Portable AC ?

[PhilPB]

Looking for opinions.
In lieu of replacing current ac that doesn't cool our entire cabin well but still works ok (this is in a 95°f Florida environment).
Debating the possibility of adding 12k-14k btu portable unit.
The cost for the unit is approximately 25% of a normal uninstalled marine ac unit. If I were to pay for marine unit as well as paying for install the cost drops to about 10%.

 

[O C Diver]

Looking for opinions.
In lieu of replacing current ac that doesn't cool our entire cabin well but still works ok (this is in a 95°f Florida environment).
Debating the possibility of adding 12k-14k btu portable unit.
The cost for the unit is approximately 25% of a normal uninstalled marine ac unit. If I were to pay for marine unit as well as paying for install the cost drops to about 10%.

Before doing that, have you checked your current system to see if it's performing to rated capacity?

Things that can reduce rated capacity are:

Raw water flow. With the unit running, catch the discharge water with a 5 gallon bucket. Depending on the size of the unit, you probably want 5 GPM or more of cooling water going through the condenser. Reduced flow can be from several reasons, but optimal flow is important when water temperatures are in the 90s.

Make sure the condenser tube is clean. Marine growth on the inside of the condenser tube becomes an insulator.

Make sure the evaporator coils (and air filter if equipped) are clean. Dirt becomes an insulator when doing heat transfer.

Make sure the supply and return ducts are unobstructed.

Finally, get an AC digital thermometer to measure the differential between return and supply duct temperatures. If your measuring minimal difference, that may indicate a problem like an icing evaporator coil.

Ted

 

[Larry M]

We've used a couple portable units through the years with marginal success. While on the hard, we adapted a window unit over the forward hatch. It was good for sleeping but that was it. We also used a free standing AC unit. Very noisy, it took up a lot of space and we had to adapt a side window to dump the hot air.

At the end of the day, built in AC units were the best.

 

[Dwk]

I started looking at where to put a portable ac unit after reading this thread if I was adding one that wouldn’t be in the way. How about the aft starboard corner directly in front of the fixed glass panel next to the sliding door? Venting outside could be done thru the aft bulkhead or out the window with modifications. Mind you,I do not have exact dimensions,just going off my recall of portable upright units requiring a 4-6 inch vent
Btw our 16 btu ac cools our Mainship adequately in the hot humid Maryland weather with fans moving the air. Good luck! David

 

[Comodave]

First try to keep the heat out of the boat. Cover the windows. That can make a big difference. We have used Pfifertex and Stamoid for exterior covers. Covers on the outside work better than on the inside.

 

[OldDan1943]

What size, brand and age is your unit?
They do make booster fans that fit in the A/C duct work.
One of my A/C came with a box to split the air between the saloon and fwd S/R. I replaced the box with an adjustable Y splitter. Greatly improved the A/C in the fwd S/R

Are you considering a window unit or a ‘split unit’?

 

[PhilPB]

I started looking at where to put a portable ac unit after reading this thread if I was adding one that wouldn’t be in the way. How about the aft starboard corner directly in front of the fixed glass panel next to the sliding door? Venting outside could be done thru the aft bulkhead or out the window with modifications. Mind you,I do not have exact dimensions,just going off my recall of portable upright units requiring a 4-6 inch vent
Btw our 16 btu ac cools our Mainship adequately in the hot humid Maryland weather with fans moving the air. Good luck! David

That is exactly where I figured it would go except on the port side. Already have outlet in that location as well. Our unit cools, just not as well as I would like.

 

[PhilPB]

What size, brand and age is your unit?
They do make booster fans that fit in the A/C duct work.
One of my A/C came with a box to split the air between the saloon and fwd S/R. I replaced the box with an adjustable Y splitter. Greatly improved the A/C in the fwd S/R

Are you considering a window unit or a ‘split unit’?

It is an Aqua-Temp. No idea of age and have received different answers as to size. I have had answers of either 12k btu & 16k btu. The panel looks original. I was thinking of a stand alone 12k-14k btu unit with an exhaust hose.

 

[PhilPB]

First try to keep the heat out of the boat. Cover the windows. That can make a big difference. We have used Pfifertex and Stamoid for exterior covers. Covers on the outside work better than on the inside.

We have inside blackout drapes and windshield has outside cover as well as reflective/removable shade on inside. When I redid the cabin with teak plywood I also insulated the sides with layers of foil/bubble type insulation from Home Depot. Maybe an r3 rating. It's a lot of windows, 80's Era build

 

[PhilPB]

Before doing that, have you checked your current system to see if it's performing to rated capacity?

