After years of fighting with an unreliable diesel heater, we are very pleased with the Espar heater we installed in 2000. It is one of the bigger ones they make and keeps us toasty in all weather.
One thing we would suggest, though, is not to use the exhaust exit in the hull that they normally specify. In heavy weather this will be very vulnerable to flooding. We had Mike Bowden at Ocean Options, where we bought the heater, fabricate us a 4′ high chimney with a ‘Charlie Nobel’ type top that is braced to the stern rail. With this setup we can use the heater even in very heavy weather at sea—when a wick type heater would almost certainly blow back—which is, after all, when you want to be toasty below. The drawbacks of this type of heater are the substantial electrical use and complexity, but these are balanced by the convenience of just flicking a switch when we want heat, even at sea.
We have a Webasto 3500 and have used it in all weathers and when sailing and must agree with you: flick the switch and 5 mins later we are nice and warm. We sailed from Pontrieux to Morlaix on the Brittany coast in 2006 in F9 with snow storm and -11C outside. Inside in a woolly and a coffee at 25degs C (GREAT).
We have had he 5kW Espar since about 1998, first for heating while finishing the boat in Quebec, and since 2008 sailing.
Only real complaint is that twice it has failed to start. Each time, I took it to an Espar shop where they simply reset the control modue by plugging into their Espar “magic box” which linked to their computer. Cost was trivial, but I was lucky that there was an Espar shop nearby each time.
They said the problem was “too many restarts” True, we had, due to issues with air in the line from the engine.
I am considering buying the Espar “magic box” to fix myself, but they cost nearly $500. Does anyone know a better solution?
Hi Neil,
Sorry I don’t. In fact we sprung for one of the magic boxes for just that reason.
That very much depends on the size of your boat and the need to keep things warm. If you are in port or on a mooring in cold weather (like all winter long), clearly $500 is pretty minimal for assured, boat-wide heating…just add diesel and enough battery capacity/charge ability to run the sparker and the fans.
If you are “transient”, however, I really think warming up a single area, like the saloon with a bulkhead diesel heater, can be a better option.
We have a Mermaid Marine Air heat pump/A-C of 12,0oo BTU performance. It is considerably cheaper to get a second Honda 2000 (the “companion” model) to “kick” the AC March pump (which wants 17 amps to start and then the Marine Air unit and pump “fall back” to a manageable 6 amp draw) than to get an Espar/Webasto unit and to duplicate, as seems necessary, the entire insulated vent setup (I have tried to figure out without success if the existing MMA distribution setup could be Y-valved from a diesel heater).
A bulkhead diesel heater, if used to keep a central area warm on passage, might make more sense, particularly if you have adequate ventilation to keep condensation to a minimum in the under-heated parts of the boat. If you intend, as do the blog owners, to over-winter in fjords, you’re going to spend multiples of $500 on diesel itself to keep the boat warm, so you might as well go big!
Hi Mark,
We have a post here on the pros and cons of the various heating options.
The big benefit of furnaces like the Espar is that you can burn them when offshore, no matter the weather. I can’t tell you the number of boats I have met up north where the crew are freezing their behinds off because the can’t make the bulkhead heater work right at sea or they fear burning themselves or some a piece of gear on the chimney.
John, in the recent 24V part 2 column you refer to your existing Morgan’s Cloud 12V set up, which includes an 8kw Espar heater and that it keeps the boat toasty even with below freezing outdoor temps. I’ve had a smaller 5kw Espar on my 39ft boat for many years and I’m very happy with it, but I think the maximum temp differential it can manage is about 30 deg F, not enough for “toasty” when freezing outside. Maybe Morgan’s Cloud is well insulated? Excellent analysis of the 24V question.
Bob Andrew
Hi Robert,
Yes, MC is very well insulated with spray on foam so we have never been in a situation where the D8 would not keep the boat at 70F even when the ambient was well below freezing. In fact in Arctic Norway, where we were plugged in for the winter, three 1500 watt ceramic heaters kept the boat toasty, and we really did not need that many watts (4500), but used three for more even heat distribution (aft cabin boat).