This is the second article in a series about big accessories that we often wonder—do I really need that on my boat? Watermakers, generators, and air conditioning are generally things you will have on your want list, but should they be on your “must-have” list?
Keep your cool, man. Here are my thoughts on marine air conditioning and why it’s a must-have on my next boat.
Do You Need an Air Conditioner on a Boat?
When we first went shopping for our liveaboard cruising catamaran, we had several notions about air conditioning. We justified buying a boat without it because doing so enabled us to buy a larger, newer boat than we actually needed at the time.
There’s some overlap between this conversation and how you budget for your boat. I’ll try to keep it focused on why I think an AC is necessary. But it’s important to coordinate some of your wants and needs with your budget. In hindsight, we should’ve found a smaller, better-equipped boat for the same (or less) money.
Some folks go into buying a boat and know from the outset that they need an air conditioner. We were on the fence and figured that we planned to spend time at anchor where we wouldn’t need it (and couldn’t run it without a generator, anyway).
Our broker said you needed air conditioning if you were going to stay at a marina dock, but you didn’t if you were going to stay at anchor. That’s pretty sage advice.
We soon discovered that we spent far more time in a marina than we ever planned. Once we bought the boat, we decided to keep our jobs for an extra year while living aboard. We lived in South Florida, so the first thing we had to figure out was how to arrange a portable air conditioner to cool the boat down—for an entire year.
We went north and spent some time in the boatyard, where that portable air conditioner came in handy again. (A marine air conditioner would not have helped here since we were on land.) The following summer, we decided to take a few months off cruising and get a dock in North Carolina. And guess what we used every day that summer? That portable air conditioner.
All of this might sound like evidence that a portable air conditioner is the way to go. The truth, however, is the opposite. I hated using it. It was loud, and it never did a great job. We could mount it in the salon, but then we didn’t get much in the stateroom. It took up a huge amount of storage space when it wasn’t in use, and it took up a big part of my kitchen counter space when it was in use.
Why didn’t we just install proper air conditioning, you ask? To properly cool our catamaran, we’d have needed at least three units: one for the salon and one for each hull. A marine air conditioner costs about $2,000 for the unit alone, plus at least another $1,000 in miscellaneous parts to make it work (pumps, through-hulls, hose, ducts, wiring, etc.). If you were paying someone to install one in a boat without previous air conditioning work, it would easily cost another $5,000 in labor for a catamaran, which makes the total of adding marine air conditioning somewhere around $24,000. For a monohull with only one unit, it would be around $8,000. So, we bought a $300 portable air conditioner at Lowes and sweated a bit on the hot days.
Upon selling that boat, we knew the next boat must have air conditioning. Even if it didn’t work, replacing the unit would be small compared to the cost of installation and system planning.
Unfortunately, none of the boats we looked at had one, so I put it in myself during our first year. It was a beast of a project, and let me tell you, if you find someone to do the work for the $5,000 I quoted above, you should be very pleased that you got a good deal. Air conditioning is one of the toughest things to put in a boat.
In all of this, I haven’t answered, “Who needs a boat air conditioner?” It’s a personal choice, but ten years of living aboard has proven to me that it is a “must-have” for nearly every boat you might consider living on for any time.
It should have air conditioning if you plan to sleep on a boat at a marina. If you want to be on the hook and want air conditioning, you really should have a built-in generator (probably diesel). If your boat has a built-in generator, you can easily use your air conditioning at anchor. You don’t have to, but it would be very nice for those windless, hot nights. Or the warm nights when it’s raining too much to open the windows. It is technically possible to run air conditioning off large lithium battery banks. This is a very expensive option, but if you’re creating the lithium infrastructure for other things, then it makes sense. However, you’d still need a large on-board generator for cloudy times.
All of that discusses buying a boat, but selling it is also an important consideration. When it comes to cruising boats, most buyers today want air conditioning installed. That means that boats with AC have a higher resale price and are more desirable. In tough markets, it’s very nice to be selling a desirable boat as it will move quicker and demand top dollar.
Boat Air Conditioners 101
Marine AC fundamentally differs from building systems because it uses seawater to cool. It uses a water pump to bring water in through an underwater through-hull, cycles it through the system, and then spits it out above the waterline somewhere. The pump’s output must match what the air conditioning unit requires: more powerful units need more powerful pumps.
There are different styles of air conditioning units, but most are a single combination compressor/evaporator unit that can be mounted under a settee seat or berth. Air is ducted over that unit and out through the boat’s duct system. The system is rated in BTUs (British Thermal Units), with boat units ranging from 6,000 to 18,000. The more BTUs, the more power the unit consumes.
Units sometimes come with reverse-cycle heating, a heat pump that can be used as a heater in the winter. However, this option only works if the seawater temperature is above 40 degrees. As a result, it becomes less useful the farther north you stay during the winter.
Ducting through any boat’s cabinets and bulkheads is a major chore. Ducts are usually between 3 and 5 inches in diameter, meaning you must drill some pretty big holes. Once installed, you’ll probably lose a significant amount of cabinet space.
Proper installation is key in many ways. If the ducts don’t run straight, it can add noise and reduce the flow of cool air. The water pump must be installed correctly so that it does not clog up easily, which would cause the air conditioning to overheat and shut down. The sea strainer needs to be easy to access and clean. The air conditioner will also produce a lot of condensation, which must be ducted away or pumped overboard. If the drain gets blocked, it can flood the compartment, possibly damaging the wood.
What do you think, is air conditioning a must-have item on your boat?
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