# Cabin Heater



## Jeff D from CT (Jan 26, 2021)

Hi Im new to sailing and have a Pearson 31-2. I wanted to buy a heater for early and late overnights. I heard about "mybuddy" its an indoor propane heater that uses 1lb propane tanks and it can warm 300 sf. Would you recommend using it or is there something better/safer. My boat mechanic didn't like the idea of propane, even though I have a propane stove and stern rail grill. Thoughts?


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## hpeer (May 14, 2005)

We have Espar units. But these Planar heaters are getting good reviews and are much less costly. 

They are heads and shoulders over Mr Buddy etc.


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## CLOSECALL (Dec 11, 2012)

I'm not saying the buddy heater is a good idea, but I use one when away from the dock. But not when I sleep or leave for more than a moment. It is an open flame after all.


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## paulk (Jun 2, 2000)

Your mechanic is right. The small tanks are not included in the boat's propane safety setup. People die when the tanks leak or when the flame gets blown out for whatever reason.


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## midwesterner (Dec 14, 2015)

When using any kind of heater like the ones mentioned above, make sure to have a CO2 detector on board, and provide for a little bit of ventilation. People have died in cabins using these kinds of heaters.


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## Jeff D from CT (Jan 26, 2021)

paulk said:


> Your mechanic is right. The small tanks are not included in the boat's propane safety setup. People die when the tanks leak or when the flame gets blown out for whatever reason.


Thanks so much for your insight and feedback. Have you ever used a cabin heater.


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## SanderO (Jul 12, 2007)

Espar forced air diesel fired heaters are terrific but spendy. It draws fuel from the main diesel tank and requires an exhaust hose for combusted gases... very very hot... You run a few ducts to where you want heat, set the thermostat and your boat should be toasty and dry. It's quiet and safe and invisible. The install is not terribly difficult... but it does take some time to plan and execute a few basic tools.


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## CLOSECALL (Dec 11, 2012)

Anybody installed and used a planar heater?


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## SchockT (May 21, 2012)

CLOSECALL said:


> Anybody installed and used a planar heater?


A friend of mine installed one. He had some problems with it initially but that turned out to be due to mistakes he made on the installation. Since he corrected them it has worked well.

Heaters like planar, Espar and Webasto were originally designed as parking heaters for the trucking industry. The marinized version are just kits that include stainless exhaust pipe and fittings. You can save a lot of money if you source the heaters themselves through trucking supply houses rather than marine sources.

Forced air heat could be challenging to retrofit on some boats. You need to find an appropriate location for the heater, and then figure out how to route the 4" duct to where you want it. I have discovered they also consume quite a bit of power if it is cold out and they run alot.

Another option would be a bulkhead heater like a Dickinson or Force 10. They are like having a small fireplace in the cabin. Then you just need a flue vent through the deck and a fuel supply. You can either pump it from your main tank, or have a day tank closer to the heater. They are cheaper and easier to install. You can get propane, or even solid fuel models.
















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## Minnewaska (Feb 21, 2010)

I have a Mr. Buddy, which I bought to heat the cabin, while on the hard and doing winter projects. Scares the heck out of me to see that panel of hot flame. I can easily see something accidentally being ignited. Haven't used it since. One certainly would never use it underway. In the shoulder seasons, we use electric space heaters in our stateroom that has a tilt shut off. We run it on the low setting to avoid over taxing the boats wiring. At anchor we have heat pumps (reverse AC) that we can run, when the generator is running. One trick I've yet to try is a 12volt electric heating blanket.


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## hpeer (May 14, 2005)

The first question is how are you going to use it?
1- while sailing or just in the hook or at dock or on hard?
2- while sleeping or while puttering around?

If it is while sailing then there are few choices beyond the diesel hot air heaters. All others are too sensitive to heel or down draft.

It using while sleeping then you really need to separate combustion air from ambient air. No joking about it. That means some kind of permanent installation with a chimney- minimum.


