Join Date: Mar 2006
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Re: Issues with Heating in Annapolis, MD
My understanding of heat pump/ac type units that lack additional resistive heating elements is the most efficent units can only heat or cool approximately 30 degrees from ambient.
So on a 100 degree day, ac is only going to get you down to about 70 degrees. Conversely, if its 20 outside, about 50 is all the "heat" you can expect from a heat pump unit. You are gonna need some alternate means of heating your boat when the temps get below about 35 degrees.
Home heat pump units have a "second stage" to take over when the heat pump alone is not enough, but marine units lack this feature. The second stage is usually electric resistive elements.
s/v Palmetto Moon
1991 Catalina 36