What type of heat?

[yukonbob]

http://www.macgregorsailors.com/modt/in ... ?view=1465

Here is where ours is mounted with aluminium backing plate. Through the forward head bulkhead and vented straight up through the deck (3/4" hole). Plumbed in from the anchor locker, down under the V berth and out just below the heater. Heater has built in O2 and pilot sensor (no power required). We use a five pound propane tank as out main source (singles for back up if we run out) hung off the front with a large padded caribeener and tied to stop it from sliding back and forth and lasts four to five days running 24 on low. It does make it a little difficult to use the head while it is on and we both have been burned a number of times, take the good with the bad I guess

[Gater Dunn]

lots of wood up here and I like the smell of burning wood, this unit is what I'd put in.

http://www.lfsmarineoutdoor.com/dickins ... eater.html

[Tomfoolery]

There was a ceramic heater on West Marine's site that's relatively efficient for under $100.

FWIW, all electric heaters are 100% efficient. Even the energy into the fan motor, if it has one, eventually becomes heat, as friction eventually stops the air from moving. Some heaters may be quieter than others, or have better controls or thermostat, or whatever, but every joule (1 watt for 1 second) through the wires becomes heat in the cabin.

[BOAT]

been using heater buddy for 6 years

[seahouse]

To clarify, Wypsyjac-
Ceramic heaters are no more efficient than any other electric heater. All electric heaters are 100% efficient- that is to say that 100% of the electric energy that goes into it is converted to heat (even if you count the heat lost from the resistance of the cord). In fact, even an incandescent light bulb is a 100% efficient heater. So spend more money for other features, but not for any “extra” efficiency that is advertised.

Also, Yukonbob –
I noticed that the website claimed that the propane heater produced less humidity than a diesel burner. Given that water (moisture) is a by-product of all combustion, and that they both vent their exhaust to the exterior, how then can one be claimed to produce more moisture in the heated space? If someone knows the answer to this, I’d sure like to know it.

Propane has a higher energy content than diesel (BTU’s -high-school chemistry) and is non-toxic, diesel is a mix of many toxic chemicals (and the exhaust can, on occasion, find its way back into the enclosed space). So the ready availability of diesel is one benefit among lots of other disadvantages.

Hey Mac-a-tac.
Because the products of combustion (water included) are released to the interior (unlike the above mentioned stoves), the buildup of moisture will be considerable. Until, that is, when the point is reached that all interior surfaces are heated up to a point where condensation no longer happens, and then when the rate of evaporation is sufficient (with required air exchange of exterior air) to dry them. A tough thing to bring about if the relatively uninsulated hull happens to be sitting in cold water, and the outside air temperatures are low. That could be at a high temperature.

Exterior cold air, even if it is moist, will be heated, expand, its relative humidity reduced, and will thus reduce the humidity of the interior space. So, some ventilation (which you need in any case) will be helpful, but a balance needs to be struck between letting in cold air and keeping the humidity down.

- Brian.

[seahouse]

Oops tkanzler - you posted while I was writing...

All electric heaters are 100% efficient

...and word for word, too!

We both agree, it must be true, and therefore it is disqualified as a "little known fact".

[Hamin' X]

The Wallace stove seems ideal for the boat but very expensive and would cause my full enclosure to get smaller.

Expensive for a heater maybe, but you are getting a forced-air heater and a cook stove in the process and the fuel (kerosene, or mineral spirits) is readily available everywhere. Exhaust is vented outside, so there is no condensation in the cabin and oxygen comes from outside, so the is no depletion of that in the cabin. Not sure about the problem with your full enclosure, please enlighten.

~Rich

[Hamin' X]

Oops tkanzler - you posted while I was writing...

All electric heaters are 100% efficient

...and word for word, too!

We both agree, it must be true, and therefore it is disqualified as a "little known fact".

Except for heat pumps that are driven by electricity: Within certain temperature ranges, they are more than 100% efficient.

~Rich

[Whipsyjac]

Thanks Seahouse and Tkanzler, so with electric energy in nearly equals energy out, its energy storage that's the trouble.

My main goal in adding a heater would be to reduce humidity safely, which is why for me propane combustion in and of cabin air is not attractive. The Dickinson and Wallace heaters look good but expensive. The wood/charcoal one seems to be middle of the road, but it presents the problem of having a very hot surface in a confined space with kids.

Gater Dunn, where would you mount that little beauty in an ?

How about exterior propane combustion to heat water which in turn runs through a heat exchanger in the cabin with a thermostat and fan? Sounds like something that's probably marketed already....mounted at the stern where most guys have their propane tanks.

