Boat Heating Advice

Hi All,
We are in need of some direction regarding heating our boat.
We just purchased a 40ft Kha Shing sundeck trawler. We liveaboard in Seattle so heat is very important in the winter time.
The boat is equipped with an older Epar D4 diesel forced air heater (The orange one). The heater does not work at the moment and the service tech said that he would not work on diesel heaters of that era because they are unsafe to repair and put back into service.

We are currently using space heaters to keep the boat warm. We are on 30a shore power so that limits what we can do electricity wise. That being said, we are planning on converting to 50a 125/250 to better meet our electricity needs. We will be converting to 50a regardless of what heating option we decide on.

The electrician has told us that a very good way to go is to install 3 electric wall heaters on our boat similar to the King Pic-a-watt heaters when we do the conversion. one in the V-Birth, one in the main salon and one in our aft cabin to meet our heating needs. This would require a fair amount of retrofitting and cutting of our new boat in order to install these heaters, not to mention the $800-$1000 cost of the heaters themselves.

The other idea is to use the existing duct work that is in the boat and just replace the Espar heater with another diesel forced air heater. I've heard vary degrees of cost for a new Diesel heater. from $3500 for a new heater to $2000.

My biggest question is, in the long run, would it be better cost wise to run. Diesel heat or run electric?
We do have a generator so i believe we would be able to run both types of systems while on the hook. Although i'm sure running a genset at night would suck for sleeping.

Are there any other options to reuse the existing duct system besides diesel? Electric furnace maybe?

Thank you for any thoughts or guidence.

Abe

Welcome aboard. Not an expert on diesel heat so I will leave that to others. Good luck with your new boat.

I just watched this excellent vlog on YouTube. They replaced older heaters with inexpensive diesel powered units that distribute hot air via existing ducting. Check out the 2-part series:

I think the best solution is hydronic heating with a diesel boiler. The noise is minimal (mostly just circulation pump) particularly in the cabin areas, but the whole boat is comfortably warm.

However, if your existing ductwork is up to scratch then a new diesel forced air unit will be more cost effective. Running costs for electric can be high, even once you have the upgraded shore connection.

Just remember you will need to be either connected to shore power or have the generator running. When your cruising you will find you may want some heat some mornings even during the summer months.

We have a hydronic heating system and can run it off a 8D battery most of the day if need be. But they do not use heat ducts, they run small diameter hose (about 1") to carry the hot water to various heaters in the boat. We have 4 different zones and can heat each zone separately.

I suggest you attend the Seattle Boat Show coming up in January as there will probably be several vendors displaying various systems, plus they will be on sale. Maybe look into a heat pump as most of the new boats seem to have gone to them.

Option 1, 3 King Pick a watt wall heaters. Electric is quiet, clean and the set up you mentioned would give you 3 different zones for controlling temperature. Cost would be reasonable as electricity is cheap in the PNW. Down side, 3 electric heaters is 33 amps using up most of your 50a circuit. By going to a 120/240 50a setup you still have a second 50a circuit to run your hot water heater and other house needs. Remember 50a is max and not continuous. If you run at 50a for an extended time you will burn something up.

Option 2, modern diesel heater. You get a lot more heat out of diesel. Nothing warms a boat up like diesel heaters. Cost to heat with diesel is similar to electric. However diesel is noisier, can leave soot on the boat, more maintenance intensive and you have to have a fuel plan so you don’t unexpectedly run out.

I reviewed the video above and did some research on the cheap Chinese diesel heaters. There is a lack of safety information regarding boats. I am not calling them unsafe but I am not calling them safe. I see no support system behind them. If you install one and it lasts 10 years, great. If it lasts 1 year and then needs service, then what? If they are defective and damage your boat you will only have your insurance co to turn to. I am not going to call them an acceptable alternative. I reserve the right to change my mind when better information is made available.

To heat a 40’ boat in Seattle you will need 3 electric heaters. Problem is you only have 30 amps currently. This gives you 22amps for 2 space heaters and 11 amps for your hot water heater, the rest of your boat wants 2 amps. Now if you turn on a microwave or a hair dryer or any such heating appliance you will trip the main breaker. The other problem is that space heaters are not designed for continuous use and your 30 amp system is not designed for continuous 30 amp service. Meaning you can get by for awhile heating your boat with 2 electric space heaters but I would not try this for the whole winter.

Most boat fires in Seattle have been traced back to an electric space heater.

