Abstract: A modular filtration system for cleaning HVAC ductwork includes first and second modular assemblies containing a plurality of filters. The modules can be easily transported into a site and connected to one another and to the ductwork. The system includes a plurality of wheels and external assembly protruding from the housing to assist in wheeling the housing up and down stairs.

Abstract: A method is disclosed for cleaning HVAC ductwork, including the steps of transporting first and second modular filter assemblies to a site, connecting them in sealed fluid communication with one another and to the ductwork, drawing fluid through the filtration system from the HVAC ductwork, exhausting filtered fluid from the filtration system and tilting the housing so that any stairs present at the site bear against a bearing surface of an external conveyance assembly as the modules are transported up and down stairs.

Abstract: A portable vacuum and air filtration unit, comprising: a plurality of separately transportable modules and a means for locking the modules together during use, an air inlet located in one of the modules, a debris screen and a means for receiving debris stopped by the screen located in one of the modules, an electrostatic filter located in one of the modules of some embodiments of the invention, a bag filter assembly located in one of the modules, a HEPA filter assembly located in one of the modules, and a means for drawing a substantial volume of air through the inlet, screen, electrostatic filter, bag filter assembly and HEPA filter assembly.