After reading posts in this group, and with my own experience, I am wondering if there are design problems with HE furnaces. One problem is severe radio interference (both AC and battery radios, inside and outside the house) which at least one manufacturer has to some degree corrected by supplying a special kit for the inducer motor. Another problem involves venting, with animals and insects able to block outside vents which have no protection against entry. Still another issue is increased use of electricity (i.e. from coal fired generators which produce more carbon emissions than gas and may actually worsen the end environmental effect).