Plumb Supply Company 207 Iowa Avenue East Marshalltown IA 50158 was founded in 1946 as a plumbing supply company adding in HVAC supplies in 1956. Originally with only one branch location Plumb Supply Company now operates 18 HVAC supply Houses. AREAS SERVED: Plumb Supply Company operates 18 HVAC Supply houses throughout Iowa. BRANDS CARRIED: Plumb Supply Company carries name brand HVAC supplies from Aspen Ruud Bell & Gossett Hoffman Honeywell Taco Tekmar Atco Fujitsu GE Reznor Glasfoss Tjerland First Company Watts Grundfos and many others.