Problem $1.$ Install ten storm windows over existing single$-$pane windows in a house located in Estero, Florida. Table $1$ below shows the annual building energy use.

Initial cost: $$5000$

Expected life: $25$ years

Study period: $25$ years

Discount rate: $3\%$ per year

Replacement schedule: None

Residual value: $$0$

Electricity price: $$\frac{0\mathrm{.}12}{k}Wh$

Table $1.$ Annual building energy use:

$\backslash$table$[[$Description$,$With existing windows,With storm windows$],[$Space heating,$1,200kWh,1,000kWh$