First Supply 6800 Gisholt Drive Madison WI 53713 is a wholesale supply house providing industrial customers and building contractors with an extensive line of products and services in the plumbing HVAC builder waterworks pump/well & septic industrial and municipal markets. Areas Served: First Supply operates 28 supply houses throughout the upper Midwest. What Brands Does First Supply Sell? First Supply carries name brand products from A.O. Smith Amtrol Aprilaire Armaflex Armstrong Asco Bacharach Beckett Bell & Gossett Braeburn Calefi Climatemaster Comfortmaker Cozy Daikin Danfoss Diversitech Ducane Emerson EMI Fantech GE Grundfos Hart & Cooley Honeywell Johnson Controls Little Giant Nu-Calgon Parker Reznor Ritchie Robinair Taco Tjerland and many other HVAC supplies.