Duct Works Air Duct & Dryer Vent Cleaning (Koster Services, LLC) is a locally owned and operated company based in Grand Rapids, Michigan. We provide residential and commercial air duct, dryer vent, and carpet cleaning throughout Michigan. We pride ourselves on quality work at fair prices. We are an “A” Rated Company with the Better Business Bureau and Angie’s List. Duct Works received the “Super Service Award” from Angie’s List for 2012 and 2013.