Which Heater Is More Efficient?

Question: Could you please address the fuel consumption of forced-air bus heaters vs. the Refleks?

Answer: An accurate comparison of fuel consumption and relative efficiency between the two technologies would require equipment and time we don’t really have at our disposal. However, since both systems burn with an essentially clear exhaust, indicating good efficiency, and diesel fuel has a fixed amount of available heat per unit of volume, I think we can assume that their base efficiency is very close to identical. But the air bus heaters lose a lot of heat through their ducting, as much as 20% in a cold bilge, I’m told, and in addition, more fuel must be burnt—unless the boat is fitted with a wind generator and the breeze is very steady—to replace the electricity used by the bus heaters. Bottom line, I would expect the Refleks to be a clear winner in overall efficiency.

See this post for a general comparison of the Refleks and Eberspacher heaters.

{ 2 comments… add one }

  • Paul December 15, 2013, 11:48 pm

    Having had both heaters installed on our last boat, and spending two winters in Annapolis Md (not much of a winter compared to PEI) I can say that using the espar whilst under way and the Dickinson heater at anchor, works great. However, I may remind everyone that a bulkhead heater also loses a lot of heat out of the chimney.

    I’d have to give the Espar the nod as to which was more efficient. The Dickinson Alaska was rated for 16000 btu and the espar 11000 btu, but the espar definitely “felt” warmer. We had a circulating fan for the dickinson, but it never outperformed the espar.
    We already have one espar for the new boat, and will get a second espar for the second hull too. But if we didn’t have a Cat, we’d also have a dickinson if we had room for the chimney. There’s nothing better than cruising in a cold climate, when it’s cold, as long as I’m warm while doing it.

    Paul from PEI, Canada.

    Reply
  • Ray Durkee September 21, 2014, 10:18 am

    I am not sure where one would use 75 Ah of electricity with a forced air heater–that sounds really high even for a Webasto or Espar????. I have used a Wallas 30 D for nearly 20 years (I am on my second unit) and the thing uses 10 amp draw at startup for a few minutes, but more like an amp or two once it is running–depending on the setting. I agree that these units are not maintenance free and that it takes some guts to do it yourself, but I have learned over time. Also, I realize that Wallas units are not marketed as heavily as others but I have had very good luck with mine and consider it one of the essentials of cruising life. I even used it during a couple years cruising in Central America—nothing like it to dry the boat and everything in it out. Absolutely essential now that my boat is in Maine in order to take advantage of the great Fall sailing. ScanMarine folks are supberb support folks. The Wallas unit is specifically made for boats and is made in Finland.

    Reply

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