Things that can reduce rated capacity are:

Raw water flow. With the unit running, catch the discharge water with a 5 gallon bucket. Depending on the size of the unit, you probably want 5 GPM or more of cooling water going through the condenser. Reduced flow can be from several reasons, but optimal flow is important when water temperatures are in the 90s.

Make sure the condenser tube is clean. Marine growth on the inside of the condenser tube becomes an insulator.

Make sure the evaporator coils (and air filter if equipped) are clean. Dirt becomes an insulator when doing heat transfer.

Make sure the supply and return ducts are unobstructed.

Finally, get an AC digital thermometer to measure the differential between return and supply duct temperatures. If your measuring minimal difference, that may indicate a problem like an icing evaporator coil.

Ted

Used 2 gallons of Barnacle Busters and it went from blue to black. Pumped for couple hours.
Coil was shockingly free of dust and dirt. I even used ny coil comb/brush and removed nothing.
Ducts are unobstructed.
Waiting for delivery of infrared thermometer.
Will check water flow rate next

 

[Larry M]

…I was thinking of a stand alone 12k-14k btu unit with an exhaust hose.

A 14k BTU stand alone may not be big enough to cool the area you want unless that is the DOE rating which few manufacturers list prominently in their marketing or sales specs. Below is a 14k BTU Westinghouse unit. The DOE rating is 8k BTUs. The 14k rating is how many BTUs the unit can remove from the air but it doesn’t take into account that the compressor adds heat to the room. With a window ac unit, all the heat generating components are outside the area you’re trying to cool. I’m not sure but I don’t think there are different ratings for window units. The DOE ratings came about maybe 5 years ago.

Another consideration of stand alone units what do they do with the condensate? Some have a hose drain, others have a pan that once it’s full, the unit will shut off and some dump the moisture through the exhaust hose.

Stay cool.

 

[PhilPB]

The plan isn't to replace the current unit, just a unit to supplement the lack of cooling. Currently it takes a couple of hours to get the cabin cool-ish and maybe 3 hrs to go from baking hot to cool.

 

[O C Diver]

The plan isn't to replace the current unit just a unit to supplement the lack of cooling. Currently it takes a couple of hours to get the cabin cool-ish and maybe 3 hrs to go from baking hot to cool.

Those numbers aren't really that bad. Boats generally lack insulation and more importantly it takes a long time to remove the heat within the walls, floors, ceiling, cabinetry, and everything else within the boat. While it's easy to remove maybe 5 to 10 degrees and a lot of humidity, below that point, all the objects and the boat itself start dumping their heat into the air. In an ideal world, boat air conditioning should be able to maintain the the set point on the hottest day with an 80 to 90% compressor duty cycle.

If you want the rapid performance of car air conditioning, you probably need 60,000 BTUs of cooling capacity. Your car for its smaller size, probably has 8,000 to 12,000 BTUs of AC.

Ted

 

[alormaria]

If you insist on using a portable go for one with two (2) hoses; one intake and one exhaust. Whynter makes one. The single hose ones pull their cooling air from inside the room and that sucks hot air in from the outside. You'll be air conditioning the marina.

 

[PhilPB]

If you insist on using a portable go for one with two (2) hoses; one intake and one exhaust. Whynter makes one. The single hose ones pull their cooling air from inside the room and that sucks hot air in from the outside. You'll be air conditioning the marina.

That's very useful. I didn't know that. That sways me more against the idea of a portable unit.

 

[alormaria]

That's very useful. I didn't know that. That sways me more against the idea of a portable unit.

I speak from experience.


I tried a Haier single hose 12K unit on my boat. Useless.

It did remove humidity but never did drop a single unit of temp after running all day. It was 90 degrees. But eventually it was a dry heat.



Works well at home as a backup for window units. Works very well in conjunction with a window unit in another room. Everything about a portable works better at home. Even so the dual hose models still excell.



FYI just today I finished installing a Wabasto 16K marine unit on the boat. Installation was a real trial but I took my time and enjoyed the challenge. Expensive. Even doing it yourself. But it pulled the temp from 88 degrees to 73 in no time. Quiet.

Glad that's over.

 

[BruceK]

We had one at home. Noise was the main negative, it`s a compressor in your room, even a "window rattler" doesn`t do that. It did cool, lacked the performance of a split system which replaced it. Still have it in my study but rarely used, check the rated noise output and try to verify it`s for real.

