When does MDF offgas? When the heat is on in the winter or throughout all seasons?

— Rachel Mitchell Rutland, MA

Answered by David Bergman on July 13, 2010

What are the "cleanest" materials for a fresh-air intake duct?

— Brian Trenton, NJ

Answered by Scott Collins on June 17, 2010

What are some of the health benefits of building green?

— jay Roswell, GA

Answered by David Edwards PhD on June 2, 2010