Sticker shock: air conditioner

[Dave22q]

Marine units cost more for good reason. They are designed for the environment. You can jury rig a room A/C unit for a few hundred but expect an ugly look and a short service life. However, the prices quoted for marine built in units are absurd. I find starting shopping at West Marine to be an easy way to get a fix on prices although biased high.
A quick look indicates multiple choices for 16000 BTU at 2k with maybe another 1k for parts and labor to install.

[tdoster]

The portable units will NOT have the same BTU comparison. In simple terms you have two sides to a a/c unit and lets just call one side cold and the other hot for absolute simplicity. To get cool air on the cold side, you have to dump and cool the hot side. The differences between window, portable, and marine are as follows:

Window hot side is on the outside. Uses fresh air to dump the heat.

Marine heat is dumped to the seawater being pumped through.

Portable uses inside air, then dumps that to the outside using then vent hose. This means that for all of the air being dumped through the exhaust vent, it has to be replaced by air from the outside, which lowers the overall BTU of the a/c. Term spot cooler is used because it does fine cooling one area, but another area where air is pulled leaking from the outside is hot.

16K is high, but if you have a 12k btu installed by a professional, it would probably run you between 3 and 6k depending on the runs for vents, pump, and through hull. So, figure it should be 10K max.

Then again, who pays sticker on a new boat?

Least expensive and efficient is window unit in the companion way, but the you have a storage problem. Commercial fishing boats usually use units similar to rv roof units, and by far the most efficient, but an ugly roof unit looks good on a fishing trawler, but not so much on a yacht.

[smj]

The best ac for cooling the boat that we have had was a Coleman rv rooftop model. It would cool our 38' catamaran down into the 60's on a humid 90 degree Texas summer afternoon. It was a little large on the deck, but they do make low profile models and even a marine unit now.
The second best was a window unit. Inexpensive, cooled well but did give it the ghetto ambiance. Who cares if your inside and comfortable.
Seemed to me the water cooled marine units were the most inefficient. In most places when it's hot outside the water is also hot. I'm sure they would be more efficient if your located in an area where the water is cooler. A couple of other things I didn't like about the marine units are it seemed the filter would always clog sometime between midnight and 6:00 am and I never felt comfortable running it when we were of the boat as I had a couple of friends that had the hose rupture and almost sank the boat. They do look nice and remain concealed though.

[Cormorant]

I was curious about this part of the the DeLonghi description:

"No Drip Technology
Exclusive condensate recirculation system with NO DRIP TECHNOLOGY makes the air conditioner more efficient and more user friendly (never empty a bucket again). The washable filter is also easy to access."

So . . . where does all that condensate go? It recirculates? Do they somehow send it out with the hot exhaust?

[john61ct]

Just doesn't remove much vapour from the air?

[Cormorant]

"--Dehumidifies while conditioning (removes 54,95 pints/24h of excess moisture)
--Dehumidifying only function (removes 86,65 pints/24h of excess moisture)"


So that's 6-10 gallons a day it has to get rid of. Just curious how it works.

[DotDun]

Originally Posted by smj

The best ac for cooling the boat that we have had was a Coleman rv rooftop model. It would cool our 38' catamaran down into the 60's on a humid 90 degree Texas summer afternoon. It was a little large on the deck, but they do make low profile models and even a marine unit now.
The second best was a window unit. Inexpensive, cooled well but did give it the ghetto ambiance. Who cares if your inside and comfortable.
Seemed to me the water cooled marine units were the most inefficient. In most places when it's hot outside the water is also hot. I'm sure they would be more efficient if your located in an area where the water is cooler. A couple of other things I didn't like about the marine units are it seemed the filter would always clog sometime between midnight and 6:00 am and I never felt comfortable running it when we were of the boat as I had a couple of friends that had the hose rupture and almost sank the boat. They do look nice and remain concealed though.

