Courtney Thomas wrote:
I'm told that there are at least 2 types of boat heater, both of which
burn diesel; one using a blower to disperse the heat and the other
heating a circulating liquid.

What are the experiences of the group with both, please ?

We installed a Webasto Thermo-90 coolant type heating system and are
very happy with it.

http://www.webasto.us/press/en/am_tr...aters_821.html

The unit itself is amazingly compact, with a built in circulating pump,
combustion air fan, and control circuitry. I don't know if the system
overall is any more compact or easier to route than a forced air system;
the water piping & it's insualtion & expansion tank along with the heat
exchanger & fan, is quite bulky. With the added wiring & switches, I'm
sure it's more complicated & a bigger job to install.

Ours went on the aft engine room bulkhead where it is possible to access
the unit for maintenance (not that it should need any) and still have it
enclosed.

http://community.webshots.com/photo/...42005030smuktF
(plus the next two)

It's extremely quiet, unless you listen for the clicking of the fuel
pump, you can't tell it's running. The heat exchanger fans are not that
quiet but they are not obtrusively noisy... we leave the forward heater
fan running on low all night. The system heats up in about 10 minutes
and is putting out good warm air in 5 ~ 6 min. The furnace unit draws
between 1 and 7 AH, the fans from 0.3 to 5; so we could run the unit all
night on batteries when anchored out.

I see a few advantages to the coolant type system. It's a bit more
efficient. The heaters can be installed in a wide variety of places...
we have 5... so we can have the heat on full in the head, for example,
and only a little warmth in the aft cabin. Ours is not (yet)
cross-connected to the engine to run on engine heat, but I also think it
would be a big advantage to be able to heat the engine up to operating
temp more often over the winter. BTW the mfg'er does not recommend this
cross connect as it can have flow problems not to mention air pockets or
leaks that would not damage the furnace but would be disastrous for the
engine.

Hope this helps.

Fresh Breezes
Doug King