By replacing only the slipcover and not the entire sofa you are helping save the environment. In addition for every slipcover sold $10 will be donated National Resource Defense Council. I took some information about NRDC from their website:

"NRDC is the nation's most effective environmental action organization. We use law, science and the support of 1.2 million members and online activists to protect the planet's wildlife and wild places and to ensure a safe and healthy environment for all living things.

Worth Magazine has named NRDC one of America's 100 best charities, and Charity Navigator has given NRDC four stars (out of a possible four)."