A mini-split air conditioner should be one of the least noisy temperature control systems, but mine started to sound like an old mill. When I searched for a new air conditioning and heating unit, the cooling expert suggested this ductless heat pump, and I immediately fell in love with the idea. It was just the thing I needed to solve my indoor air quality issues. I had a furnace at the time, and I realized that I was losing heat through the HVAC duct even when I constantly carried out duct sealing. (The new contractor suggested that I have a zone control system that would enable me to control the temperature settings in different regions. If done correctly, I would be able to reduce the amount of energy I used for either cooling or heating the home. The other thing the cooling specialist told me to keep in mind was that the unit required more ac care than my previous system, and therefore instead of annual air conditioning tune-up, it would have to be done twice a year. It would be a small price to pay for indoor comfort. However, I did not follow his advice, and I neglected the unit, which was why it had become so noisy. I called the HVAC business and told them everything wrong I had noted with the ductless system. I also ordered a new thermostat because even without the input of a professional, I knew that age had taken its toll on it. The tech repaired and serviced the system, and it stopped being noisy. The cost for the repair far surpassed what I was trying to save in avoiding maintenance.