Originally Posted by Valiente
Is there a reason for choosing these "heat the whole boat" systems instead of a bulkhead or sole mounted heater like a Dickinson or similar? . . . I'm not trying to dissuade you, but rather to find out your thought processes. I find it interesting that many of us run engines that send sometimes scalding hot water out the stern and then build entirely other ways to heat our cabins.
We essentially live aboard most days from May to October, away from the marina whenever possible. On those cool Spring and Fall days & nights I have very little concern over power drain.
The maximum electrical drain for the Espar D4 is 3 amps - at peak load. The average is about 2 amps. We've slept at anchor with outside low temps in the low 40's & interior temperature at 68 degrees (Farenheit). Upon waking, our battery banks remained at 12 + volts. Therefore the system is well-suited for cruising sailors.
Our four separate cabin spaces and 7 ducted outlets (aft cabin, pilothouse, galley/dinette/salon, forward cabin), plus two eclosed heads, each with a damper controlled air register, are all well served by the D4 furnace.
The beauty of diesel fired, central forced warm air, is that ALL cabins are toasty warm, not just in the vicinity of a bulkhead heater. We do not need to run the engine for heat - it's quiet, energy efficient and very effective. Of course when on shore power there is no battery drain.