its double glazed on the visible sides and insulated on the back with polystyrene panels.If I breathe real hard on the glass I can just about get it to mist up.
I've got an idea. Actually more of a concept. I wonder if there's a reliable way to build a small holding tank and bury it underground. It would be like a sump, but only to store water. You'd need a way to thermostatically control the pump for it. Anyone see what I'm getting at? I can't imagine this not being theoretically possible. The temperature should stay rather cool year round, and it won't freeze in FL.
I wonder if you could constantly pump the cold water though a copper pipe wrapped around a vinyl tube or something. Have tank water pumped through that tube rigged to a thermostat somehow. That way the cold water is always pumping, not into the tank, and your tank water only goes through when needed. It's kinda the opposite of a chiller. Instead of the water always flowing and the chiller running when needed, you have the "chiller" running all the time, and the water running only as needed. If you think about it you're always running a pump with either method so no extra energy there, but the other is only running as needed. A pump has to use far less energy then a chiller, even though it would need to run more.