A couple of reasons... The young lady, Katherine, who took my call was kind, interested and professional even as I bumbled through my 'problem'. Mahdi, the technician, was equally professional in his service. He called 10 minutes into the 4hr window of appointment. He checked the filter, the outside vent and then proceeded to move forward in his analysis... He located the problem and explained clearly and patiently what he needed to do. He replaced the 'faulty' part and fixed the furnace in about 30 minutes or so. He was very polite! DE Home Services has come a long way in the past couple of years... Keep up the good work. You have two excellent representatives of the corporation's public image...