Reverse Air vs. Heat element?

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Billylll

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I am replacing both air conditioning units in my 40' Sedan Bridge. I was wondering if anyone had an opinion on the heating mode? I am seriously considering using units with heating elements only and not reverse air. I would think BTUs would be BTUs but the units I am looking at are 12,000BTU in air conditioning mode and 5600BTU when using the heat resistive element. I don't have to run the water pump when in heat mode with this set up. I am in the Northeast and would like to extend the season. Is this a good move or a bad move? I can handle the additional AC (shore power or Genset) load required by the heating element vs. reverse cycling the compressor. Please give me your thoughts, opinions and experiences if any.
Thank you. Bill
 
I can tell you that my reverse cycle heat works in pretty cold water. I was using it last weekend with the water temp. in the high 40's. It took about 5 minutes to begin blowing warm air, but once it did it was fine. I intend to keep the boat wet all winter but when onboard will use an oil-filled and ceramic heater when it gets way below freezing (and I have to winterize the A/C pump).

IMO reverse cycle heat makes the most sense in the MidAtlantic region because we don't see the extreme cold they have up North.
 
Strongly suggest reverse cycle as you can get as many BTUs heating as cooling. They work well down to 40 degrees water temperature and still provide heat lower than that.
 
You are in cold country. Get the reverse air, fact said, you will have twice as much heat. With water the reverse air works great all the time.
 
I have the heat element. It handles the cold quite well. I like the fact that I can still run my heat when the a/c side is winterized.
 
Just to clarify, reverse cycle doesn't "work great all the time." Houseboater is correct: most units are rated to produce heat with 40 degree seawater, and can produce heat down to about 35-36 degrees. After that, they blow cold and then go into the "low pressure" warning mode and shutdown.

We've been lucky in our S.E. Michigan boathouses this winter, the water has been warm enough to keep the rev cycles going. At this time last year, we had already put several months of usage on our space heaters.
 
This topic really does confuse me. because I know it's dependent on water temperature. Please someone correct me if I am wrong, the warmer the water temp. the warmer the air will be at the discharge with RC heat mode. With electric element heating the air temp. really won't change with water temp, just recirculating the ambient temp. in the cabin accross the heating element out the vents which should provide a more constant heat source? There has to be some sort of chart showing water temp. vs. heating temp output BTUs with reverse cycle AC units or have I got it wrong? I am really against using space heaters in the boat because I have read about numerous insurance claims and accidents in their improper use in boats. Thanks Bill
 
Given my druthers, I would use a heating element. I am disappointed there is no A/C w/ ceramic heat unit on the market. Or at least none I know of.

The biggest issue to me would be use. If most of the use is in a slip (yours or wherever you are visiting), I would go heating element. If your gennie can handle the load on the hook, I would go heating element. If not, go to an RC unit, but expect to supplement the heat when the water temp gets below 39*F.

Spent New Years Eve on a friends 42 Carver. Oh yeah...Happy 2007 to All...He has 3 RC units. As a liveaboard to save floorspace in the master stateroom he runs the RC unit. He uses a ceramic heater in the lounge. Heats the whole boat to 70+*.

In 2005, we had a few VERY COLD nights for central Virginia. He had to put an additional ceramic heaters in the master as the water temp got too cold to allow any heat to be drawn from it.

My $0.02

HTH
 
When I say heating element I am talking about a marine air unit or line of units that does air conditioning and either reverse air or a heating element but not both heat modes. So I am trying to make an intellegent decision and I am leaning towards the combination of AC w/ heating element and no reverse air. But I am still listening and remain open minded. Regards Bill
 
I know that Mermaid makes a either r/c heat model a/c and models with electric heat.
 
I can't provide hard numbers for you, but I CAN say that the amount of heat that r/c produces, even in cold water, is impressive. As Arks mentioned above, we too have found that it takes longer to get hot after startup. When the water temp is within 4-5 degrees of 40, our Cruise-Airs blow barely-warm for 5 minutes, maybe more, and then starts kicking out plenty of heat.

I can tell you that a 12,000 btu r/c system puts space heaters to shame. In fact, our neighbors got so much heat out of theirs in sub-40 water temps that they ended up opening a hatch in the middle of the night to cool off!

Do you know what to expect as far as seawater temps throughout the winter?
 
After the water tempature drops below 40 degrees, the danger is ice forming in the discharge hose. The A/C wrms the air by transfering the BTU's from the water to the air. IF the amount of BTS are removed lower the temature of the discharge water past 32 egrees, then slush forms and can clog the out stream. This may cause damage to teh unitu if it backs up into the exchange.
 
I've had my 18,000 btu unit working very well in 36 degree water. The gas cycle would be good to 23 degrees, but you of course couldn't pump the water.
 
Billy,
Reverse cycle should fit ur needs... The heating element type draws a tremdous load that why they are not used often. But like most have said heat up time depends on water temp. All reverse cycle units have a built in defrost mode... so after a certain run time it goes into deforst to prevent the condensor from icing over... But i would stick with a reverse cycle and if the initial start up of cold air annoys u... a small ceramic heater to just tmper the air at first would work great.

Rob
 
Go with the elements A bunch of reasons in cold areas A/C Ref man lic 2 states for yrs and yrs.
repairs , freeze ups, efficency below 40, RC in warmer climate hands down but you are not their.
 
Reverse cycle is a lot easier on your electric bill if thats a consideration. Reverse Cycle gives twice as much heat per watt of electricity used. Plus the fact that you have 12,000 BTUs per unit instead of 5500
 
I guess that is the real question do you really have 12,000 BTU of heat when the water temp is at 40 degrees or below? I am still on the line because my old AC units weren't working properly and I have never owned a boat this size I have nothing to base my decision on but opinions. Keep them coming.
Thank you. Bill
 
Bill,
UR in NJ... How long u keeping the boat in the water??

The reverse cycle will do fine as the water temp is still high enough to extract heat from. LAte December & January is when the water temp gets iffy... So how late in the season u really boating ?
Once the boat starts to warm up .... u will have pleaty of heat... units are rated at aprox 40 degree water temp. I forget the inside temp ... but there are alot tricks to get more heat out of the machines... The reverse cycle is the way to go...

Rob
 
You have a 1993 boat. HVAC units typicall last the life of the boat or at least 25 years. Did you have your present units back flushed and serviced?? whats the problem with them???
 
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