How to size HVAC

[Stillraining]

OK Guys:



Looks like I have to replace my HVAC in the boat...Its hard to tell what size is currently in there..the Pro doesn't even know??



So they are trying to direct me to replace them with 9000btu units which would give me 18,000 btu combined....Is this good enough for the tropics? 41' tri cabin....If it cools at a rating of 9000 btu does it heat at that as well?



Also these are hydronic units...what ratio of heating compared to cooling can I expect out of our 43 to 46 degree water here in the winter? My curent system utilizes heat strips for the heater part.



Here are the units.



Webasto FCF Series ( Feel Cool Fast! )

Sure Marine

[Cruisingdad]

They will basically suck at 40 degrees water temp for heating. You are better off with space heaters or a moutned propane heater.

We have a 16000 and 12000 btu. ABout the same size boat. I think I could have gotten by with two 12's or maybe a 12 and an 8. However, the 12-8 combo might be tough to keep up with the heat during the summer as the deck gets very hot. If you can cover the deck, you are good for less. I will say that a single 16 will probably not do your boat, so I guess 18 would not be sufficient either.

Brian

[SVAuspicious]

I have a 12k and 7k BTU on a teak-decked 40' 22k# boat. It is not quite sufficient on Chesapeake Bay. I'd prefer a 16k and a 12k.

The heat works fine until the water gets below 40F, at which point I run the diesel forced-air heater.

In my experience propane heaters contribute to condensation and electric heaters get in the way. YMMV.

[tdw]

Still,

Why would you want air con in the PNW ?

edit - hmmm...am I confused ? am I an idiot ? quite possibly guilty on both charges.

[SailD]

If you're stuck, load the compressor up to max and measure the current draw. Then use that as a reference for the load on the new compressor, you shouldn't be too far out if you have that info then search the load on similar type compressors.

[Stillraining]

Thanks Guys!...I really appreciate the info.


Womby: Far from and idiot my dear friend..

It is an insurance replacement gig for one they cant get the old units to work now after the mishap ...but besides that anything to keep the wife interested in boating is fine by me...She is claustrophobic and even our no wind summers here in the PNW can make below decks pretty unbearable at times for her..knocking 20 degrees off the cabin temp can mean a lot especially right before bed in those conditions.

However rare thoes days might be around here...........around here isnt my ultimate goal..

I am leaning toward a 16 and a 9 acording to this information...Thanks again guys!