Is there a limit to how cool a home air conditioning unit will cool?

Answer 1

yes, I'm sure there is. You can run a home a/c unit at any temperature you want, with an understanding of the parameters. They are not designed for a freezer application, but with defrost heaters added, they will provide rated capacity. The thermostat they come fitted with has a low end setting that is too high for a game locker application. Keep in mind that as the temp. difference between the outside and inside increases, so does the capacity needed to make it function. Picture a unit that will cool a 1000 square foot room. The unit works fine for a/c. The same unit on a meat locker is only good for about an 8X10 cooler maintaining 30-40 deg.f. In this application you have installed a thermostat that will allow for operation at 38-40 deg.f. The next thing you need to add is some type of defrost means as when the box is approaching 38 degrees, the evaporator temperature is approaching 20 and ice has formed on it. A simple 120 volt timer in series with the compressor will hold the compressor off, while the fan motor runs melting the ice. Understand also, that as the outside air temp drops, so does the evaporator temp. If the system is to function below 60-65 deg.f. you need to add controls to fake it out into thinking it is warmer. This could be as simple as a simple louver setup to as elaborate as a box fan outside on a thermostat. Some I have seen are just a box on the outside with a door that the owner opens in the summer and closes in winter. If it gets real cold you might need a light bulb too.