In October 2014, I bought a Trane XV18 outdoor unit model #4TWV8036 from a popular installer in Northern Virginia. This unit was to replace a Ruud single stage 11 SEER unit located just outside of my master bedroom wall. The installer led me to believe that decibel level output by this new variable speed unit would be considerably less than what we were used to. Trane advertises the unit to run at 72 decibels (47 degree ambient temperature). As soon as winter hit and we cranked on the heat, I knew a mistake had been made, and I was in for a ride. Long story short, the unit was running at just under 90 decibels and the variable speed compressor put out a searing noise that would not let me sleep at night. The installer agreed to decibel test the unit and found the same outcome. An insulation blanket was placed over the compressor to decrease the noise by 5 decibels. The installer and a representative from Trane came to my home to tell me that my unit was running according to specs. I was told that other customers were having similar issues with XV18 noise output and that Trane was putting out a software "patch" that might help. It did not. The installer also offered to change my unit's compressor settings to decrease noise output, but I told the installer that I paid to have the unit run at maximum efficiency. At this point, many emails had gone back and forth between me, the installer, and the Trane rep over the course of 5 months. Since the high speed compressor was the real issue, I even asked to have my XV traded out for a two stage XL. However, Trane would refuse to reimburse me the difference between the two units. So, I was stuck with a noisy, variable speed unit. Finally, the installer agreed to move the unit to a farther point away from our bedroom at no additional cost. We are now in the AC season, and I must say that the unit is true to form during the summer months. Noise levels are as advertised when the unit is in AC mode. In conclusion, my advice to-date is to avoid placing the XV18 anywhere close to living space that requires low levels of noise. This unit offers high levels of noise output at high pitch when in heat mode at 50% or more compressor speed.