Water cooled is the most efficient. The water is usually cooler than the air, plus water is a much more efficient medium at heat transfer.

[john61ct]

Originally Posted by Cormorant

"--Dehumidifies while conditioning (removes 54,95 pints/24h of excess moisture)
--Dehumidifying only function (removes 86,65 pints/24h of excess moisture)"


So that's 6-10 gallons a day it has to get rid of. Just curious how it works.

sorry to its fans, but I'm skeptical of any of their claims

[DotDun]

Originally Posted by john61ct

sorry to its fans, but I'm skeptical of any of their claims

They run the condenser hot air over the water and it goes out with the exhaust.

[smj]

Originally Posted by DotDun

Water cooled is the most efficient. The water is usually coolerk than the air, plus water is a much more efficient medium at heat transfer.

Not my experience. We have had much better luck with the air cooled Ac's.

[DotDun]

Originally Posted by smj

Not my experience. We have had much better luck with the air cooled Ac's.

Then your water cooled unit(s) were either not installed properly or not maintained properly, or both.

[smj]

Originally Posted by DotDun

Then your water cooled unit(s) were either not installed properly or not maintained properly, or both.

All installed and maintained correctly. We finally got to the point where we would remove the marine ac on any boat we purchased. We don't use the ac while at anchor, only when we were living aboard at a marina full time, and for those times we found the rv or window unit produced more cold air and was much cheaper. Also as I said, no chance of failed through hull, seacock or ruptured hoses with the air cooled. Also no problems with cleaning filters or replacing water pumps. We did give up the convenience though.

[sck5]

This thread is cracking me up. All of those thousands of boats with marine AC units have owners who are so rich they don't care about how much the AC costs. Also, none of them have ever heard of the concept of a "window air conditioner" so they just shelled out the thousands of dollars for marine units without even thinking of alternatives.

Now that this thread exists we will rarely see marine AC units on new boats. Now that the scales have dropped off of their eyes, all of those owners will trot on down to Best Buy and get window units which they can easily use with no problems.

[smj]

Originally Posted by sck5

This thread is cracking me up. All of those thousands of boats with marine AC units have owners who are so rich they don't care about how much the AC costs. Also, none of them have ever heard of the concept of a "window air conditioner" so they just shelled out the thousands of dollars for marine units without even thinking of alternatives.

Now that this thread exists we will rarely see marine AC units on new boats. Now that the scales have dropped off of their eyes, all of those owners will trot on down to Best Buy and get window units which they can easily use with no problems.

The water cooled ac's may be very efficient where the water is cool, but in the summer time where we are located the water temp is over 90 degrees so doesn't seem to be as efficient.
The water cooled marine ac's are also more convenient and hidden and controlled like a central home unit, so more popular.
For us the air cooled does a better job where we are located and since we don't need an ac while cruising and we have a weight sensitive catamaran and can easily remove the air cooled unit it's the best for our application.
Don't worry, the marine units won't go out of business.

[DotDun]

Originally Posted by smj

All installed and maintained correctly. We finally got to the point where we would remove the marine ac on any boat we purchased. We don't use the ac while at anchor, only when we were living aboard at a marina full time, and for those times we found the rv or window unit produced more cold air and was much cheaper. Also as I said, no chance of failed through hull, seacock or ruptured hoses with the air cooled. Also no problems with cleaning filters or replacing water pumps. We did give up the convenience though.

No argument that water cooled systems require more maintenance. My point is that water is more efficient at cooling the AC condenser than air. You stated that water cooled systems don't work when the water is warm and that's a trait of poor installation and/or poor maintenance as in a proper system 90° water will cool the condenser as well if not better that 90° air. It sounds like the you are arguing the reliability of each system, and I will state reliability is a maintenance or manufacturer symptom, not an efficiency attribute.

I just replaced (1) of my 16kBTU units that was 13+ years old. It died as the compressor rotor locked up. The condenser cooling system was still working fine.