The mechanic who installed our Eberspächer diesel heater last year proposed we instead install an engine-driven heater exactly as yours, and in fact insisted we check out a similar installation he did a few years ago on a sistership docked next to us, which we did and were quite impressed with. It is a brilliant idea.

In his case, the heater came from a truck (a Renault, I seem to remember?), and even had the truck controls for fan and temperature. The mechanic sang its praises and emphasised the much lower cost! Installation on our boat would have been a breeze, from what I saw.

I think it is an excellent idea for people permanently in cold climes and/or who motor significantly for one reason or another; we just don 't quite fit either criteria on this particular trip we now are in.

It certainly would be an excellent emergency backup if all else fails, and something we would definitively install if conditions warrant.

I am from the cool climate of Maine and can categorically state that installing an engine heater (commonly called a "bus heater" in the US) was one of the best values for the buck I ever did on the boat. Assuming you have a suitable place for it, the installation is easy and inexpensive. Anytime we 're motoring we can quickly warm the boat up, and it helps take the damp out as well. Below is the link to our unit in case it isn 't clear what these are. They basically work like an auto heater, tapping into the engine 's coolant system and blowing warm air out through 2 or 3 ducts.

https://shop.hamiltonmarine.com/products/heater-28-000-btu-12v-w-2-outlets-heater-only-22263.html

Great write up by Dick and Ginger on the Reflex. We love ours, especially the non-use of electricity, quiet operation, and the considerable heat it puts out. We never go above the lowest setting and that is sometimes too much heat. I would add a couple small points to what Dick and Ginger wrote. We consulted with the same woman in Sparndam and she told us our occasionally downdraft problem can be helped with an insulated section of chimney above deck. This helps keep a cold mass of air from lodging in the pipe and disrupting the flow of air. Also, the H shaped chimneys are better than the "yachtsman" cap for preventing down drafts. Finally, the brown compressed wood fiber (found in grocery stores in the Netherlands under the name Aanmaak Blokjes Bruin) makes for a very easy light. Simply stick a small chunk on the end of a metal rod, light it, fish it to the bottom of the heater, then pull the burning chunk of fiber off the rod.

Hello Hasbun,
May your unit be forever flawless.
Interesting design features your Amel has. Thanks for the explanation.
Agree that reverse air has its drawbacks, especially as I believe it to get increasingly compromised in its ability to deliver heat as the temperature drops: just when you want it most.
My best, Dick Stevenson, s/v Alchemy

Hello Dick,

I believe all Amel Super Maramus came pre-ducted for heating. Those who did not option the heater at the factory got instead two very powerful fans, in series, at the location of the heater, and this functions as a forced fresh air ventilation system (Amels have no dorades). Even now, post-heater installation, if we sail for prolonged periods in disagreeable weather with all hatches closed, we sometimes turn on the Eberspächer in ventilation mode, for a while, to replace and freshen the air below decks.

Eberspächer offers two silencer models: one for the inlet, and one for the outlet(s). Two different part numbers. Yes, installing the silencer ducting for our sleeping cabin did reduce airflow to our cabin (together with noise); but this reduced airflow has no perceived impact on the heater 's ability to quickly heat up that cabin.

We have heard these units can be fickle and are afraid it may start acting up at the time when it is most needed. We do have emergency heating via one reverse heating a/c unit and a couple of a/c units with electric heating, but it is brutally inefficient to run the generator for this purpose.

Our unit has been flawless so far after its first operational season.

Thanks for the advice and comments!