There is forced air heating and then there is hydronic. Forced air is when you heat the air at the source and then use 3-4” tubes to send the heated air to different parts of the boat. Force air systems are almost always diesel systems.

Hydronic system is were water is heated and then Pumped around the boat in 1” o.d. Hose to heat exchangers were a fan blows air through the heat exchanger. The original heat source can be either electric or diesel. In my case I have a hybrid which can switch between electric or diesel.

I feel hydronic is worth the extra money but it is not the only acceptable answer.

Other heat sources, reverse cycle heat pumps and wall mounted vertical draw diesel furnaces.

Heat pumps are efficient double as AC in the summertime and are expensive.

Furnaces such as dickens wall mounted units are reasonable in cost and very efficient but require a chimney be installed. You also run the risk of bumping into a hot stove.

Back to the original question of which way to go for the long run. Well that depends on how you are going to use your boat.

If you are just going to live on it and only take it out in July and August, go with the electric, very low maintenance.

If you plan to go boating April to October then you will be better off with diesel.

abe313 said:

Hi All,

We are in need of some direction regarding heating our boat.

We just purchased a 40ft Kha Shing sundeck trawler. We liveaboard in Seattle so heat is very important in the winter time.

The boat is equipped with an older Epar D4 diesel forced air heater (The orange one). The heater does not work at the moment and the service tech said that he would not work on diesel heaters of that era because they are unsafe to repair and put back into service.

Click to expand...

I would try cliffv (http://www.nwmarineair.com) or sure marine for espar repair in the Seattle area.

Go to Sure Marine and explain your situation. They are some of if not THE best marine heat resource in the country, and they are right in your backyard. I am guessing they will tell you to replace your forced air heater with a similar unit. Hydronic units are great but you already have all the air ducting run for forced air. Electric is a lousy option unless you never plan to leave the dock.
Figure out a good central location and install a radiator to scavange heat from the engine. People call these bus heaters or Red Dot heaters, Sure Marine has a bunch of options. That will give you a bunch of free heat anytime the main is run and will be a good supplement to whatever you choose for your main heat.

I agree. Go with a diesel furnace. I lived on my trawler through one winter. It is equipped with three Thermadore electric wall heaters front, rear and center as you described. When the outside temp dropped below 32f you couldn't keep the boat warmer than 65f inside. And when it got down in the 20's had to use a portable kerosene heater, which really stunk the boat up. Terrible experience. No insulation and lots of windows, heat passes through them like s*** through a goose.

I’m 48 feet, I love my d8 forced air, but thinking of adding a small hydronic for hot water on the hook in the morning without using the genny.

Electric has proven itself to be a great way to burn down the boat and a few others around you too. Electric heat is okay when you are on the boat and awake.

abe313 said:

We do have a generator so i believe we would be able to run both types of systems while on the hook. Although i'm sure running a genset at night would suck for sleeping.

Click to expand...

It'll suck for every other boat in the anchorage too. Replace the Espar using the existing duct work, diesel feed, exhaust. That will be by far the cheapest and most satisfactory solution.

abe313 said:

Hi All,
We are in need of some direction regarding heating our boat.
We just purchased a 40ft Kha Shing sundeck trawler. We liveaboard in Seattle so heat is very important in the winter time.
The boat is equipped with an older Epar D4 diesel forced air heater (The orange one). The heater does not work at the moment and the service tech said that he would not work on diesel heaters of that era because they are unsafe to repair and put back into service.

We are currently using space heaters to keep the boat warm. We are on 30a shore power so that limits what we can do electricity wise. That being said, we are planning on converting to 50a 125/250 to better meet our electricity needs. We will be converting to 50a regardless of what heating option we decide on.

The electrician has told us that a very good way to go is to install 3 electric wall heaters on our boat similar to the King Pic-a-watt heaters when we do the conversion. one in the V-Birth, one in the main salon and one in our aft cabin to meet our heating needs. This would require a fair amount of retrofitting and cutting of our new boat in order to install these heaters, not to mention the $800-$1000 cost of the heaters themselves.

The other idea is to use the existing duct work that is in the boat and just replace the Espar heater with another diesel forced air heater. I've heard vary degrees of cost for a new Diesel heater. from $3500 for a new heater to $2000.

My biggest question is, in the long run, would it be better cost wise to run. Diesel heat or run electric?
We do have a generator so i believe we would be able to run both types of systems while on the hook. Although i'm sure running a genset at night would suck for sleeping.

