Why does my La Presa home's AC run constantly but still not cool the house?
That's a strong sign of both undersized original equipment and leaking ductwork, a common combination on 1970s-80s La Presa tract homes. We run a duct leakage test and Manual J load calculation before quoting replacement, since sizing the new equipment without addressing 25 to 40 percent duct air loss just repeats the same comfort problem with newer equipment.