I haven't kept up with solid state switches but assuming they drop 0.4 Vdc and you're pulling 4 amps to your refrigerator
that means the switch is turning 1.6 watts into heat. Notice the solid state switches look like big heat sinks. It'll be winter soon so the extra heat might be a plus. :-)
If you're really hurting for energy you may want to look at the equivalent in relay technology. That's the way I'd go unless it turns out they have a reliability
problem with contact pitting.
Anyone with some experience with these technologies out there?