Guide to Choosing Condensing Units

Condensing units; Air cooled (AV, AH, Capri, Paris), Water cooled (W) or Keel cooled (K).

Air cooling is the least efficient cooling medium compared to water, but is cheaper to buy & easier to install. To achieved maximum efficiency, they need to have the coolest possible air forced by the fan across the condenser, & the heated air expelled away into a different area. Water is a far denser medium than air & typically stays at a lower temperature than the air inside the boat or locker. It is generally accepted that water cooling is 20% - 30% more efficient than air cooling, but it involves installing a pump, which adds approx. 1amp (at 12v) to the total current draw as well as adding the uncertainty of a clogged strainer or pump failure. Using a Keel Cooler is the logical step up from a pump-fed water cooled system, as now the condenser is outside the boat, & the only moving part of the system is the compressor. This makes for the quietest, most reliable, & most efficient system of all, although it requires that the boat be hauled to install the keel cooler. The keel cooler is also available with sacrificial zincs, which is not necessary in normal applications, but may be required if the boat has a “floating ground” system. It is a requirement of any installation that the keel cooler be connected to the battery negative as a safety measure, & this normally will connect the keel cooler to the bonding system & also the shaft or hull zinc which will protect the keel cooler.