Air Conditioning Aboard Without a Genset?

As we glide into the hot, humid and hazy days of summer, the thought of putting air conditioning aboard our boat comes up in conversation more and more frequently. Wouldn’t it be nice to have dry cool sheets to sleep on. Wouldn’t it be great if we didn’t have to wipe down bulkheads and cabinets with vinegar to ward off mildew? The problem is, we rarely go into marinas while cruising so we can’t plug in to shore power. And, we don’t have, don’t need and don’t want a genset. What we do have is a high-output alternator, a medium size-array of solar panels and a 400-amp-hour house battery bank. Is there a 12-volt air conditioning unit that will run off this power supply?
     To get an answer, I turned to our friends Rob and Gretchen who own and run Coastal Climate Control in Maryland whose website is a treasure trove of sensible advice on all things to do with energy, heating, cooling and refrigeration on boats. I found on their site a great blog post on just the question we have about 12-volt AC. It turns out that there are 12-volt units that can run off our system. Great. But, it also turns out that they are quite expensive and not all that energy efficient. But, according to Rob’s blog, you can run a small, less expensive 115-volt AC unit through a 1000-watt inverter (which we have) and that will actually cool our boat and not completely deplete the battery bank. Umm. Food for thought as we get out the vinegar spritzer to wipe down the head cabinets. 
    Read Rob’s blog here.