 

[Lepke]

I avoid hot weather, but when I get caught, I have 2 of the portable roll around units. They seem to work ok in 80°+ weather.
If you buy one, make sure it uses 2 hoses. One brings outside air for the condenser and the other exhausts the heated air. The single hose unit has to use already cooled inside air that causes outside air to be drawn into your boat.

 

[psneeld]

I had a small 8000 btu (IIRC) unit for years. I placed it behind the lower helm and put the exhaust out through a hole in a 1X8 that I cut to fit in the helm side sliding door with a little weather stripping to keep it all rainproof.

I used it when away from the boat to keep it cool and lower humidity when going away from the boat for long enough I shut the doors, windows, and hatches and locked her up.

Also used it when it was hot and still in the late mornings in New Jersey where the sun warmed the boat a bit too much and the sea breeze hadn't started yet. It wouldn't cool the whole boat on hot days, but was perfect for the need I used it for.

The boat was older and I didn't trust the old A/Cs to run while not aboard. I eventually replaced the A/Cs and plumbing...but for those years till that project bubbled to the surface.... the couple hundred dollar free standing A/C did the trick.

Not a great solution, just the best at the time.

 

[boomerang]

I just noticed yesterday, while perusing boats for sale, a Mainship with the setup you're talking about. The unit is in the starboard corner of the salon and it vents out of the panel just aft of the windows. It seems to be a tidy setup but the 34 cabin is already smallish and that unit is just one more thing taking up space and something else that needs to be secured while underway.
When we had a 34, I installed a built in unit (Dometic, I think) to cool the salon area. I was a bit small to do the whole boat (10-12k IIRC) but we didn't do much marina cruising and prefered anchoring out where there was a breeze so it wasn't a big issue. If we were to have kept the boat, I would've added a 5k unit under the forward berths , which would've used the existing cooling pump and would have made it a simple installation. I,personally, am just not a fan of portable units on a boat. But then again, anything is better than being uncomfortable.

 

[psneeld]

Awe Shawn....it if still all works, you now have a boat that can make ice in the salon in the summer in Florida and cook meat in the winter (sorta).....

To the OP, every boat can benefit from temporary or permanent fixes for heat or cool, just depends what gyrations you are willing to go through and what is enough "to do the job"? Just choose between the least expensive or the least amount of work or what is the "very best" solution that is great, money is no object, and adds significantly more to the boat with the least amount or negatives. Often a hard choice, but sometimes pretty easy.

 

[OldDan1943]

I am docked just a bit south of Hollywood, between Ft Lauderdal and Miami.

I installed 12vt compartment fans so as to stir up the air. I have 3 fans in the saloon area and two in the S/R. All fans are located close to the A/C outlets.
I consider them a ‘expendable’ so I keep one or 2 spares onboard.

What you are proposing, portable A/C units, in my feeble mind, is a last resort.

Granted I do have a small ceramic heater, with fan, in the store room, I bring on board in the winter, if necessary.
The reverse cycle A/C just doesn’t seem to cut, it at times. I have 2 installed resistance heater built ins, which peg out the 30amp boat, but sometimes I just want a little more direct heat so I shut off one or both installed heater and rely on the one small ceramic heater.
LOL Cooking a Thanksgiving meal can be a challenge on a 30amp boat, especially if it is cold. That’s a different story. SMIRK
Finally, put a ‘solf start’ on your A/C unit(s). That helps a bunch too.
I think I am done.

 

[boomerang]

Awe Shawn....it if still all works, you now have a boat that can make ice in the salon in the summer in Florida and cook meat in the winter (sorta).....

To the OP, every boat can benefit from temporary or permanent fixes for heat or cool, just depends what gyrations you are willing to go through and what is enough "to do the job"? Just choose between the least expensive or the least amount of work or what is the "very best" solution that is great, money is no object, and adds significantly more to the boat with the least amount or negatives. Often a hard choice, but sometimes pretty easy.

The system(s) you installed are like most of the rest of the systems you did...err on the side of overkill! When we got caught in the arctic blast headed South last Christmas, the temperatures dropped down into the mid-teens and the waterway was a skating rink. While stuck at Atlantic Yacht basin,the reverse cycles in the aft stateroom and salon kept up plenty warm the whole time. While underway, the diesel heater and engine bus heater kept us warm without having to start the generator. You incorporated enough BTU's in that 40' boat to heat a small neighborhood! I think Liz must've said "thank you ,Scott!" about 100 times during that trip.