Are there any other options to reuse the existing duct system besides diesel? Electric furnace maybe?

Thank you for any thoughts or guidence.

Abe

Click to expand...

I have removed an old Espar. My next major task is to remove all of the ducts, etc and repair the woodwork at the outlets.

I use a diesel stove for cabin heat. Quiet, dry, economical. My installation cost for the diesel stove was comparable to a new propane stove, and gave me a major galley upgrade as well as providing cabin heat.

The Espar D7L had cost more in maintenance per yr than my 3 diesel engines, was still noisy, stinky and would never start properly on cold fuel.

I would never go back.

If you will not be going into "real" winter,,, 0degF some nights and staying in warmish Seattle you might contemplate a modest system.

The Dickinson line of oil (diesel) fired ranges will put out 15,000-20,000 BTU , which is 3 or 4 electric heaters worth.They are reliable silent and need no electric to function , so produce no electric bill , and work in blackouts.

Many will mount in the std cut out for a galley range so are easy to install.

A deck iron , smoke head ,smoke pipe and easiest a bladder tank for diesel to gravity feed the range .

It will burn 1 to 3 or 4 gallons of diesel per day temperature depending.
If it gets winter cold an electric heater can be run for a day or two.

In the past ( 1970's ) I sold Espar and other repurposed truck heaters , and most required maint the owners could not provide.

The Dickinson worked for liveaboards for a season Nov till May (the water is still cold in the spring).

The hydronic system I would chose today would be the Hurricane , as it is built for a boat not a diesel bus4


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.

The easiest solution is to replace the old Espar you have now with a new diesel forced air heater. You already have the ducts, fuel, exhaust, etc... to the old heater. Yes I’d replace the exhaust tube, but the rest should be good to re-use.

If you were starting from scratch there are advantages to both hydronic, and forced air, I have had both, but you are not starting from scratch.

Pick your brand. I have had Espar and Wallas units. I really like the Wallas furnaces myself for a forced air. They are quiet, and they modulate the heat output rather than starting and stopping. That makes for a very even heat. I have had my Wallas furnaces running 24X7 for six months straight for 7 seasons now. Yes they have taken some maintenance, but not a lot.

As far as diesel vs electric cost assuming that you have the shore power to support it is... and this is a rough calculation

Price per gallon of diesel divided by 30 is roughly the price per usable killowatt of energy out of a gallon of diesel. So of diesel is $3.00 per gallon that would roughly equate to $.10 per klilowatt hour (I can supply the exact math behind this if anybody is interested)

On my Bayliner 4788 I have 27,000 BTU of heaters, and they run pretty hard when the temp gets to be about 25 degrees. Less as the temps get warmer. That is roughly equlivent to eight thousand watt space heaters all running at the same time.

Here are some of the math basics for those interested.

1 galon of diesel has 123,000 BTU of energy.
Diesel furnaces are around 85% efficient so a gallon of diesel has 123,000* .85 or 104,000 BTU of recoverable heat energy. The rest goes out the exhaust tube.

1 kilowatt hour of electricity has 3412 BTU, and 100% of that is recoveralbe energy.

The math is easy from there.

Oh, since you are a liveaboard we have a great resourse specifically for liveaboards, and their issues. several of the contributors to this thread are members, but I’m not allowed to post a link here. Perhaps they could chime in.

For what it's worth, here's a post I did on another forum on the heater I installed in Alaska last year. If you're looking for a cheaper solution, it's a pretty good one:

Hi All:

I recently installed a VVKB Apollo-V2 heater on my 3218. It's a heater that is often used by truck drivers to heat their sleeper cabins when parked.

I was a bit worried about this because it's much less expensive that a Wallace or ESPAR or other brand of well-known diesel furnaces. This heater only cost about $500.

The bottom line: It works and works pretty well.

The downsides:

--It's a heater, not really a furnace. So, there is not thermostat that will automatically shut off the heater when the cabin reaches a certain temperature.

--Because it is designed for installation in an RV or big rig, you'll need to improvise a through hull for the exhaust. I used a stainless steel through hull that was slightly larger than the end of the exhaust pipe. I added some high temperature gasket caulking to make the fit air tight.

