5. Compare the life-cycle costs for three roof insulation R-Values to determine the most cost- effective solution over a 40-year life. Alternative Alternative Alternative A B C R-40 roof R-60 roof R-80 roof insulation insulation insulation Description with a 30- with a 30- with a 30- year design year design year design life life life Cost of R- Cost of R- 60 roof 80 roof Cost of R- insulation insulation 40 roof less the less the Initial insulation heating heating system Investment system demand demand reduction reduction ($165,700) ($178,600 ($194,800 - $7,500) $14,350) Annual cost Annual cost Annual cost of heating of heating of heating Energy Cost ($2,454 per ($1,635 per ($1,227 per year) year) year)