For more than 80 years, K.C. Company, Inc., has provided outstanding value to homeowners in Delaware, Maryland, Northern Virginia and Washington, D.C. Since 1964, K.C. Company has grown to one of the largest independent and locally owned Pella retailers in the country and we’re proud to continue our tradition of quality, value and service. Our unwavering commitment to homeowner satisfaction is summed up perfectly in The Pella Promise: 1) Provide the best quality product for your home and budget; 2) No mess, no guess installation; and 3) total care guarantee.. Replacement Windows & Doors - Wood,Vinyl & Fiberglass.