  Here in south Texas on 100F days it struggles to hold its own, when it drops into the 90's it will take the cabin down into the lower 80's, at night its fine, goes down to the 70's. The installation is under the V berth and is a bit noisy but you get used to it.  If possible insulate everything.  Odd note in that I have a awful problem with jellyfish clogging the strainer and have yet to come up with a solution that works.  If anyone has any ideas I'd appreciate it, its no fun trying to backflush the unit at 2am.
  • July 19, 2013 9:31 AM
    Reply # 1347314 on 1342519
    Deleted user
    Still haven't figured out how to insert an image with the Mac.

    This has worked well for 1 1/2 summers in Central Florida.

    Daytime with awning up holds the cabin about 10 to 15 degrees below ambient temperature.

    Nighttime, sleeping in the v-berth, grab a blanket.

    My electric bill in summer is about 35.00 compared to 175.00 for my neighbor who has marine air on his Columbia 39.

    Runs on the Honda EU 2000 at eco throttle. (All night) with fuel left over.

    This was a "temporary" installation while I decided which marine unit to install. It's not temporary anymore.

    5000 BTU LG Unit at Home Depot on sale at 89.95
    Fittings and hose for condensation drain about 7.00
    Two bathroom vent fans scrounged from a remodeling job on a condo  Free
    1 AC Light Switch and Plate 3.00
    PVC for "Plenum Chamber" bulkhead Free (on hand)
    1 Extension Cord 5.00
    6" hole saw rental 6.00
    Mistakes about 15.00

    Cost about 125.00 to install

    Budget Air Conditioning
    Last modified: July 21, 2013 1:02 PM | Anonymous member (Administrator)
  • July 21, 2013 8:06 AM
    Reply # 1348203 on 1342519
    I have a 12000 btu ac on jasmine and it works fine in florida.  The awning helps alot though I am sure, but as long as the boat is closed up, it keeps it cool.  Takes a 1/2 hour or so to get there if it is hot below but keeps it there fine.

    And I have a black hull.

    Hope this helps.

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