Consider a house in Denver, Colorado, has the following building characteristics:

• Exterior walls with a total R-value of 19 (i.e., R = 19 hr·°F·ft2/Btu = 3.35 °C·m²/W) insulation and total area of 1,124 ft² (104 m²).

• A roof with a total R-value of 30 (i.e., R = 30 hr·°F·ft²/Btu = 5.28 °C·m²/W) and insulation and total area of 1,540 ft2 (143 m²).

• Double pane clear windows with R-value of 2 (i.e., R = 2 hr·°F.ft²/Btu = 0.35 °C·m²/W) insulation and total area of 185 ft² (17.2 m²).

• A ventilation rate of 0.30 ACH with a total volume of 13,860 ft3 (392 m³)

Determine the maximum breathing wall efficiency for this house and estimate the annual potential heating energy savings using 6,000°F-days for Denver and a furnace annual average efficiency of 0.85 . Assume the house is heated 24 hr/day.