Dennis Supply Company was founded in 1935 in Sioux City, Iowa by Carter W. and Ebba R. Dennis. Mr. Dennis had previously been in the refrigeration service business for some time. In 1975, Carter R. Dennis joined the business with his father and Jim Stewart. Additional branches are located in Council Bluffs, Iowa, Rapid City and Sioux Falls, South Dakota, Lincoln, Omaha, Grand Island, and Scottsbluff, Nebraska, and Casper, Wyoming. The territory covers the western third of Iowa, the southwest corner of Minnesota, all of South Dakota, Nebraska and Wyoming. In addition to Dennis Supply, Wayne Dennis Supply Company became part of the Dennis Supply corporate family in 2005. They have branches in Des Moines, Urbandale, Ames and Waterloo, Iowa. The addition of this long time company (1937) has added strength in territory and service throughout a larger portion of Iowa.

The original emphasis of both companies was refrigeration and the Dennis Supply had been a member of A.R.W. (Air Conditioning & Refrigeration Wholesalers Association) for many years. The company had grown significantly in the heating and air conditioning industry and was also a member of NHRAW (North American Heating, Refrigeration & Air conditioning Wholesalers Association). These two organizations have now been joined together to form HARDI (Heating, Air Conditioning and Refrigeration Distributors International).

Dennis Supply Company is known throughout its territory and the industry for its high standards. Not only for having exceptional inventories, our personnel list is long term and knowledgable. Our customer base knows there are nine locations of inventory in Dennis Supply and four more in Wayne Dennis Supply to work with, as well as our association with other distributors that adds hundreds of other branches of inventory to cover emergencies. This strength in numbers not only adds inventory coverage, but allows Dennis Supply to combine purchasing power with other quality companies. This gives the customer competitive prices combined with local ownership to make for strong service with a personal touch.

Dennis Supply Company is a closely held corporation who has had only three presidents in its history. Carter W. Dennis, James B. Stewart, and the current president Carter R. Dennis. They were pictured on the front cover of Distributor magazine after Dennis Supply was picked as the 1988 Distinguished Distributor. All of this allows Dennis Supply Company to complete its mission of providing the highest level of service in selling quality products at a competitive price.