Plot: Landscaping contractor Roger Cook and host Kevin O'Connor bundle up and head outside for a few lessons on the different types of snowthrowers and how to use them properly. Back in the barn loft, Roger and Kevin, along with plumbing and heating expert Richard Trethewey and general contractor Tom Silva ask, "What is it?" Then, Tom makes a housecall to help a homeowner replace an old, drafty exterior door with a new pre-hung, energy-efficient unit