DE45 Eolian Gets a Heat Pump Part 1: by Bob of Eolian

I had always thought heat pumps were the perfect answer for heating/cooling on a boat, but never considered one due to their cost. When I saw a two-year old one on craigslist for less than 1/4 the retail cost, I jumped without hesitation.

(An aside to those who do not know how a heat pump works: A heat pump is almost exactly like an air conditioner, but with the addition of solenoid valves which allow reversal of the freon flow. Did you ever notice that a running window air conditioner blows hot air outside? That is the heat which was removed from the cooler inside. If you were to physically turn the unit around in the window, it would become a heater. The solenoid valves allow this reversal of function without having to physically move the unit. And yes, the heat pump is also an air conditioner. One more thing: on a marine heat pump, the heat source/sink is not the outside air, but is instead the water. In Puget Sound, the water temperature ranges from about 55 degrees in the summer to about 48 degrees in the winter, so it is perfect for this.)

Here on the boat, we live on 30 amps. That is, the total amount of power available to us is a little less than what you can get from 2 household circuits. This requires us to be conscious of our electrical usage. With the current price of diesel, it is cheaper to heat the boat with electricity than using diesel in our diesel heater. To do this, we have used 3 space heaters (forward cabin, main saloon, aft head), each set on a 500 watt setting. Thus we were heating with 15 amps, leaving another 15 amps to run the water heater, refrigerator, espresso machine, […]