--It doesn't have a lot of accessories. I wanted to split the heat output to port one vent into the stateroom and one into the main cabin. The heater just comes with one length of 3" ducting and one vent. In the end I used a stainless steel "Y" from a motorcycle exhaust pipe to split the heated air output. I was able to use some heavy duty stainless dryer vent tubing as ducting and a search on Amazon turned up some vents that worked just fine.

--The controller shows codes, not clear messages. So, for example, when you turn it on it shows "A00" which means "Ventilation Mode," you hit the button again and it shows "A01" which means heater mode. There are other codes for the 5 levels of heating, etc. In other words, don't lose your damn manual so you can look up the codes.

-- Temp readouts are in C not F. Can't figure anyway to change this, although there may be.

-- The unit won't operate if tilted more than 30 degrees. I figured if I'm in seas where the boat is experiencing over 30 degree rolling or pitching, then I have more to worry about than staying warm.

--

With all these drawbacks, however, it was $2,500 cheaper than a Wallace, and seems to heat the cabin really well. It was in the low 40's in Cordova the first night I stayed onboard with the heater going. On the lowest setting it kept the cabin at a comfortable 69-71 degrees all night long.

I was worried about the temperature of the exhaust hose, so I took fairly elaborate precautions to cut large air gaps between it and any bulkheads, and wrapped high-temp insulation around points where it came close to anything. Turns out this was unnecessary. Even after hours of running the exhaust hose is just slightly too hot to touch with bare hands. Far below combustion temperatures for common materials.

For the record: I'm not associated with the manufacturer or reseller of this unit in any way.

You can buy these off amazon. Just search the model number.

Hope someone finds this useful.

Dave
Dave Stephens
2002 3988 "Chinook"
Cape Coral, FL

AND

1988 3218 "Raven"
Cordova, Alaska

(Yes . . 2 boat owner: A special kind of dumb!)

We are currently “living” on our boat in Vancouver BC. We alternate between:
1) a couple of space heaters at 500 watts each, the dehumidifier at 300 watts and the electric water heater at 1500 watts. So on the 30 amp circuit, I’m on he edge. The water heater isn’t working at 1500 watts all the time but it’s slow and essentially only 2 quick showers.
b) Webasto hydronic heating system, 3 zones. It gets the water in the tank REALLY, REALLY HOT! The hot water heater and space heaters are switched off.

Normally, we just run the number 1) when we are on the boat. The temp is about 60-62 F. Once the Webasto is at temperature, about 15-20 minutes, the fans come on the boat is instantly warm, 70 F.

As Kevin Sanders did, I also have a Wallas 40DT heater.
I got it 4 years ago, because of the great reviews, it's made in Finland, which is much colder than anyplace on the west coast and it's supposed to be the most quiet forced air heater and most efficient ( Scandinavia and Finland pay $8+/ gal of fuel).

But, I still haven't finished installing it yet.

In a cool climate like Seattle, a diesel heater/stove/boiler is the best way to be comfortable and dry. Any combustion device removes wet air as it burns. Electricity alone doesn't do anything about ventilation. I've seen many people close up their boat tight, run electric heat and then wonder why everything is wet or rusting.
Added insulation does wonders, both in comfort and reduced heating cost. No recreational boats are insulated for very cold weather.
I run a stove all winter. My humidity runs between 35-45 rh. Sometimes it gets too dry and I leave a tea pot steaming. I can heat with electricity, but it's twice as expensive with .07¢/kwh. Marinas usually charge double or more for power.

I'll confess to not having read the entire thread. But..... 3 electric heaters aren't going to cut it most winters. I live aboard in Seattle and speak from experience. This winter as mild as it's been I'm getting by on the 3 electric heaters most days, but not all. And sometimes it's nice to fire up the diesel heater just to get things toasty warm.

May already be mentioned by others, but a boat with only electric heat would be a non starter for a lot of potential buyers.

I lived aboard in Seattle for years, but it was a sailboat with very low interior volume and window area compared with most of the craft that this group have. A couple of electric heaters did OK, but even that little boat needed supplemental heat from the bulkhead-mounted kerosene heater at times. BTW, I'll never do anything with kerosene again! Ick.

We LOVE our Dickinson diesel stove, as did my late father-in-law who had one, too. The dry heat is wonderful, it's cheap to run, requires almost no maintenance, and doubles as a cookstove so efficiency increases. With the addition of hydronic coils, it becomes a source of heat for other spaces on the boat, too. Those "Red Dot" or bus heaters can be plumbed so that the diesel stove as well as the engine coolant can act as sources of heat.

