Given comparable COP values why not oversize my system? I have 5 ton water to air open loop system running on an efficient VFD driven well pump. Combined COP values of 4 (heating) to 6.7 (cooling). I love never having to run emergency backup, and being able to turn house temps down at night and bring them back up quickly in morning. Also with proper duct isolation and soundproofing in utility room it is silent. So other than slightly higher initial costs (I designed and installed system myself), what benefits would I gain from a smaller, more appropriate size system? Is there an initial waste of electricity getting the pump started and up to pressure, how significant?