[ClockworkC5]

chances are the leak is in a joint, or in the coil. easy to find. the copper that runs from your air handler (inside) to the compressor (outside) is typically a single piece of spooled copper. this means that a leak somewhere burried in the house is relatively rare. check the fittings around each unit. the last house i was in, the leaks where in the test ports. these are located just outside the compressor and have caps on them. alot of times these are not properly tightened and the valve eventually slowly leaks. any service tech can come out, locate the leak, remedy and refill your system for less then $100. your best bet is to find a small, one man residential company. this way your not paying for the overhead of a big office, advertising, ect. i found a guy that i have used a few times, and did a great job. same problem your describing cost $80. come out, locate, fix and refill system. check online for local listings. the guy ive used in the past name is bob. 813-317-8628. letme know if theres anything else i can help you with.