Hi Hasbun,
Thanks for your report.
I am glad you are (mostly) happy with your Espar. I also did not know that there is the possibility of a silencer option. Good knowledge. I wonder how they solve the likely increase in back pressure which could be a problem? I have lived with the D5 and its predecessor for almost 15 years now and know it well.
What is your boat that had the foresight to run ducting etc.?
Agree, the Espar heat is great heat.
Also agree, that in many ways a radiator system that warms with circulated water checks many important boxes. The down side might be that it is not “fast” heat (and in that similar to the heat from a Reflex stove). The upside is it may be able to be linked into the propulsion engine’s water heater/colorifier system to provide heat when motoring. Also you report it much quieter which would be nice.
A couple of comment/suggestions:
For those who consider heat critical to their enjoyment of cruising, who are at anchor a fair amount, or cruise areas where service technicians might be problematic, a yearly servicing is advised. Waiting till problems arise might end up in lengthy periods till an experienced engineer is found. This yearly servicing costs 200-400 dollars (150-250 pounds) and necessitates removal of the unit from the boat. Doing this might not ensure never getting cold, but is what I (and many friends) do to ensure heat. Those friends who push the servicing interval found that not wise in the long run.
For those frequently at anchor/mooring (or just not with shore power), please note that, in cooler/colder weather, it can take 50-100 amps per day to run an Espar. That is a lot of amps to replace.
Regardless of what heat decision one makes, ensure you have appropriate alarms (CO, smoke etc.) well situated in your vessel. This goes double for those who choose to have this sort of heat on when they sleep. We, on Alchemy, let the boat go cold at night. The Espar, in particular, is very fast heat and takes the edge off a cold boat quickly in the AM.
Lastly, I can effect reasonable maintenance/repairs on most equipment on Alchemy. This has been essential for us who wander to places with few resources. I gave up on the Espar. It was just too complicated with too many safety sensors. A cruiser much handier than I who considers heat mission-critical to his wandering essentially carries a second unit. If serious about the maintenance/repair, I would suggest talking your way into the shop where servicing on your unit is being done and take many notes/pics and ask lots of questions and buy spare parts.
My best, Dick Stevenson, s/v Alchemy

Going the opposite direction, we installed an Espar (Eberspächer) Airtronic D5 last July.

For us, the sole downside is the noise from the large central fan. Our installer did not advise us that Espar sells silencers for the intake and for the outlet conduit(s). Given our installation design, there is no space for the inlet silencer, and though there are three outlet conduits (to aft, to main, and to forward cabins), we were only able to last-minute fit a silencer for the aft cabin, which is our sleeping cabin. This silencer made a very significant difference, and obviously it is the only one genuinely important for us. Had we known ahead about the silencers, we probably would have re-designed the installation.

We had a chance to compare our installation to that of another OCC member 's in Barcelona, and theirs was absolutely quiet, using a system (from the same manufacturer, I believe), which heats water, and this water is circulated to radiators in the various cabins. What a great installation!

Anyone installing an Espar should consider the wireless remote control (with screen). We chose this option which enables us to control the heater from our sleeping cabin, and to schedule the heater to, for instance, turn itself on every morning at 5 am. The standard wall control unit that comes with the Espar at no additional charge, and which we installed close to the nav table, allows no scheduling, and although you can purchase an upgraded wall unit with scheduling, this becomes unnecessary if you get the wireless with screen.

I should note a Reflex should probably have been our preferred heating choice, had our boat not been ready from the factory for the Espar, i.e., all the conduits and outlets were already there and all we had to do was drop in the heating unit and connect diesel, power, and exhaust to it.

One innovation we introduced to our boat last winter was the electric heated towel rail in the heads!

We can run this 150 watt heater off the inverter but it is at it 's best when plugged into shore power. We left it on through the winter connected to a thermostat and it kept the heads frost and condensation free through the ravages of an Icelandic winter (where electricity is either very cheap or free).

It is wonderful to wander into a heated heads and great for drying towels and oil skins too! We opted for a very compact marine stainless steel version.

Clearly not a cruising essential but that, together with an electric blanket, has added a degree of comfort to our early season high latitude adventure.

