My system, a Climate Master 27, was installed in March of 2011 and has operated with no maintenance other than clearing the condensate drain trap. I was curious to know exactly how much energy it was consuming so I installed a watt meter (standard electric meter just before the power enters the unit junction box) and started tracking my power consumption. For the two year period that includes all of 2016 and 2017 my system used an average of 373.75 KWH per month. (The average cost per kwh in Raleigh is approximately .10). The house is 2,600 sq. ft.; 1,800 on the first floor and 800 on the second floor and was built in 1990. The insulation values exceed the current building code minimum requirements (I'm a builder). I'm not up to date on the latest models but it would be great if power consumption were displayed through the thermostat or a wirerlesss computer app.