The most important thing to learn if you buy a superior brand air conditioning unit such as a Carrier is how to properly detail it.
Use a very mild soap for its wash and use a soft bristle toothbrush to clean in between the air intake vents. Pay special attention to the base of the unit as this is where dirt tends to pile up. For drying use a Chamois cloth- NEVER use a regular towel or you'll get lint from the towel inside the unit.
For waxing I hand apply Mothers' car wax, being careful to work the wax in a circular motion- NEVER straight back and forth. It's OK to use a machine buffer, but for the air intakes you'll have to wrap a cloth around the handle of your toothbrush to properly remove the wax.
For all the hoses and connectors I use STP's "Son Of A Gun" to maintain that like-new appearance. NEVER use Armor-All, as that will cause the hoses to eventually crack.
If you follow these instructions your air conditioning unit will maintain its resale value and be the envy of your neighbors- kinda like having the only working porch light during a power outtage.
I have a matching bra on my air conditioner to guard against rocks, golf balls and bird droppings. Before I reapply the bra I vacuum the inside to prevent any dirt from scratching the finish of my air conditioner.
If any of you need help detailing your air conditioners bring them by my place and I'll put the products on for you, but you have to take them off.
Some day I'd like to start an air conditioning detail business as a side job. I enjoy the work, and the way people look at me and my air conditioner is extremely satisfying.