Manufacturers, wholesalers, contractors, and even electrical
utilities rigorously promoted the concept, and a new market was
launched. Shortly thereafter, however, came the complaints,
particularly in the Southeast, of an odor originating from the
much-endorsed units. This foul smell sent manufacturers,
wholesalers, and service entities scrambling. The odor was
characterized in many ways, but the most vivid description was
“like someone’s gym socks found their way into my a/c unit.” The
term “Dirty Sock Syndrome” was born, to the chagrin of the
industry, and soon became the unofficial name for this heat pump
phenomenon. The only known remedies at the time were to clean or
replace the coil, use drain pan treatments, or in extreme cases,
replace the entire unit — and even that didn’t always solve the
problem. Generally speaking, however, frequent cleanings with
bleach did temporarily reduce the odor to acceptable levels. In
the late 1980s and early 90s, indoor air quality became a
nationally recognized issue; t