When shopping among different brands and models, there are a few things to consider that will help narrow your decision.

Bigger is not always better

You want a boat refrigerator with the capacity to hold all of your perishables, but you don't want to waste space, money, or energy getting a unit that is too large. When looking at a marine refrigerator's size, you will need to consider outside dimensions when judging the fit into your galley and the inside dimensions when determining capacity. The insulation will create a substantial difference between the two measurements.

Your size options will probably be limited by the interior space on your boat. If you have a small craft you won't have the room, or likely the need, for a large refrigerator. Measure the area where the unit is going to be installed so you don't waste time looking at fridges that are too large.

Once you have a maximum outside measurement, you need to consider capacity. If you use your boat for short trips around the bay you probably won't need more than a 15- or 20-liter unit. A recreational fishing trip might need a larger marine refrigerator to store the catch on the trip back. A large vessel that is used for multi-day trips will need even more storage as you will be depending on this food for survival rather than for snacking.

Temperature and power considerations

Do you need a freezer or will a simple refrigerator suffice? Many boat refrigerators can be fitted with a lower-temperature thermostat allowing them to serve as freezers instead. This may be a luxury or a necessity depending on the purpose of the refrigerator. As with size, remember that lower temperature means more power use.

Is your boat's electrical system up to the power demands of the unit? If you will be running your marine refrigerator for long periods when the engine is off then you need to examine your battery capacity. The power demands of refrigerators as well as other high-power items like microwave ovens will require at least one deep cycle battery to keep everything powered.

Is she seaworthy?

Boats require dedicated boat refrigerators. Other small non-marine refrigerators are available and some owners are attracted by the lower price, but these units will actually cost you more in the long run. They don't hold up to the corrosive effects of the marine environment and will require frequent replacement.

Even boat refrigerators are sometimes built of inexpensive materials that don't last. Look for materials such as anodized aluminum that are rustproof or stay away from cheap plastics that will break the first time a wave rocks the boat