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## pdqaltair (Nov 14, 2008)

Jeff D from CT said:


> Hi Im new to sailing and have a Pearson 31-2. I wanted to buy a heater for early and late overnights. I heard about "mybuddy" its an indoor propane heater that uses 1lb propane tanks and it can warm 300 sf. Would you recommend using it or is there something better/safer. My boat mechanic didn't like the idea of propane, even though I have a propane stove and stern rail grill. Thoughts?


The exhaust goes in the cabin. You breath the CO2 and there will be less O2. Moisture will make everything feel damp and the windows will sweat.

Put in a real heater, even a P9000. But yes, installing propane is complex.

You can also turn the stove into a vented heater. There was an article in Good Old Boat. Practically free, quite safe, and no exhaust in the cabin. I was using mine yesterday.










stove top vented heater


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## SanderO (Jul 12, 2007)

hpeer said:


> The first question is how are you going to use it?
> 1- while sailing or just in the hook or at dock or on hard?
> 2- while sleeping or while puttering around?
> 
> ...


I got the Espar as a kit... but from a marine supplier. I think you can find it for less from a truck parts supplier. It cost me about $1,500. So this is not inexpensive. But the heat is lovely and it's quiet and keeps humidity down as well. It has a T stat and goes to a "low" mode when the design temp has been reached.

Of course you need fresh air for an enclosed cabin... even your breathing in a seal boat could lead to oxygen starvation. So it's a good idea to have so fresh air vent... and the gas ratios will naturally maintain, It's a good idea to have a gas sniffer alarm in any case.

The cockpit lockers have common air with the bilges... and the engine bilge has an exhaust fan as well. The are fresh air grilles/vents inside the coaming cubbies. This is a path for air exchange (entry) into the bilge / locker air And the cabin heater is mounted in a compartment aft of the engine and batteries and uses the air in the bilges/locker spaces for combustion.... There is an insulated stainless steel flex hose for hot combustion gases to / thru the transom.

I run the heater sailing or at anchor when heat is desired. I have been used diesel fired forced air heat for 30 years.


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## chowdan (Nov 11, 2015)

I have both espar and a dickinson alaska. I much prefer the dickinson. 

Everyone talks great things about the espar, and I will second almost all of it but everyone keeps the negative things out of their comments.

Espars burn ALOT of fuel and also burn ALOT of power. When mine is in turbo mode, we draw 9amps, when in high it's drawing 5.5amps, when in 'low' it's drawing 3.5amps. mine runs non stop, it's rare for it to shut off, though that's likely due to the fact that we like the boat a bit warmer than normal (72-75). 

The Espar burns about .15/gallons an hour on low, roughly 3.8g/24hrs

My dickinson alaska floor mount heater runs on low 24hrs a day, burns roughly 1.8g/24hr period, and uses zero electricity. I do have a fan installed near the top that burns .5 ah so roughly 12amps per day.

The Espar heater is like adding another fridge or more to a boat and running a 4inch ducting through the boat isn't the best IMO.

If I had the choice and I was determined to not go with a gravity feed system, I would go hydronic. You'll burn just as much fuel, just as much power but you won't have massive holes through bulkheads and you'll have hot water and a warm, dry, radiant engine that will act like a thermal mass block


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## SchockT (May 21, 2012)

Yes my Webasto forced air heater burns quite a bit of fuel and power when it is cold outside, but we mitigate that by turning the heat right down overnight and throwing a heavier blanket on the bed. There are a number of ways to improve the efficiency of the heater. Mine is installed so that it draws 100% outside air, heats it and blows it into the cabin. Not very efficient when it is near freezing outside. At some point I will modify the ducting to draw return air instead of outside air. Also the supply air ducts are uninsulated so a lot of heat is lost into the voids where the duct runs go. It also doesn't help that my boat is not insulated!

Hydronic does seem to be a nice option since hoses and wiring are easier to run than 4" duct, but I suspect they would be enev more power hungry. Not only does the burner use power, there is the water pump, and the fan coil in each zone you want to heat.

