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What is the preferred heat source?-gctid781343

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    #16
    With 120V - 30A shore power the limit will be 3600 watts. That's a bit under 12,300 BTU total, assuming nothing else is run. In reality, you will probably have 3000 watts or about 10,200 BTU available; this is due to other electrical loads. 3000W is the max capacity of two plug-in space heaters (1500W ea). For comparison I have a 37' Bayliner with a lot less interior space than a 40' Bodega. My boat has an 18,750 BTU diesel furnace and I feel this is the minimum to keep the boat warm in sub-freezing weather. Note that his is 84% higher heating capacity than provided by 3000W worth of space heaters.

    With regards to a buddy-type heater. I've used them in my previous boats, but only when we were awake. I also had three O2 detectors installed on the boat: salon, and both berths. I personally do not like the idea of running a buddy heater off a standard propane tank on a boat.

    I think you have a couple of alternatives: a diesel heater or a propane heater. If your boat has an existing propane system, a propane furnace or heater may work best. I recommend the installation and propane feed be done following all current ABYC requirements. If not installed already, I recommend a propane detector/alarm be installed. A diesel heater may not be that hard to install. You will need to add a diesel tank, but that's pretty easy to do.
    1999 3788, Cummins 270 "Freedom"
    2013 Boston Whaler 130 SS
    Anacortes, WA

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      #17
      Portland Oregon has a electricity cost of 8.45 cents per KWH

      I'd be willing to bet that is within spitting distance of the cost of diesel as a heat source. (We can go over the math again if anybody wants to )

      If I were a liveaboard in Portland I'd be seriously considering electric for my heating needs.

      This might require an additional power inlet to the boat. It might require getting from the marina an additional power feed or upgrading the existing one.

      I am a huge fan of diesel heat. That might be the best solution for the OP, but with the cost of electricity as low as it is in his location, electric is financially a contender.

      I would not go with propane. certainly not with the little portable units. without even delving into the safety aspects, those little bottles of propane are probably one of the most expensive sources of energy (in BTU's) you can find.

      KEVIN SANDERS
      4788 LISAS WAY - SEWARD ALASKA
      where are we right now​​​​​​???​

      https://share.findmespot.com/shared/...j23OquWOj2N3Xe

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        #18
        "ksanders" post=781809 wrote:
        Portland Oregon has a electricity cost of 8.45 cents per KWH

        I'd be willing to bet that is within spitting distance of the cost of diesel as a heat source. (We can go over the math again if anybody wants to )

        If I were a liveaboard in Portland I'd be seriously considering electric for my heating needs.

        This might require an additional power inlet to the boat. It might require getting from the marina an additional power feed or upgrading the existing one.

        I am a huge fan of diesel heat. That might be the best solution for the OP, but with the cost of electricity as low as it is in his location, electric is financially a contender.

        I would not go with propane. certainly not with the little portable units. without even delving into the safety aspects, those little bottles of propane are probably one of the most expensive sources of energy (in BTU's) you can find.
        The problem with electric is you run out of capacity on your boat. We can go over the math again. There is nothing unsafe about propane Kevin, otherwise why would it be installed on so many boats.

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          #19
          We live aboard in Portland on our 3988. Last winter with electric heat only we were popping breakers all the time. Running two reverse heat units and one of those inferred heaters from home depot. Burned up a shore power cord. Really had to learn to manage the loads. Last spring had a hydronic diesel furnace installed. Best heat ever. But with the really cold temps it burns through the fuel. I would say really about the same price between the two. We have learned to run the reverse heat during the days and run the furnace in the evening for a more consistent heat.

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            #20
            "ksanders" post=781364 wrote:
            Diesel is generally the preferred heat source, due to its reliability and its low cost per BTU of heat output due to its low cost per BTU output.
            Diesel = heating oil. It's the same stuff. They just add a pink dye to heating oil so they can catch you if you use it in a diesel engine (it's cheaper because it doesn't have transportation fuel taxes added).

            "Mr. Darcy" post=781528 wrote:
            According to what I studied in second year physics, electric heat is as close to one hundred percent efficient as can be.
            For local heat production, all heat sources are 100% efficient. When you talk about engine efficiency, you're talking about the fraction of chemical energy converted to mechanical energy. The remainder is lost as... heat. So if your intent is to produce heat, all methods of heating (locally) are 100% efficient. Diesel (fuel oil), wood, gas, coal - all are 100% efficient at producing heat.

            The problem with electric heat is that it's not produced locally. Using coal as an example, modern coal plants are about 40% efficient. So they burn the coal, and 40% of the energy is converted into electricity. 60% of it is converted into heat, but that heat is at the power plant, not in your house or boat, so is wasted. As a result, electric heat ends up being the most expensive form of heating unless the area you live in has extremely low electricity prices (around 5 cents/kWh).

            It's actually possible to exceed 100% efficiency by use of a heat pump. Unlike a heater, a heat pump doesn't produce heat. It moves heat from outside to inside (basically an air conditioner working in reverse). With the right temperature conditions, it's possible to move heat inside using less energy than that heat contains, technically giving it over 100% efficiency. But heat pumps are most effective when the outside air/water temperature is around 50-60 F. Below that and there isn't enough heat outside to effectively pump it inside. OP lists 20 F conditions. At those temperatures, heat pumps would just turn on a heating element turning it into an electric heater.

            Generally, excluding heat pumps, natural gas tends to be cheapest, followed closely by propane. Then coal (very dirty - avoid), then oil (varies with the price of a barrel of oil), then electric. Wood is a wild card, varying with the availability of wood in your area.
            1994 2556, 350 MAG MPI Horizon, Bravo 2

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              #21
              I agree with the others. 30 amp service isn't enough to keep the boat comfy and run anything else. Our 4788 has four factory installed electric heaters. I never run more than three at a time for load sharing.

              My experience is around 32F. I cannot keep the salon warm enough running only the salon and companionway electrics. The hydronic diesel furnace heats the entire boat up quickly and has three zones. These furnaces are very small and deliver a lot of heat, ours is 45,000 BTU. I know that others ave installed a separate diesel tank on gas boats, I recommend considering a diesel system zoned to keep your entire boat warm.
              Partner in a 1999 4788

              Seattle, WA

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                #22
                Folks in Missouri where it gets down to 0 use 220 volt electric heaters. They have a 220 volt recepticle installed at the peddistal and run a properly size cord to run the heater. Apparently the 220 volt heaters are more economical to operate.
                Hino W06
                St. Louis, MO
                ”It’s A Wonderful Life”

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                  #23
                  It's all a matter of how much electrical power is available at the pedestal and how the boat is wired: P (watts) = I (amps) x V (volts). Here is the theoretical maximum power that can be used on various boat electrical configurations. I say theoretical because often the voltage is a bit less than the nominal, for a number of reasons. Keep in mind that not all that power may be available to heat the boat. Some of it may be used for other electrical loads.

                  30A service at 120 VAC: 3,600 Watts

                  50A service at 120 VAC: 6,000 Watts

                  60A service at 120 VAC: 7,200 Watts (this is a boat with dual 30A inlets, each connected to a separate 30A source)

                  50A service at 240 VAC: 12,000 Watts
                  1999 3788, Cummins 270 "Freedom"
                  2013 Boston Whaler 130 SS
                  Anacortes, WA

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