Why it matters to you
In humid Greater Houston the evaporator coil does much of the work of keeping indoor air dry, so a dirty, frozen or leaking coil shows up as weak cooling, clammy rooms or water near the indoor unit. When a system is replaced, the indoor coil has to match the new outdoor unit and its refrigerant.
Practical guidance
Change filters on schedule, since a clogged filter is a common cause of a frozen evaporator coil. If you see ice on the coil or refrigerant lines, switch cooling off and run the fan only, then call for service; coil cleaning, leak testing and replacement are technician work.