Hi Simon,
Yes, that is a heating solution used by some friends and is a very nice (and powerful) solution when motoring. My interest was in those days and longer periods where we are at anchor. It should be noted that a Reflex stove can be used in most any motoring situation and is standard equipment on many fishing boats where they are putting out heat 24/7, albeit not with the ease of a car type heater. I wonder why I have not heard of car type heaters in fishing boats as their engine is going full time??
My best, Dick Stevenson, s/v Alchemy

Great post Dick and Ginger.

I know some members have experience of fitting car heaters to run off the engine 's cooling system which sounds a good solution when motoring. I think Milvena and Seewolf have fitted these very cheaply.

Boat heating is an important topic (for some of us) so I have created a new category on the Forum to accommodate it.
Simon

Dick Stevenson, s/v Alchemy

Refleks: Early days field report: s/v Alchemy               May, 2016
We have been in cooler/cold climates and do not like our season curtailed by ornery weather and cold. That said, neither do we in any way enjoy being uncomfortable: we like being warm and able to dry out. Being warm may not be mission critical, but for us, being able to get warm when relaxing and not underway is live-aboard-cruising critical. Our Eberspracher/Espar forced air diesel furnace amply met those criteria, but at the expense of a good deal of electrical energy usage, regular infusions of money/time/effort for servicing and occasional, though relatively rare, breakdowns which were beyond my capacities. This may be a personal irritant, but we also find it quite noisy.
After much research, I had been eying Refleks stove heater/furnaces for years, but had been unable to figure out an installation on our 40-foot boat (Valiant) of modest interior proportions relative to many modern 40 footers. I considered other stove-heaters. Most important, those with experience seemed to choose Refleks and always seemed happy. Also, among other more minor caveats, there were occasional reports from users of other stove-heaters of worries/problems leaving the stove going when unattended which seemed to not be a worry with the Refleks.
I finally had a plan and when near a Refleks dealer in the Netherlands that I had visited a few seasons earlier (Watersportcentrum de Rietpol in Spaarndam). There I received Ursul’s (extremely knowledgeable and experienced with Refleks) good housekeeping seal of approval on my idea. It helped immensely to have Ursul and the full line of Refleks stoves and accessories ready at hand and I spent an afternoon going repeatedly from store to boat and back with bits and pieces till it all “dry” fit. This was incredibly more effective to the design-on-a-napkin/order-by-mail method I had anticipated doing and the process enabled me to “fine tune” the design and installation in ways that would have been difficult otherwise.
INSTALLATION:
After all the above work, installation was straightforward and the directions were more than adequate. Mine was particularly easy as I can gravity feed from my fuel tanks and thereby finessed a day tank and fuel pump. I do not know whether this will be important in the future, but I installed my stove on a removable pedestal (3 inches or so) that will allow me to drop the stove and remove the chimney piping and stove with a good deal of ease as well as installing an additional fuel shut off valve.
USE:
We lit ours first try and have had little trouble in perhaps 30+ starts/uses. We have yet to use it in greater than steady 20 knot winds with higher gusts. It uses approximately 1 liter (quart) of fuel in 8 hours of use in its lowest heat output setting. We warm the boat on a higher setting (usually) and turn it down when the boat is warm. On our 40 foot insulated boat (modest interior volume) the lowest setting keeps the boat warm and dry in 5-10 C, 40-50F without a problem. Warmer outside temps have us cracking the hatches to keep from overheating. A fan directed over the chimney makes a large difference in getting the boat heated quickly. We also bought an Ecofan that sits on our stove’s top plate and circulates air. It works solely by heat and makes no noise. It is brilliant! Warmth in the boat becomes surprisingly evenly distributed over time.
The whole set up is a large jump in our happiness with heating systems as well as with redundancy. As I write this, we sit at anchor in Falmouth on a cloudy and damp 50-55 degree F (hatches cracked open) day with the boat comfortable on a liter of fuel and no noise, no smell, no fuss, no amp use.
