It uses a small Danfoss compressor. With a well insulated 3 cu. ft. icebox it seems to be running for 3 to 6 minutes every 1/2 hour to an hour pulling about 6 amps. I'm guessing it's using in the neighborhood of 20 amp hours a day. Wish I could be more precise but those are my casual observations while living aboard for the past 3 weeks.