Let’s start off by talking about freon, what it is, and why your system needs it. There seems to be many misconceptions that homeowners have about freon. Freon is not like gas to your car, or some kind of fuel the air conditioning system uses. All Air Conditioning units are completely sealed closed loop systems, they are not designed to leak, ever. Just saying that clears up 99% of misconceptions about it. Freon is the refrigerant in your air conditioning system that transfers heat from the air in your house, and removes it to the outdoors. It is pumped by your compressor in a constant loop, from your condenser (which houses the compressor) to your evaporator coil (usually in your attic, or wherever the furnace/Air handler is located in your home) and back again. Round and round it goes, pulling the heat out of the air as it gets pushed across the fins of the evaporator coil (kind of looks like a radiator).
When people say they need a freon fill, the first thing that pops into every technicians mind is “where is it leaking from.” the answer to that question is often, from the evaporator section of the air conditioning system. The Evaporator coil is where the heat transfer happens, as warm air hits a cold coil, it forms condensation. This humid, wet environment acts on the metals of that coil, to oxidize and form rust and break those alloys down over time. Often this results in microfractures, and small, diffuse pinhole leaks. These leaks can range from big to small. If you’ve ever had your unit topped off only to find the next day it was blowing warm air again, then you have a large leak. If your unit only takes a pound or two of refrigerant, but last you the whole summer season, chances are you have a small leak.
Common signs and symptoms of a freon leak can be, warm, or less cool air blowing from your vents. Units taking longer to reach temperature that the thermostat is calling for, or not reaching temperature at all. Ice forming in your coil, and traveling down the line set to your compressor, enveloping it in a shroud of ice (kind of weird to see on a 95 degree day). When in doubt some of the things to check first your air filters, make sure they’re clean. If it’s been a month or longer, go ahead and change them. check the outside unit for ice on the line set or around the compressor. If it’s there, shut off the unit and seek professional help. If it isn’t, feel the air temperature coming off the unit, it should be hotter than the outside air temperature, if it is great! but that means your problem may lie elsewhere.
Running a unit that is low on freon is the equivalent to running your car while it’s low on coolant or oil. It’s not going to end well, and even if it’s providing some relieve from the heat you could do more damage to the unit.