How much does it cost to install air conditioning?

[David M]

Originally Posted by djtopper

I can imagine it being quite difficult to cool off what is basically a floating condominium with little or no shade in warm climates. The sun is indifferent to what it's heating up and it has a LOT of power.

I've wondered why there aren't any systems that use the water itself to help the process. I mean, water will generally be less than 80 degrees. In theory that should help you cool 100 degree air at least a little bit. It's the same idea as geothermal heating/cooling systems for houses.

Anyone want to try? I'm happy to lend ideas and elbow grease. ;-)

That small of a temperature difference would require a massive heat exchanger for the air and boats just don't have the room. Coolant going from a liquid phase to a gas phase change does provide the temperature difference necessary to not require a massive heat exchanger. The other problem is the air could never get cooler than the temperature of the water.

Boats can and do use raw water to cool the coolant which gets very hot after being compressed back into its liquid phase. Water absorbs much more heat than air allowing for a more compact heat exchanger than if the heat is released into the air like what a home refrigerator does.

[Group9]

Originally Posted by jeremiason

Our thre Marine Air units have worked well for the last 6.5 years as both heaters in San Francisco and for AC in the tropics.

In the high humidity areas they suck out about 5 to 7 gallons of water from the cabins per hour, which drains to the bidlge. Ours were factory installed, which charges much more than if you installed them yourself.

Depending on the size of the unit, you should be able to install two units on your boat for less than $4k, if you do it yourself...

You can normally run two AC units on one raw water pump, but remember you need an in and out thru hull. So you might have to do a qiuck haul out to install the intake, unless you have a unused thru hull already. The raw water outlet would be above the water line and normally does not have a valve.

As far as window unit... Several of my buddy boats, in an attempt to save money use window air conditioners on their fore hatches or companion way. These work ok, but you have to store them underway and get them out when stopped. Then you have to work around them when they are in place... They also rust pretty fast. For me that sound like too much work.

The one good thing about a window unit over a water cooled unit, is that it always made me nervous to leave my Marine Air running when I left the boat for a few days. The idea of one of the hoses blowing or coming off and flooding the boat made it too risky.

With the window unit, it keeps the humidity down, and you don't have to worry about the boat sinking.

[Tim R.]

A window unit would never work for us. We use our boat two much to deal with moving a unit in and out of the boat every time we want to go sailing. We only ever leave our boat with the AC running for a few hours at a time when at work. Our dog would roast without it. I also am fairly anal when it comes to maintenance and below WL connections. Our redundant bilge pumps and high decibel alarm would get the attention of not only the marina staff and other boaters but most all patrons in the marina restaurant.

Our AC is also reverse cycle so it does get used at the dock in the fall. We have a diesel furnace for heat at anchor and during the colder months.

[Suijin]

I'm going to second that including AC in your boat search criteria is not a good idea given how easily and inexpensively most boats can be retrofit with it.

It's a bit like confining your search for a used car to only those vehicles that have a specific brand and model of tires.

[mark_morwood]

Don't forget that you'll need a generator if you want to use these air conditioners when you leave the dock.

Mark.

[djtopper]

Thanks for all the replies. They've been helpful, educational, and interesting.

So it seems as though if I eliminate AC from my search criteria I need to be prepared to upgrade the generator and install the AC hardware myself.

My remaining question then is about the ductwork. Is that hard to install? Or are most boats designed with the necessary ducts in mind, leaving the installation of which to some precise cutting? I'd hate to make decisions on where to install ducts myself and end up slicing through something by accident.

[motion30]

My 44' my. Has 2.16000 btu units. 1 handles the salon the other handles the forward and the rear births. I do have 2 30 amp 110 circuits 1 30 amp circuit handles all the house loads the other 30 amp circuit handles both air conditioners my 8k genset handles everything no.problem. my boat has lots of glass in the salon in the South Florida summers window coverings really help

[GrowleyMonster]

My little boat cools okay with just a 5kbtu window unit. I built a cowl for it over the forehatch. Vers.1 cowl was big and bulky and very heavy. V2 is about 10 lbs, mostly 1/4" plywood and a few bits of 3/4" pine. One layer of mat over the top, a couple layers of cheap polyester resin on top of that. Now it takes all of a minute to break it all down to go sailing. I don't need AC when I am sailing, and at anchor I have a 12v fan. Anyway my window unit was I think around $100 at walmart. Plywood was $9 and I only used half of the sheet, and the pine was a couple more bucks. Resin from Home Depot. A gallon is $26. Mat was from a big roll I bought a year ago for $56 so about 50 cents worth of mat, maybe. Oh, about $5 worth of #6 3/4" screws. So all in maybe $150 for cooling, and I can figure on replacing the year-old AC unit in another year or two. I'm kinda okay with that. I would post a pic but the weather is miserable outside this morning so I am relaxing at the puter while the wind blows and the rain rains.

[zeehag]

tim r--i use the wondow unit only because in summer, here in furycameville, folks dont go cruising or do much sailing out in the ocean. we go into nice marinas with low prices as it is off season, and keep to a minimum of activity. we might effect repairs, but we dont temp momma nature with evile weather by actually sailing in summer.
sitting in 110+ weather for a few months isnt gonna be done without an air conditioner, and a window unit is just the ticket for us her in our pair a dice--we use tarps for sun control and we use a/c for humidity and some heat control. works great and window units are not heavy. they are easily stowed in a 41 ft boat, and easily installed when the boat has windows for its use, as does mine.
if i had perfect weather year round, i would never have to have even bought the unit. but it isnt in use when i am anchored or under sail, so isnt installed until a marina comes into use. or a haul yard.
as for appearances--i truly do not give a rats behind what my boat and its appearance group represent--it is a work in progress--dont like it--judge not lest thee be judged....LOL

[Ita]

Hey Growleymonster, I did the same but I use a plastic storage bin ($10) with a cut on une side as cowl, cover in the inside with a towel.
Perhaps one day I'll cover it with silver isolation......

[GrowleyMonster]

Originally Posted by Ita

Hey Growleymonster, I did the same but I use a plastic storage bin ($10) with a cut on une side as cowl, cover in the inside with a towel.
Perhaps one day I'll cover it with silver isolation......

Nice.

[letsgetsailing3]

Originally Posted by Ita

Hey Growleymonster, I did the same but I use a plastic storage bin ($10) with a cut on une side as cowl, cover in the inside with a towel.
Perhaps one day I'll cover it with silver isolation......

Good answer.

[Group9]

Originally Posted by Ita

Hey Growleymonster, I did the same but I use a plastic storage bin ($10) with a cut on une side as cowl, cover in the inside with a towel.
Perhaps one day I'll cover it with silver isolation......

Exactly what I did, with some weather sealing tape/foam from Home Depot.

[Rakuflames]

Originally Posted by David M

Sorry, I respectfully disagree with purchasing a home air conditioner and sticking it through the window of a boat for a number of reasons.

LOL! The boat next to me has a window AC in the hatch. He has emphysema and needs it. He built a companionway enclosure that supports it well. Not sure what he does with it when he sails -- he's just moved in.

[GrowleyMonster]

Originally Posted by Rakuflames

LOL! The boat next to me has a window AC in the hatch. He has emphysema and needs it. He built a companionway enclosure that supports it well. Not sure what he does with it when he sails -- he's just moved in.

I tried that, but it was a big PITA cause it was a LONG stretch to step over it to go below. But others have been quite satisfied with a companionway mounting, and you don't have to break it down to go for a little sail like you do with a forehatch mount.