Because most homeowners do not know a whole lot about their home units, and so they put all their trust in the technicians. When purchasing a unit, you need to go with your technician so they can advise on the best unit for your home or business. I had decided to visit the local business to get more information on the best unit. The retailer suggested a unit that I thought was very costly but he enticed me saying that he would also provide technicians who would fit the unit. Because of the promise of a technician, I decided to purchase the hybrid HVAC system for my one-bedroom home. The air conditioning supplier also suggested I purchase some of the cooling products that he advised had specialized cooling technology that would be ideal for my home. When the technicians finally came to execute the a/c set up, I noticed that they kept referring to their phones for directions on how to install the unit. The retailer had accompanied then and was advising me on the importance of regular home service for the unit. I expected the air quality to improve as soon as the air purifier was switched on but apart from the rumbling, nothing changed. After a week of calling the retailer to complain about the whole home air purification unit was not working, I opted to use more money to get another retailer and technicians from a reputable company who came and installed an AC filter and schooled me on the planned a/c care program plus the different HVAC brands such as the mini split air conditioner which would have been ideal for my home. I had an unpleasant heating and cooling service experience but one professional changed my view of retailers.