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Schooner Captain
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Discussion Starter · #1 ·
So, one of the items i am trying to overcome is deciding on a heat system.
hydronic, or hot air.
Hydronic has many advantages, distributed heat, longer life, hot water.
The disadvantages are cost, you must buy the unit, plus hose, plus radiators, plus fans, plus thermostats, plus expansion tank. It uses more power. It also takes a very long time to install.

Hot air has been known to have a short life, and use more fuel. It also requires less power, and easy installation.

our use will only be on cold nights, other times we will be in favorable climates, and if it is bitter cold we will run the generator for reverse cycle heat, or electric heat.

So my question is:
How many of you have used the air heat units, and how long did they last?
This is not the primary heat, and at the dock, we use the reverse cycle heat.

we will be on anchor more, but will follow the nice weather...
 

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Agree on the reduced cost of forced air vs hydronic, but wonder if installation (esp routing of hoses vs larger diameter ducting) is truly more difficult for hydronic outside installing the radiator units. Seems the other advantages would make it worthwhile in the long run.

If use is truly going to be limited, a central space heater, esp a 'diesel stove' can be very effective although perhaps less so on a boat of your size at 48ft.

I'm a tad leery of the typical Espar type air heater as on so many boats listed for sale that have them, they are often non functional. As with anything, though, steady use and proper maintenance goes a long way.
 

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Running 3/4" diameter water hose can be way easier than running 3" diameter air hose that can't have sharp bends.

I bought a boat with hydronic heat and love it. It also ties in nicely with the engine for heat and hot water while underway.
 

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I'm surprised to hear of early failures on hot air systems. The Webasto AT2000 on my boat is 28 years old and works great. I did replace the exhaust and some ducting recently, and it needs periodic fuel filter changes, but otherwise it is a reliable unit.

What is the normal failure mode?
 

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Schooner Captain
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Discussion Starter · #6 ·
not going to start a new topic for this, but can a 24 volt heater be converted to 12v? I have found some nice 100,000BTU heaters, all 24 volts. as i want to heat the cockpit as well when cold, 100,000BTU will be a nice size.
 

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All of the parts for the Webasto are easy to source and replace. The fan is $295 retail, around here (Seattle) it would be pretty easy to get for $230-$250 through an installer.

12V vs 24V: You'd have to look at the parts diagram for the system.

I do have to wonder what the fuel consumption of a 100,000 BTU heater would be. The Webasto/Espar heaters used on boats are typically 10% of that. 100,000 BTU is a bigger heater than what heats my 1800sqft house.
 

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Schooner Captain
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Discussion Starter · #8 ·
the exact unit i am looking at is 85,000btu, and burns 0.8GPH. how often it will run is another story. I was only planning to use it to take the chill off the boat in the mornings, and i will use it a lot in the polar trips.

True, most home heaters are about 100,000BTU in the north east. But your house is insulated. My cockpit is not.
 

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Courtney the Dancer
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I installed a hot air system (Wallas) because I didn't have room for the individual radiators at the locations available. Running the 3" ducts was easy, but I had lots of room and I could see that being a real pain (impossible) in many boats. As far as reliability goes, I've only had it for about 4-5 years (no problems or issues, completely dependable and it is used a lot) so can't really comment. I like the low power draw of the Wallas.
 

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Schooner Captain
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Discussion Starter · #11 ·
wood stove, inexpensive, simple installation, reliable, multiple fuel options, inexpensive.
Its a good option, in fact i gave the wall mounted diesel heaters a lot of thought.
Issue is they do not put out enought heat. I want a warm cockpit too.
 

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I don't see a great solution for a heated exterior cockpit, even 100,000 BTU will just be a quick way to burn through fuel.

If you had a pilot house that would be one thing, but from your blog it looks like your boat has a hard dodger and sometimes a bimini.
 

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Schooner Captain
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Discussion Starter · #13 ·
I don't see a great solution for a heated exterior cockpit, even 100,000 BTU will just be a quick way to burn through fuel.

If you had a pilot house that would be one thing, but from your blog it looks like your boat has a hard dodger and sometimes a bimini.
I am making the front half hard enclosed, and the back half soft enclosed.
If i didnt have that mast in te way, the whole thing would be a hard enclosure.
 

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cruising all I can
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been using mine for years, center cockpit, full canvas enclosure, the woodstove will blast you out of the cabin! open the companionway and heat rises into cockpit. also greatly reduces condensation and as a bonus you can cook on it.
spent the winter aboard last year in the Chessy,even use it underway. only drawback I have is it is dirty, you smell like woodsmoke.
 

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Had bulkhead mounted diesel drip on T 37. Hated it. Moisture level in boat. Only local heat.
Had espar forced air in PSC 34. Adequate in small boat but noisy and needs fans/ tubing runs which seriously compromise storage lockers. Heat not even.
Have hydronic wabasco in current boat. Love it. Quite, three zones, even heat. Only issue has been thermostats( not wesbasco). May end up replacing them. Like furnace not in living space. Like plumbing runs are very narrow unlike air ducts. Like having hot water whenever.
Have AC as well so can do reverse cycle. Run hydronic in preference. Much nicer especially if sleeping.
 

