I've had my system in for a year now, and realize the importance of monitoring it. I plan to go with the WEL, based on the reading I've done in this forum. There is data that I'd like to collect to help me find out what the system is costing me to operate. My question is, for the pros, what would you recommend I monitor to help determine what may need to be repaired/replaced/adjusted? My system is a 4 ton ClimateMaster 27 Tranquility split, 2 stage with aux heat strip, closed loop with 4 200' grouted bore holes, water to air, 50 gallon electric HWH with 50 gallon buffer, DSH. I've already planned on monitoring EAT, LAT, EWT, LWT, compressor stages, aux heat run time, HWH run time, and HWH and buffer tank temps. I'm contemplating if I should also record the refrigerant temps.