The HVACR business is designed to be as opaque as possible to the consumer. The consumer is forced by the industry, laws and environmental regulators (for good

The HVACR business is designed to be as opaque as possible to the consumer. The consumer is forced by the industry, laws and environmental regulators (for good reasons sometimes) to use licensed service providers. These providers, in order to protect their jobs will refuse to provide any technical details on how to fix things. Further, as these systems continue to get more and more complex due to regulations and efficiency requirements it has become increasingly harder for service providers to debug the issue. So they instead send out cheap labor to peddle replacement over repairing, hoping the customer will agree to a new system. Combine that with the service providers being able to offer clever financing, homeowners simply bend over. A new system can be anywhere between 6k-12k per unit with some houses in the U.S. requiring 2+ units. I've dabbled a few times in fixing my own HVAC system. Procuring parts or entire systems are usually not possible for the individual homeowner. Businesses selling these things simply refuse to sell to someone without a license. You could certainly invest in some time and money to get your own license. At my local community college I can get an EPA license to handle refrigerant and some other HVAC licenses. Of course to handle refrigerant you will also need a few hundred dollars in equipment like a Yellow Jacket and a pump. The UI/UX of HVACR controllers is also designed to limit the amount of information a homeowner can access. For example, Carrier is a large manufacturer of heat pump systems. They have secret hidden menus in their thermostats that only technicians can access. They have a mobile app that allows one to get critical logging information about the system (analogous to the ODB2 port on a car) this requires an account that one can only get if they have a state license. Also Carrier, Trane, Goodman, etc. are like "systems integrators". The compressor is typically made by a third party. But it is tribal knowledge as to who made the compressor and where to get replacement parts. Carrier et. al. will not tell you. And if you do find the compressor manufacturer good luck getting them to talk to you. Often getting replacement parts requires hunting through eBay and other marketplaces.