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IMO, and I am a professional HVAC designer, hydronic would be best and easiest to install. You can use a Pex tubing PEX Tubing , ThermaPEX PEX Tubing , Radiant Heat PEX Tubing , Wirsbo PEX Tubing , Radiant Heat - PexSupply.com and, forces air hydronic toe space heaters K42 - Beacon Morris K42 - K42 Kick Space Heater Toe space heaters have integral T-stats to turn fans on when the water comes up to temp. And if you have access to the underside of the cockpit floor or seats, in floor/seat radiant would work great. Everything you need to know and calculate what you need can be found here... PEX - Radiant Heat - Radiant Heating - Plumbing Supplies - PexSupply.com

Sorry, I have never used or designed for a boat application, but Pex is made for piping hot water and can be used with glycol, is very veritable and reasonably priced.

Edit: I am in no way affiliated with Pex.
 

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Also, as you know, hydronic can be connected to your engine cooling water to get free heat when under way. Here is a propane fired tankless instant hot water heater. It has the regulator and hose ready to go, just connect to tank. Water Heaters | Tankless Water Heaters - Gas | Eccotemp L10 High Capacity Tankless Water Heater | B602208 - GlobalIndustrial.com

And here is a 12V hydronic to air exchanger http://www.go2marine.com/product/20172F/radex-hot-water-forced-air-heater.html?WT.srch=1&WT.mc_id=gb1&utm_source=googlebase&utm_medium=productfeed&utm_campaign=googleshopping&gclid=CKC0o4KRprwCFeh0QgodLwMApg http://www.suremarineservice.com/REAL-fan-heaters.aspx
 

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Also, as you know, hydronic can be connected to your engine cooling water to get free heat when under way. Here is a propane fired tankless instant hot water heater. It has the regulator and hose ready to go, just connect to tank. Water Heaters | Tankless Water Heaters - Gas | Eccotemp L10 High Capacity Tankless Water Heater | B602208 - GlobalIndustrial.com

And here is a 12V hydronic to air exchanger Dickinson Marine - Radex Hot Water Forced Air Heater Sure Marine Service, Inc. | REAL Hydronic Air Handlers
I've heard of some serious insurance related issues with the propane tankless heaters, looked at a boat a few years back that had had it ripped out for that reason, couldn't get coverage? Could be they are approved now. The size/location of the venting seems to limit installation options.

Like the idea of hydronic despite added costs..

Looked at the links for the heat exchangers.. bulky units that might be difficult to install under bunks or floors...

Out: are yours similar? or more compact versions?
 

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The smallest toe space heater, in only 120v (.45 amp), are 12" wide, 4" tall and 13" deep. Squirrel cage, two speed fans and wiper quiet. Having a nice toasty floor is the best. The toe space do not come in 12V. I looked up replacing the C frame 120 motor with a 12 VDC, but I am not finding any. The 12 VDC heat exchangers are a bit bulky, but you won't need many. The one I posted link to is 10" wide, 5: deep and 7" tall. Maybe I missed the size of the OPs boat, but I assume if he is considering heat, the boat is sizable and can handle the space requirements.

As far as the propane hot water heater goes, this is only one easy option. I would also assume the OP already has means of creating hot water. But the heater I posted does not involve gas piping, has all the fail safe bells and whistles. Electronic ignition with prooffer, water flow proofer, high temp shutdown and in a heat shielded case made to be wall mounter. and is setup to be used exterior. I was running this installation scenario through my head and was thinking it does not need to be used very often and could be a removable exterior instillation and stored when not in use. When needed you could have water quick connections and temp. mount near the propane tank. This heater also needs 120v to operate, but it is a transformer 120 and heater uses low voltage, I'm sure it could be modified to use 12VDC.

This was just a suggestion, as you know there are many means to create hot water for a hydronic system.
 

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IMO, and I am a professional HVAC designer, hydronic would be best and easiest to install. You can use a Pex tubing PEX Tubing , ThermaPEX PEX Tubing , Radiant Heat PEX Tubing , Wirsbo PEX Tubing , Radiant Heat - PexSupply.com and, forces air hydronic toe space heaters K42 - Beacon Morris K42 - K42 Kick Space Heater Toe space heaters have integral T-stats to turn fans on when the water comes up to temp. And if you have access to the underside of the cockpit floor or seats, in floor/seat radiant would work great. Everything you need to know and calculate what you need can be found here... PEX - Radiant Heat - Radiant Heating - Plumbing Supplies - PexSupply.com

Sorry, I have never used or designed for a boat application, but Pex is made for piping hot water and can be used with glycol, is very veritable and reasonably priced.

Edit: I am in no way affiliated with Pex.
Most domestic hydronic kick space heaters have a pretty poor form factor for the hull curvature in boats as they are usually quite deep designed to fit under a deep & flat kitchen cabinet.. A 12V squirrel cage, in that configuration, would also be hard to come by and you'd now likely exceed the cost of a 12V hydronic air handler..

There are plenty of hydronic air handlers/exchangers available in 12V. In Europe they are more plentiful than here but shipping kills you.

Hamilton Marine has a slew of "bus heaters" that can easily be adapted to hydronic use but draw a bit more DC than one would like at anchor. They can be noisy but a DC fan speed controller can be added to keep it quieter and reduce DC draw..

If using PEX in a hydronic system be sure it as a hydronic heat rated PEX or what is called a vapor barrier PEX. Heatway Onix or similar will likely be the easiest tubing to work with on a boat because it is far more flexible than standard hydronic PEX.

ITR the folks who make the Hurricane Hydronic Boiler also have a slew of air handlers.

Dickinson also makes their line of Radex air handlers...

A bus heater, like the ones from Hamilton, off the engine, will supply PILES of cockpit heat. The lobstermen who fish winters here in Maine pretty much all use them...
 
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