Furnace Sizing Professionalism

Now that the fall season has rolled around, the cooler temperatures are a good reminder to brush up on all things related to furnaces. This article by Gord Cooke, which was originally published in Mechanical Business, March  2017, outlines how “we as an industry, particularly contractors, salespeople and designers, need to recalibrate the way we think about furnace sizing.”

One of the people I work with was recently shopping around for a replacement furnace in his older home and had a local HVAC contractor come to his house to quote the job. After walking around with a tape measure and calculator for 5 minutes the salesman announced that the house would require at least a 60,000 btu unit. He acknowledged that a 50,000 BTU/hr unit, like the one that was being replaced, would probably do the trick, but seeing as the contractors brand of choice only came only in 40, 60 or 80 increments, he defaulted up to 60,000 BTU/hr. My colleague raised concerns about this size recommendation, as the 50,000 BTU/hr mid-efficiency unit being replaced had always seemed to be short-cycling. The salesman assured him that he would be ‘rolling the dice’ going with a smaller unit, reassuring him that he’d been sizing and selling furnaces this way for almost 20 years… etc., etc.read more