Hmmmm,

Willy

[seahouse]

Oh Oh HaminX! - don't get me going on heat pumps! They certainly can surpass unity - but there is often a vast chasm that exists between the claimed efficiency vs the real-world efficiency in that industry.

I've seen some marketers even refer to ground source heat pumps a "geothermal" heating. A complete misnomer and a deliberately fraudulent misrepresentation of the product.

Of course, our discussion was regarding electric resistance heaters.

- B.
On edit: In all fairness, I should point out to the casual reader that the very large number of independant variables that exist with heat pump installations and climates makes it difficult to accurately and consistently measure their input and output efficiencies.

[Hamin' X]

Most things are just paper horsepower, agreed. I do use an air source heat pump in my home and it works quite well, as most of the time our outside temps are between 25ºF and 40ºF in the winter. Had a frog get into the computer board in the outside unit and in the process of frying himself, took out the board. Two weeks on order and on back-up electric heat the whole time. I certainly noticed the difference come billing time.

~Rich

[seahouse]

Hey Rich - Yeah, air-source heat pumps can't be used in our locale without having a second auxilliary heat source (so they're not too common here) for those (more frequent here) days when it gets really cold outside and their efficiency drops. Or when a frog gets caught in the board. Yikes!

They are more commonly used here for heating pools in the summer.

The wild effeciency claims I've seen have been made for the ground-source heat pumps.
-B.

[yukonbob]

Also, Yukonbob –
I noticed that the website claimed that the propane heater produced less humidity than a diesel burner. Given that water (moisture) is a by-product of all combustion, and that they both vent their exhaust to the exterior, how then can one be claimed to produce more moisture in the heated space? If someone knows the answer to this, I’d sure like to know it.

Propane is considered a wet heat because people who have a propane setup (up here anyways) go for the whole sh~t and get a propane range as well as water heater furnace ect. Propane being very clean as burning of fossil fuels goes can be burnt open flame inside without being directly vented. The force ten although is vented it is not a sealed unit and does have an open flame that vents outside.

[Tomfoolery]

Thanks Seahouse and Tkanzler, so with electric energy in nearly equals energy out, its energy storage that's the trouble.

Exactly equals, except for the bit of cord that isn't inside the cabin, but that's not the cord's fault. The heat out of the whole system will exactly equal the electric energy into the system, the system being all of the supply wiring plus the heater. I have a few cheap-o space heaters (like ~$10) from the BORG that I use to heat my garage when I need to do work out there. I run a total of 5 of them (4 off my welder circuit subpanel, one off the original garage receptacle) for a bit over 6kW of heat (a bit over 21,000 BTU/hr). The super cheap heaters put out just as much heat as a ~100 heater of the same rating, but I don't care what happens to the super cheap ones. I keep one nice looking one that cost $20 to use inside the boat when working on it during the winter or at the dock.

That efficiency, by the way, is what frosts me with the marketing of 'Amish fireplaces' and all other sorts of snake oil nonsense. They're only 'more efficient' in the sense that you can turn the rest of the house down at the thermostat and sit in front of the heater, but you can do that with a Harbor Freight parabolic radiant heater (where you get the near-instant benefit sitting in the infrared beam) for a tiny fraction of the purchase cost of an Amish fireplace or other uber-pricey gadget. And electricity usually costs many times as much as fuel oil or gas for the same amount of heat from the heating equipment (100% for electric, less than 100% efficient for the others, not counting heat pumps). But a $10 heater still puts out the same amount of heat for a given amount of electric energy in as any other type of resistance heater, and the infrared toaster-type heaters like those with the parabolic reflectors eventually heat the air in the room the same as a convection heater (oil filled radiator, those little cheapie forced air units, the expensive ceramic types, etc.). As long as you don't shine them out a window, that is - infrared works the same way as visible light in that if you shine it out a window, that's where it all goes.

How about exterior propane combustion to heat water which in turn runs through a heat exchanger in the cabin with a thermostat and fan? Sounds like something that's probably marketed already....mounted at the stern where most guys have their propane tanks.

My FIL's 42 ft trawler had a system like that, with a boiler in the engine room and fan coil units in a number of places. I believe it was single zone for the water (presumably with antifreeze/anti corrosion additives) and only the fans were switched on/off as needed via a local thermostat. I wouldn't have a clue as to how you'd cram such a system into such a small boat, though.

[Tomfoolery]

Oops tkanzler - you posted while I was writing...

All electric heaters are 100% efficient

...and word for word, too!

We both agree, it must be true, and therefore it is disqualified as a "little known fact".

I can rest in the security of knowing that at least one other person agrees, confirming my prejudices, reinforcing my righteous biases.