Air conditioning

kito · Jul 3, 2014

I have a Newair 10k btu unit on my H30. Only thing about these kind of units is that it draws cooled inside air and exhausts it out (hot air). This means the exhausted air needs to be replaced and draws outside hot air through all the little cracks and mixes with the inside cooled air....not very efficient. They make the 2 hose units that may work better...one for exhaust and one for outside air intake. Mine is a 1 hose unit but I have rigged it to work more like a 2 hose unit. Mine is in an enclosed hanging locker with the exhaust hose going out a portlight. I also installed another hose from the locker to a portlight so it draws most of it's air from the outside instead of using cooled inside air. Seems to work great. Last night when I turned it on and cooled it from around 97 to 85 in about a half hour. Not bad, plus just knocking down the humidity makes a big difference. I also wrapped the exhaust hose with insulation. That hose really radiates a lot of heat.
Btw, I can run my unit off a portable 2000 watt generator. Not sure that would be possible with a window unit.

Winkfish · Jul 3, 2014

As I recall when I used to have window units, they drew from and blew into the inside, recirculating the already cooled air. Less work. They neither pulled from the outside nor vented to the outside. The only thing that vented to the outside was a hose that got rid of condensation to outside. are these different types of units?

kito · Jul 3, 2014

Winkfish said:
As I recall when I used to have window units, they drew from and blew into the inside, recirculating the already cooled air. Less work. They neither pulled from the outside nor vented to the outside. The only thing that vented to the outside was a hose that got rid of condensation to outside. are these different types of units?

Yes, think of it like a clothes dryer. The dryer exhuasts it's hot air outside. It draws from room air.
Window units are more efficient since no outside air is drawn in or out.

rufus1138 · Jul 3, 2014

ive had great luck using window units mounted in the comanion way, my current unit is a 12k btu unit i believe, not sure really it came with the boat and is a very nice lg model with a great economy brain that cycles and senses air temp and keeps from running so much and has a soft start that keeps it from spiking the circuit.

Skipper · Jul 3, 2014

There was a recent thread that evolved into a window vs inside portable unit topic:

http://forums.catalina.sailboatowners.com/showthread.php?p=1122685

kito · Jul 3, 2014

I guess it depends on what you need. The pros of a window unit in the companion way is better cooling per btu compared to a portable unit. Cons is having to set it up....climbing over it to get to the cockpit and not being able to use it off a portable generator. If you don't have room for a portable unit then where are you going to store the window unit? My portable unit is about 15" square and 28" tall. I attached a pic of my setup (boat is being restored). If you can find a place to permanently mount your portable unit like me, it's a great option over central units. All I have to do is run the hoses out the port on top and close up the locker opening with my bedroom door. I don't need to freeze.....just want it to be comfortable. If I slide the solon door shut I makes the smaller area quite cool. I love the idea of anchoring overnight and being able to get cool off my generator. Probably the biggest reason I went this route.

Ken13559 · Jul 3, 2014

Kito, that's a great idea getting a portable A/C with in/out air duct. One more great idea to go into my book. Thanks! :dance:

mrducks · Jul 4, 2014

My friend sent this link yesterday. Not what you are talking about but still a great idea for a small cabin like my Cat 22 on a hot day sail. A simple cheap way to make the temp tolerable.
http://www.youtube.com/watch?v=HxSLbpAwibg&sns=em

Benny17441 · Jul 4, 2014

No they are not better than a hatch mounted 5K unit and I would not recommend it. The units use cabin air to cool the compressor and then exhaust it out of a 4 1/2 inch hose. The hose radiates heat inside the cabin fighting the cooling effect of the unit. There is also the volume of air being exhausted by through the hose. This air which was already cooled is being replaced by hot humid air from the outside which will filter in any small openings. This makes the units not to efficient and where a hatch 5K unit might suffice you will likely need a 10K portable. My experience is that they work good in home use but leave a lot to be desired when used in a boat. That hatch mounted unit cools it compressor with outside air and there is no exchange of air between the outside and inside.

kito · Jul 4, 2014

Benny17441 said:
No they are not better than a hatch mounted 5K unit and I would not recommend it. The units use cabin air to cool the compressor and then exhaust it out of a 4 1/2 inch hose. The hose radiates heat inside the cabin fighting the cooling effect of the unit. There is also the volume of air being exhausted by through the hose. This air which was already cooled is being replaced by hot humid air from the outside which will filter in any small openings. This makes the units not to efficient and where a hatch 5K unit might suffice you will likely need a 10K portable. My experience is that they work good in home use but leave a lot to be desired when used in a boat. That hatch mounted unit cools it compressor with outside air and there is no exchange of air between the outside and inside.