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## Minnewaska (Feb 21, 2010)

chowdan said:


> we like the boat a bit warmer than normal (72-75)


If the thermostats are accurate, that's pretty warm, if it's freezing outside. I find, in shoulder seasons were it may be 40 outside, no matter what I run, it's hard to get the cabin above 68degs. With the most basic warm clothing (ie pants, long sleeves, something on one's feet), it's perfectly comfortable for us. I bet it would be a dramatic reduction in power and fuel consumption, for just that little change in target temp. Most of our boats have near zero insulation.

When it drops below freezing, at night, it can get hard to maintain a cabin must above the low 60s and I'll admit that's chilly. We close the door to our stateroom and run an electric space heater, which is toasty in that small space.


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## bigdogandy (Jun 21, 2008)

Jeff D from CT said:


> Hi Im new to sailing and have a Pearson 31-2. I wanted to buy a heater for early and late overnights. I heard about "mybuddy" its an indoor propane heater that uses 1lb propane tanks and it can warm 300 sf. Would you recommend using it or is there something better/safer. My boat mechanic didn't like the idea of propane, even though I have a propane stove and stern rail grill. Thoughts?


FWIW - and all of you northern sailors are gonna laugh - but I have a Little Buddy heater and use it whenever the temps go below about 50 and I'm anchored out. When I'm at the marina I use an electric space heater if it gets cold.

It works great - but you do have to be reasonably careful with it. I only use it when the boat is anchored, have a dedicated spot for it that's out of the way and not likely to get gear or something dropped on it, and I turn it off before I go to bed. I've also got a smoke / CO monitor and leave enough of a crack in the companionway for some air to come through.

Have used it when it was as cold as high 30s and it keeps the cabin around 60. Only takes a little while to warm the place up again in the morning.

If I lived up north the cost and complexity of a diesel heater may make sense, but winter in Florida usually lasts about 10 days that are spread out over 4 months, so this option works for me. YMMV


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## roverhi (Dec 19, 2013)

Have used a propane canister heater on the boat in SF. Not serious midwest cold but very effective in temps into the 40s. No problems with venting only complaint is it ate up the little canisters in around 5 hours so was expensive if you are buying new.


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## hpeer (May 14, 2005)

Espar power and fuel consumption both vary with model. If you don’t state the model and if it is hydronic or hot air then the comment has less value.

Also it you are evaluating just while anchored/docked or if you run it while sailing.

Also motor boat or sail.


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## Jeff D from CT (Jan 26, 2021)

hpeer said:


> Espar power and fuel consumption both vary with model. If you don't state the model and if it is hydronic or hot air then the comment has less value.
> 
> Also it you are evaluating just while anchored/docked or if you run it while sailing.
> 
> Also motor boat or sail.


I have a sailboat and only wanted to use heat when hooked to a mooring, just to warm up the cabin before bed. Would never fall asleep with it going or while sailing, I have enough to worry about. Thanks for everyone's input.


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## SchockT (May 21, 2012)

hpeer said:


> Espar power and fuel consumption both vary with model. If you don't state the model and if it is hydronic or hot air then the comment has less value.
> 
> Also it you are evaluating just while anchored/docked or if you run it while sailing.
> 
> Also motor boat or sail.


Obviously the bigger the heater the more fuel it burns. We are talking about consumption relative to a small portable heater, or a bulkhead mounted heater.

Even the smallest forced air unit will heat a boat better than a small portable, but it comes at a cost in both energy and fuel. That's the point.

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## SanderO (Jul 12, 2007)

I've had two different generations of Espar forced air heating... a D3L and now an AIrtronic 4 both used the same 3 ducts...one in the head, in the salon and one in the aft cabin.

