You're considering installing a 4-foot-high by 8-foot-widepicture window in a north-facing wall (no solar gain) that now hasa total R (specific thickness of material) value of 23. As acompromise between initial cost and energy savings, you've chosen astandard double-glazed window with the value of R is 2.0. As aresult of installing this window, how much more oil will you burnin a 6-month winter heating season with an average outdoortemperature of 25F and an indoor temperature of 68F? Assume youroil furnace is 80% efficient.
