Champion Windows & Home Exteriors | 10,980 followers on LinkedIn. We design, build, install and guarantee it™ | With over six decades of experience and expertise, Champion Windows and Home Exteriors, a Great Day Improvements brand, is one of the nation’s leading home improvement companies. Champion transforms homes with premium-quality products that are designed, built, installed, and guaranteed by Champion. Every product the company offers – from new windows and sunrooms, to siding and entry doors – is built right here in the USA, backed by industry-leading limited lifetime warranties, and comes recommended by 9 out of 10 recent Champion customers.