$7.)$ We have a masonry wall that measures $7-$inches in thickness and has an $R$ value

of $0\mathrm{.}51.$ The wall has an outside air film $(R=0\mathrm{.}15)$; inside air film $(R=0\mathrm{.}68)$; a $2-$inch

thick furred space with R$-4/$inch insulation and covered by $\frac{1}{2}-$inch drywall. The

wall is the perimeter wall of a building that measures $10-$ft in height by $1,000$ feet in

length. The design temperature difference is $66F.$ What is the heating load

$($BTUh$)?$