Hi Thor,
Last season ( our first with Soave ) her fridge failed to maintain it's target temps on hot days. I did a needs analysis and searched for options.
In areas that are very hot ( like Caribbean ) a water cooled system makes sense, if you are comfortable with the complexity of the added plumbing and hull penetration. In more moderate climates, air cooled systems look more attractive. I noticed that Canadian boats often locate their fridge compressor/ condenser in the cabin while boats further north normally put it aft in the engine compartment.
Soave's condenser is in her engine compartment, on hot days the closed compartment can sometimes reach 110ºF.
To make a very long story short, Soave is a 1980's vintage boat with a retrofitted 2010's Isotherm compressor. The system "works" but it is not even close to the efficiency of present day systems. Which have the following advantages :
- Inverter compressors which have the ability to adapt to the cooling load. No more cycling on an off, the compressor can run at a very low and efficient level until more cooling is needed. Midea has a very nice implementation of this in some of their window AC units. In time this will find it's way to marine refrigeration.
- Well insulated, properly sealed compartments. The most effective way to reduce cooling load.
- Remote monitoring. Surprisingly handy to provide early detection of problems or simple stuff like a door left open.
In the end I bought a $75 set of refrigeration gauges and recharged my oldish Isotherm system. It's just completing it's second season since the recharge. The couplings I tightened before the recharge were probably leaking.
I'm hoping the next generation of marine fridges will catch-up. If Soave's fridge dies too soon, I'll probably look at RV refrigeration equipment as an option. There are some very nice self-contained units that can be powered by either A/C or DC power sources. Dometic CFX2 is a highly regarded portable.
For now we'll keep nursing our Isotherm.
My intuition is that for a northern boat like your's, an air cooled condenser will be the favored option. You may benefit from placing it in the cabin to mitigate humidity.
Good luck in your search if you find an option the works for you, please share.
Robs/v SOAVE
NS33 #009
Cedar Point YC
Westport, CT
On Sunday, September 21, 2025 at 1:38:48 PM UTC-4 Thor Powell, Nonsuch 26, Victoria BC wrote: