Abstract
This chapter will discuss heat loss through doors, which is reasonably similar to heat loss through windows discussed in Chapter 3, and sustainability techniques that help improve bottom line.
Keywords: Doors, door insulation, U-value R-value, payback period, heat transfer, heat loss, cost of heating, cost of cooling, old door, draft, draft cost, draft cost calculation, heat loss, heat loss across door, type of door, door design, door shape effect, when to replace door.