Redlon & Johnson helps keep a lot of people cozy during those long New England winters. The company, a wholesale distributor to the construction industry, offers plumbing, heating, air conditioning, and water systems, as well as pipes, valves, fittings, and supplies. Redlon & Johnson operates about 15 locations and showrooms in Maine, Maryland, New Hampshire, and Pennsylvania that sell exclusively to professional contractors. The company traces its roots to Redlon's Supply, started in 1887, and Johnson Supply, formed in 1928; the two companies merged in 1984.