 

[OldDan1943]

1. Inspect the duct work for sharp bends and kinks. Find a sharp bend, buy a fixture to smooth sharp bends. Based upon my experience, 2X45 is far better than one 90.
2. Inspect the splitter in the duct to fwd SR and the saloon. If it is not a smooth transition, put in a Y. Adjust the flapper as necessary to balance the output.
3. Install compartment fans.
4. See if you have room for a duct booster fan going to the fwd S/R. I dont have room so I cannot tell you effect. Wire the fan so it come on and off with the A/C.
5. See if you can enlarge the ‘in’ and out of the A/C

I suspect you will feel a big difference.

Push come to shove, then and only then consider a new A/C perhaps the next size up. The new units have a smaller foot print and more efficient.

 

[PhilPB]

At the boat now and using my new "cheap" infrared thermometer:
Cabin, depending on surface, is 95°f - 104°f. Temp at the registers in both salon and v-berth is 75°f.

 

[OldDan1943]

At the boat now and using my new "cheap" infrared thermometer:
Cabin, depending on surface, is 95°f - 104°f. Temp at the registers in both salon and v-berth is 75°f.

A couple of compartment fans will really help. They help my situation.

 

[boomerang]

A couple of compartment fans will really help. They help my situation.

I wholeheartedly agree with small dc fans helping with the airflow and consequently the comfort of the cabins. We has one in our Mainship salon to move the flow of cooled/or heated air in the salon and a couple of portable ones in the stateroom and they helped immensely. Our current boat has 3 in the salon that the PO strategically placed that can be swiveled for use to help air flow and doubled as window defoggers , a mounted one in the aft stateroom plus a portable one and a portable one in the forward stateroom, all invaluable to us for comfort while onboard.

 

[OldDan1943]

When you measure the temp at the outlet with an IR gun and at a distance place in the cabin and there is a significant temp difference, you will benefit by installing compartment fans.
The MOST you can hope for is a 20 degree difference between inside and outside temps with the A/C. Not so sure about with heat.

 

[DBG8492]

I just moved an old 36 Marine Trader Sundeck from Pompano Beach to the Fort Myers side of the Okeechobee.

The onboard air isn't working, so we have two of the 8K BTU portable units inside - one in the aft cabin and one in the salon.

My advice is to go with a window unit if at all possible. That's the route we will take once we have a car down here. We are going on the hard soon anyway, so our on-board air would be useless even if it worked.

With both of the portable units running, it's okay for sleeping at night after about midnight. And it stays relatively cool until about noon. But for the 12-hour span between noon and midnight, it's only a degree or two cooler inside than out - the only difference is a slight change in the humidity right in front of either unit. The galley is down in this model and the fridge puts out more heat down there than the AC in the salon can overcome, so it only works at about 50% capacity using 5+ amps of power. if it wasn't for the solar, our charger would need to run all the time.

The biggest issue with them is the single hose. In that respect, the shorter the better. If you have a place to mount it where the hose can only be 12 to 24 inches from unit to outlet, you're better off because the hose is uninsulated and puts off more heat than you can imagine - right back into the room and right above where the condenser pulls air. The one in our aft cabin works better because of this - it's mounted about 24 inches from the window where it exhausts.

Another thing to consider is that both of the outlet panels leak water when it rains. I have tried to seal them up as best as I can, but they still leak. For us, it's not a big deal because we're heading for a big interior remodel, but for someone with good wood, it will be an issue.

Because you're looking to supplement your onboard air, you may have better results - but if you can't get a two-hose unit, my advice is to either find a way to insulate the exhaust hose as much as possible or hack it into a two-hose unit. There are a bunch of YouTube vids about how to do this and it's not as difficult as it sounds - it just makes the installation take up more room.

I plan to get at least a 20K BTU window unit and install it in the small aft hatch into the salon. It won't fit there because the door is only 22" wide and the smallest unit with that BTU rating is much wider, so I'm going to have to build a box that feeds into that hatch. I did something similar on our old sailboat, but it was in an overhead hatch, and routing the air into the cabin was a trick that I never completely unraveled. It worked but wasn't as good as it could have been. I am hoping that because this is a vertical hatch, it will be easier to route the conditioned air.

Good luck!

 

[SIBERNUT]

When I bought Phelps, there was a huge unit between the lower helm wheel and seat. PO had a panel fit in the stbd door opening. Never tried it, damn thing was so heavy and bulky it would have saved the Titanic if thrown overboard.