In an effort to grow their business, many residential air duct cleaning contractors look to the opportunities the commercial market offers. This is a natural progression, as residential contractors first add light commercial projects (one story office strips, etc.) and then add multi-story commercial projects (office buildings, schools, hospitals, etc). There are differences, however, that the residential contractor needs to be aware of so they can plan and be prepare for this transition. These differences include: Work Time: Residential projects are typically done during the daytime while most commercial products occur during the 2nd shift (4:00pm to midnight). HVAC Systems: Residential heating, ventilating and air conditioning systems (HVAC) systems are relatively simple to understand and are modest in size while commercial HVAC systems are larger and more complex. You'll deal with many more components like in-line heating coils, VAV boxes, fire dampers, turning vanes, internal ...