CONCERNS:
Installation is shoe-horned into a space at the end of a 2-leafed table. The table is an island where, before the stove installation, there was just barely room for a small to medium sized person to squeeze through the space between table and bulkhead. The stove now lives in that cozy contained space. All dimensional set-offs were right at the minimal end to Refleks’ directions (or pushing the envelope a bit) and I was concerned about the woodwork around becoming overheated. I was also concerned about exposed metal surfaces of the stove being able to burn people.
Even at ¾ full heat*, which we use in the mornings to get the chill off more quickly, the woodwork becomes warm, but never so hot as to need to pull one’s hand away. (The Ecofan is always in use and, when getting going, we have a Hella fan moving air around the upper parts of the chimney distributing heat that might otherwise go out of the boat. These fans clearly make the heat less concentrated.) Even in such a closed space, nothing was over heated or been a worry. I was prepared to use shielding on areas of anticipated over-heat, but that has not been necessary to execute.
Protecting people was a priority. I used Refleks’ chimney shielding for the accessible parts of the chimney. Even at ¾ heat, the shield is never hot enough to burn, and one can let a hand rest on it. The body of the stove also seems to remain unable to harm at higher heat levels. There are places where a bad burn could occur, but at this stage, my estimation is that you would have to work to do so: very similar to the dangers of one’s cooking stove. The “cozy” installation placement, while perhaps not optimal for heat distribution sandwiched in as it is, does serve to keep the stove out of the way and far less likely to be “bumped” into.
We were concerned about smell. In what I suspect is well over 100 hours of run time, we have rarely noticed any smell at all. We are aware this may change in high wind situations, but are quite pleased so far. There has also been no interior dirt/ash/soot in the slightest.
DOWNSIDES:
Reports indicate that use of the stove/heater is limited to sustained heel angles less than 10 degrees. That said, they are used on many fishing boats that get bounced around a lot, but generally are not at sustained heel angles. For heat when sailing heeled over, the Eberspracher/Espar is hard to beat when it is 0 dark 30 and wet and cold outside.
The Refleks is also not “quick heat”. On a cold morning we close off the saloon and in 30 minutes the edge is off the cold and in an hour or more we are opening up the whole boat to spread the warmth. The Espar is much faster at warming the boat.
The above deck chimney is something that can catch lines and find ways of getting into trouble. Ours is tall (better draft) and we remove it when not in use and underway.
Some rare reports of sooty backdrafts usually attributed to an initial learning curve, but we have not experienced any yet.
Possibility of spilt fuel, especially on my gravity fed installation.
Jury is still out on what wind level will cause difficulty lighting or issues when lit such as blowing the fire out or blowing fumes back into the boat. My researches have not revealed reports like this, but they seem possible.
MAINTENANCE:
Minimal. Push a supplied cleaning rod through every few weeks and clean the burner trough of debris from the starter method one uses. Cleaning a filter as needed. Using a soot cleaning tablet every 2 weeks when the unit is used 24/7.
SUGGESTIONS: (please confirm with others)
We have a “cooking plate” top with a side chimney. Reports seem to suggest this design puts out more heat than the designs with the chimney out the top. Also, it is particularly easy to light as the plate is removable and so enables easier placement of the initial lighting medium. The top plate is also a brilliant place for the heat operated fan, the Ecofan. I suspect on some bored cold rainy day we will actually attempt to make a pot of soup on the top plate.
A wire “poker” can be an aid to positioning the burning starting medium to the area where the fuel is weeping in and this aids starting.
A Hella fan, or any of its type, circulating air over the top parts of the chimney as it exits the boat adds to overall heat output.
*We have a “cooking plate” model and plate temperatures at low heat are in the 280-320 degrees F (150 C) whereas at ¾ heat the plate rises to 540 F (280 C). Surrounding furniture have seen a high of 120 F (50 C) when at high heat output, but is usually in the 80-90 F (30 C) degree range.