I am a generally handy guy, but don't know a lot about HVAC. I live in Kentucky, so summer temps are about 85-90F, winter gets down to 10-15F at night. I have a 13 year old heat pump that I've been having a few problems with. Last winter it froze up pretty badly and I had the 'board' replaced. This was right as the end of winter, and the compressor was lounder then normal all summer. Then I was out of town for several weeks this winter and apparently it froze up completely (had about 5" of ice on the outside when I got home). I let it thaw (by going to emergency heat and catching some warm weather) and had a guy come look at it. It had a bad defrost sensor, which he replaced. The sensor he put on the output line was getting up to about 140 when he tested it after this, coolant level was fine according to him. The compressor is now VERY loud. He says this was caused by liquid freon getting in it while it was frozen up. Is my best option here basically to replace the outside unit? The outside and inside? Or just the compressor?