BTW, here's a steal of a deal on some hydronic heaters: https://bellingham.craigslist.org/bpo/d/bellingham-hydronic-air-handlers/6758421069.html



As others have said, it's critically important to address air handling (moisture management) as well as simply air temperature. We do that by drawing in cold, dry air at one end of the boat and ejecting warm, moist air at the other.

Ahh memories...


The 40 year old wiring in my electric bulkhead heater caught fire when I was living aboard over in Lake Union. Thank God I was smart enough to have changed out the batteries in the cheap little smoke detector a month before. Best $1 I ever invested!

A little late to the party with these estimates, but....

Reading Sure Marine's info on Webasto heaters I'm estimating the OP's boat will need 40,000 + BTU to keep warm.

Using Rapid Tables online calculator BTU to KW 40,000 BTU = 11.72 KW
At 120 Volts and a power factor of 1 that comes out to 97.7 Amps when the system is running full power. Of course the heater won't be running full power most if any of the time. But it's apparent that it takes a lot of power to heat a boat.

Looking at it from the other end
30 Amp service running at a safe 80% load = 24 Amps
Each space heater tops out at 1500 Watts = 12.5 Amps
Two space heaters on high and you shouldn't run anything else

50 Amps is a bit better, you could run all three heaters but shouldn't run anything else

Two 1500 Watt heaters = 10,236 BTU
Three 1500 Watt heaters = 15,233 BTU

As I said in an earlier post experience shows me 3 electric heaters won't cut it on cold days. On a 40' Tolly liveaboard I run 2400 Watts of electric heaters, I pay a flat rate for electricity, and a 4 KW forced air diesel heater. For a total of 6.4 KW or 21,838 BTU of heat. Most winter days that's reasonable. This winter I've been able to use the diesel heater sparingly. But there were days in previous winters when I had to decide which cabin I wanted to inhabit and let the others get cold.

I'm sure there are engineers and electricians here that will find some fault in my estimates and come up with slightly different #s. But my personal experience demonstrates 3 electric heaters won't cut it in a typical Seattle winter.

Portage_Bay said:

A little late to the party with these estimates, but....

Reading Sure Marine's info on Webasto heaters I'm estimating the OP's boat will need 40,000 + BTU to keep warm.

Using Rapid Tables online calculator BTU to KW 40,000 BTU = 11.72 KW
At 120 Volts and a power factor of 1 that comes out to 97.7 Amps when the system is running full power. Of course the heater won't be running full power most if any of the time. But it's apparent that it takes a lot of power to heat a boat.

Looking at it from the other end
30 Amp service running at a safe 80% load = 24 Amps
Each space heater tops out at 1500 Watts = 12.5 Amps
Two space heaters on high and you shouldn't run anything else

50 Amps is a bit better, you could run all three heaters but shouldn't run anything else

Two 1500 Watt heaters = 10,236 BTU
Three 1500 Watt heaters = 15,233 BTU

As I said in an earlier post experience shows me 3 electric heaters won't cut it on cold days. On a 40' Tolly liveaboard I run 2400 Watts of electric heaters, I pay a flat rate for electricity, and a 4 KW forced air diesel heater. For a total of 6.4 KW or 21,838 BTU of heat. Most winter days that's reasonable. This winter I've been able to use the diesel heater sparingly. But there were days in previous winters when I had to decide which cabin I wanted to inhabit and let the others get cold.

I'm sure there are engineers and electricians here that will find some fault in my estimates and come up with slightly different #s. But my personal experience demonstrates 3 electric heaters won't cut it in a typical Seattle winter.

Click to expand...

The only part I find questionable is the need for 40,000 btu. You might be right. The amount of btu’s Needed will vary from boat to boat. Regardless I think we all agree, 30 amps is not enough and 50 amps is marginal.

Let’s not forget that the OP was looking at 120/240v 50a. Which would give him 100 amps. This would allow him to run 4 electric heaters which I believe would be adequate in Seattle.

If it was my decision I would have both diesel and electric.

I would recommend both Sure Marine and using a diesel hydronic heater.

We have hydronic (Hurricane) and love it. Easy to use, great output and a water heater loop. Ours has an engine loop as well so we have “free” heat and hot water when underway. Toasty warm.

As Delfin mentioned resale value would be better too. Electric heaters say “condo boat” to potential buyers.