Yes....did you not read my post above? They work fine if installed properly. Mine cools just fine....and off a small generator too. They are not for everyone but my H30 is setup great for these units. YMMV

Picflight · Jul 4, 2014

Great idea Kito!

capta · Jul 6, 2014

I have a friend who bought one of these for his boat, for the summer in the Charleston City Marina. It seemed to function quite well, and he left it on low cool and went off to work. Best the fire inspectors could tell is that it used just enough power to heat up the line to the outlet, which eventually caused the fire that destroyed his boat. Perhaps the marina power dropped a few volts as the afternoon heated up and others turned on their a/c's as well; we'll never know. End result; guy lost his boat and everything he owned.
Beware of high amp house hold appliances aboard a small boat.

kito · Jul 6, 2014

capta said:
I have a friend who bought one of these for his boat, for the summer in the Charleston City Marina. It seemed to function quite well, and he left it on low cool and went off to work. Best the fire inspectors could tell is that it used just enough power to heat up the line to the outlet, which eventually caused the fire that destroyed his boat. Perhaps the marina power dropped a few volts as the afternoon heated up and others turned on their a/c's as well; we'll never know. End result; guy lost his boat and everything he owned.
Beware of high amp house hold appliances aboard a small boat.

My unit draws 7 amps. I ran 12 gage tinned stranded wire to my ac outlet which is a dedicated circuit. Not sure what your friends wire was. Good point though......check your wiring and breakers before plugging in any 110v appliances.

garyg · Jul 7, 2014

I installed a 5000 btu window unit in the forepeak bulkhead of my 1970 Morgan 33 in 2009. It exhausts into the forepeak anchor chain area and then out through a deck cowl vent and the anchor chain pipe. These openings are equal in size to the hose of a portable room A/C unit. My installation was a feature article in DIY Boat Owner issue #3 2009 ( the publication is out of print). I have photos for interested parties.

wflowe2 · Jul 7, 2014

I've used both a window unit mounted in the companionway and the free standing one mounted on wheels. The free standing unit had so much heat from the exhaust hose that it off set the cooling. It also took up a lot of space.
The window unit worked great. I just made replacement hatchboards with a cut out for the AC.
These wer both used on a Beneteau Oceanis 281

twdevore · Jul 7, 2014

I'm using a 10K portable until our permanent A/C is hooked up and it works really well. Read above as it does pull air in through any opening and the hose does need some insulation wrapped around. Stowing it can be a problem. I just have it lashed to the mast. Weighing the options of the hatch mounted, only 5 or 7 BTU and the cost of it, versus getting the 10K second hand on Craigslist ($200) is what sold me. I wouldn't want to take the hatch unit off every time I went out. If I recall, they stopped making the hatch units. I may be wrong. The water created is supposed to drip on the condenser and be exhausted on my portable but it still needs drained occasionally. I like Kito's setup!

Pat · Jul 7, 2014

Before installing a Mermaid, we had an 8600 btu suitcase ac that had two hoses...one for lake water in, one for discharge...although a bit noisy, I could set the unit in our 272 quarter berth (I replaced the Quarterberth upholstery with dark green vinyl to match the rest of the cabin in color) the unit really cooled the cabin on very hot Kansas summer days....Better than the 12,000 btu Mermaid....but the garden hose connections were a pain to deal with (quick-connect) as they leaked slightly...I ran them in and out the opening hatch into the quarterberth from the cockpit...this obviously was for use only in the slip...although I suppose one could use a generator at anchor or on a mooring.....they are much handier than a window AC unit in a companion way...I had no trouble selling it when we installed the Mermaid....took maybe 30 minutes....it worked well. Pat

Ericb760 · Jul 7, 2014

Long time lurker, first time poster.

This is my DIY AC that I made for my Yankee Dolphin 24. Cost less than $20 dollars, not including two blocks of ice. It worked good, not great, but good. It cooled the boat from 92 degrees at 9:00 PM, to around 82 degrees in the early morning hours. Two main drawbacks were, 1. It's noisy, and 2. It did add quite a bit of humidity to the boat.

All in all, it's fine for the occasional overnight, but not practical, or cool enough, for anything long term.

The video:

https://www.youtube.com/watch?v=M69oDNdtmRo

Air conditioning

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