Prior to installing the kerosene heater (which heats the aft cabin and aft head only), we looked into
FIVE ALTERNATIVE SOLUTIONS;
#1. Replacing our current Webasto HL3003 with a new forced air diesel heater
Benefits: Reduced draw on battery (approx 20-25% less at max setting). Reduced fuel consumption (approx 25% less at max setting). More control over settings (our current heater is either off or on full power). Can be fitted into our existing system of ducts. No new chimney needed. Uses same fuel as engine. Can be used while sailing/heeling.
Disadvantages: Cost (especially Webasto and EberspÃ¤cher, wheras Planar is less expensive). Does not supply hot tap water. Still draws about 10-60 W, depending on heat setting. Some noise.
#2. Changing to water heater
Benefits: Reduced draw on battery (approx. -50%), Reduced fuel consumption (approx -30%). Can be hooked into our hot tap water supply. No new chimney needed. Uses same fuel as engine. Can be used while sailing/heeling.
Disadvantages: Cost. Requires new distribution system + convectors. Still draws about 10-40 W.
#3. Kerosene heater (brand: POD)
Benefits: No, or minimal (1.2 W), draw on battery. Uses same fuel as lamps (we use our kerosene lamps every evening because we like them; it’s the brass, open fire thing). Almost silent. Cheap fuel (about 20% cheaper than diesel). Can be used while sailing/heeling.
Disadvantages: Smell (though not a lot, assuming that you set the wick at the proper level). Requires new chimney and new distribution system. Does not supply hot tap water.
#4. Propane/Butane heater (brand: Truma)
Benefits: Uses same fuel as cooker/oven. Can be used while sailing/heeling.
Disadvantages: Very expensive fuel (about 3 times the price of kerosene/diesel) – which is why we did not look into this further. Requires new gas installation.
#5. Diesel heater (brand: Glembring and Refleks)
Benefits: No, or minimal (1.2 W), draw on battery. Uses same fuel as engine. Almost silent.
Disadvantages: Requires new chimney and new distribution system. Does not supply hot tap water. Can not be used while sailing due to heeling.
In the end, how you weigh the different pros and cons depends on how you use the boat. For us, the wish to be able to anchor for a week in winter with no engine running required to produce electricity is an important aspect (we have a 12 V 400 A battery bank). In the end, that, combined with the cost of the Webasto and EberspÃ¤cher products, is what made us settle for the POD heater. Only later did we find the Planar brand heaters, which are about 50-70% cheaper than similar Webasto/EberspÃ¤cher, although the Planar heaters draw about 13-25% more amps, depending on the setting.
For us, even with the advantageous price of the Planar, replacing our forced air diesel heater would not have achieved the goal (no, or minimal, battery draw). But we are definitely considering the Planar for the future since it barely costs more than servicing a Webasto/EberspÃ¤cher.
IMPORTANT TO KEEP IN MIND
When at anchor, and even more so when sailing, it is sufficient to heat the aft cabin and head (volume approx equivalent to a 25ft boat). The salon is difficult to heat when sailing, since crew passing up and down the companionway result in most heat being lost. Also, we rarely have people staying in the forepeak, nor use the forward head. Consequently, our basic heating requirement is about 1 kW. However, the possibility of occasionally heating the salon while at anchor, and even the forepeak, has some value and requires an additional 1 kW, which is the minimum setting on the new forced air heaters.