Our cabinet is in a coastal area, and early in the morning there is condensation inside the door. How do we protect the computer inside?

Condensation forms when surfaces inside the cabinet are colder than the dew point of the air, typically at night and early morning. Water plus coastal salt corrodes component leads very quickly. Measures in order of effectiveness: 1. Keep the cabinet a few degrees warmer than ambient with a cabinet heater controlled by a hygrostat, usually set to switch on when internal humidity exceeds about 65–70%. This is the most effective and inexpensive fix. 2. Seal the cabinet: sound door gaskets, cable glands on every entry, and a breather vent with a waterproof membrane to equalise pressure without drawing in moisture. 3. Choose a sealed fanless machine with conformal-coated boards if the vendor offers that option. 4. Keep the machine running rather than switching it off overnight: a running machine generates its own heat and is less prone to condensation. Avoid fitting fans that draw outside air into a coastal cabinet without suitable filtering, as they pull in more salt-laden moisture.