The fuel consumption is like .1 to ,2 gal /hr. I do sleep with it on and I don't use it in winter except to warm the cabin if I am working there on a project. It's used in the Spring and Fall from March to November. I think I paid about $1,500 for the "kit / parts" and did the install which was not difficult but it does require running duct, cutting in grille outlets, running insulated combustion hot gas exhaust thru the transom, mounting the heat, running the fuel line to the main tank and mounting the inline fuel metering pump, the electronic controller and the thermostat and running the wiring harness and lastly 12v fused power. When I up graded everything new went where the old stuff was... and I used the old ducts and grille outlets.

I don't run it when sailing except when I sailed with crew to Bermuda in October from LI Sound. It was very much appreciated, It's most appreciated sleeping and having breakfast in the morning.

I love the heater and it's actual cost has been $100 per year and the fuel cost is negligible. The only service issue was a burnt bower on the D3L... Airtronic4 has been OK so far. It's pretty hi tech and not something you can do much with except burn some kerosene to clean the glow plugs (I never do). 

No open flame.... very safe.


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## hpeer (May 14, 2005)

The OP has responded that he wants occasional heat in the hook with no intention of sleeping with it on. 27’ boat I think. For him a simple propane bulkhead heater would be a decent solution.

SanderO, we also have an Espar D4 and live it. We were live aboards in Delaware. It kept the boat (44’ center cockpit) livable down into the single digits. But I would close everything not needed and sleep in heavy bags. Here in NC with temps down to 28 it has been fine with all spaces open. No ducting to aft cabin but it stays a nice sleeping temp. This is our home and we really need good quality heat.

We do use it when sailing. Coming up from Beaufort I got soaked and frozen. But the cabin was warm and provided gery much needed relief. I also have a D4 on my small boat in Newfoundland. And you can bet that thing gets used when sailing. When you have freezing fog and ice bergs it is super important. How Mike Rutherford did what he did amazes me.

Anyway, unlike the OP our boat is our home and our needs are different. I would consider a Planar as a replacement, much less expensive. If I were to fall into the lottery I would consider adding a second unit for the aft cabin and to add redundancy.


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## SanderO (Jul 12, 2007)

hpeer said:


> The OP has responded that he wants occasional heat in the hook with no intention of sleeping with it on. 27' boat I think. For him a simple propane bulkhead heater would be a decent solution.
> 
> SanderO, we also have an Espar D4 and live it. We were live aboards in Delaware. It kept the boat (44' center cockpit) livable down into the single digits. But I would close everything not needed and sleep in heavy bags. Here in NC with temps down to 28 it has been fine with all spaces open. No ducting to aft cabin but it stays a nice sleeping temp. This is our home and we really need good quality heat.
> 
> ...


You raise the very valid issue as to why one wants heat, how one sails their boat and where they are sailing, and what is the climate where they are sailing... add in size of boat and budget and the matrix means many different solutions.

As I noted... boat was sailed in LIS / Southern NE... and from early Spring into mid Fall. I/we spend lots of nights on board... we don't day sail. I did live aboard in the Caribe for 4 years and one in LIS... Obviously in the tropics heat is not needed.

Out heater is used MOSTLY for sleeping and early morning... but not exclusively. If we are spending a Fall weekend aboard and not sailing... the heater is on 24/7. But we normally don't have the heat running when sailing. It's there when needed and very much welcomed. No fun being cold and bundled up with multiple layers of clothing.

edit: Espar is used in March, April, September and October weekends...perhaps 20 evenings plus some day use.

I don't think a forced air heater system makes sense for a boat smaller than 30'

If you can afford the luxury... it's money well spent.


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## BarryL (Aug 21, 2003)

Hello,

I have an old Coleman catalytic heater that runs on the small propane cylinders.

Something similar to this:


https://www.walmart.com/ip/Coleman-SportCat-Catalytic-Heater/13228604



I use is rarely, but when I need it, it works very well. I have used it on my current boat and on my previous boat. If you use common sense you will be fine. 
-Make sure nothing combustible can come on contact with the heater
-Make sure the heater won't tip over, or if it does, that it won't damage anything
-Have a smoke and CO detector (can get one unit that does both)

No boat I have ever been on was so airtight down below that I was worried about the heater using up all of the oxygen. My previous boat had two dorades with no way to close them. My current boat has doesn't (unfortunately) but it's very easy to leave the companionway hatch open 1/2" to get some fresh air into the boat. I admit that I have slept with the heater on (and woke up very cold when it ran out of propane). Usually I use it for an hour or two when I am puttering around my boat in the winter.

If I needed heat often (say 5-10X a year) then I would invest in something better. However, I use my heater maybe once a year. So for MY use, a cheap catalytic propane heater makes good sense.

Barry


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## pdqaltair (Nov 14, 2008)

A direct vented heater running at 8000 BTUs will consume 0.38 pounds of propane per hour. This is 0.0086 #-mole per hour, or 10ft^3 O2. Air is normally 21% O2 and levels below 19.5% are considered dangerous OSHA), so 670 CFH ventilation is the minimum requirement, assuming the air is well mixed (which it probably is not. So about 1500 CFH or 25 CFM.

A tightly sealed boat could be dangerous in as little as 10 minutes. According to testing (PS) a 3" dorade in a 5 knot wind, pointed RIGHT into the wind is about 1500 CFH. At a 30 degree angle it is 5 times less, or 5 times too little. The wind could be much stronger or less, the angle could be greater or less, and the vents could be larger and more numerous.

So no, assuming a boat is ventilated enough is not reasonable. You need a breeze you can feel at the ventilation point. You are also either changing the cabin air every 15 minutes with fresh cold air, or you are breathing air below the OSHA O2 limit.

Just numbers, please feel free to check them. Obviously, a tight cabin is more energy efficient, and I have NEVER had a boat I could not make draft-free.


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## Minnewaska (Feb 21, 2010)

pdqaltair said:


> A tightly sealed boat could be dangerous in as little as 10 minutes.


When I bought the Mr. Buddy for some winter work years back, I ran it down below for hours. Neither it's O2 sensor, nor the onboard CO alarm went off. After several hours of work, my face was flush and I felt out of sorts the rest of the day. I don't think I ever used it again.

Use of unventilated open flame heat sources, in enclosed spaces, are illegal in some States and I think in all of Canada.


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## BarryL (Aug 21, 2003)

Hey,

What about a heater that is only 1500 BTU?



Amazon.com





pdqaltair said:


> A direct vented heater running at 8000 BTUs will consume 0.38 pounds of propane per hour. This is 0.0086 #-mole per hour, or 10ft^3 O2. Air is normally 21% O2 and levels below 19.5% are considered dangerous OSHA), so 670 CFH ventilation is the minimum requirement, assuming the air is well mixed (which it probably is not. So about 1500 CFH or 25 CFM.


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## arf145 (Jul 25, 2007)

I use a Buddy to heat the cabin in the evening the few times I overnight in the late fall. It does the job nicely. But I would never sleep with it running, and I store the 1 lb cylinders out in my propane locker when not in use. For the few times that I need heat, I could never justify installing a heating system.


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## pdqaltair (Nov 14, 2008)

BarryL said:


> Hey,
> 
> What about a heater that is only 1500 BTU?
> 
> ...


You'll get about 1500/3.41 = 440 watts of heat, which is not much, just a little more than a body puts off futzing around the house. A stove burner, for comparison, is about 7000 BTU. Portable electric heaters are typically 4400 BTUs.

With ventilation, it would knock the chill off a really small cabin, and not do much in the cold or a larger cabin.


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## pdqaltair (Nov 14, 2008)

For comparison, the stove-top heater I describe is about 6000 BTU, and that is just right for a 24' boat in cold weather, with minimal ventilation. At 45 degrees with the boat buttoned up, I might turn it down to 2000 BTU after the boat is warmed up. But that is with no ventilation and an insulated cover on the companionway.


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