A room has two $($external walls with two windows$)$ and the roof. Wall $1$ has window $1$ and wall $2$ has window $2.$ The $U-$ values for these envelope parts are shown in this table:

$\backslash$table$[[,$Roof,Wall,Windows$],[$U$-$ Value w$/$m$2.$ K$-$Un$-$insulated,$3\mathrm{.}1,2\mathrm{.}8,3\mathrm{.}7],[$New U$-$Values after insulation,$0\mathrm{.}8,0\mathrm{.}6,2\mathrm{.}1$ & sealed$]]$

The cost for adding insulation and replacement of windows $=$$$2500$

Cost of electricity $=$$$\frac{0\mathrm{.}15}{k}Wh.$

Heating hours $=1200$ hour $\frac{?}{?}$ year.

Cooling hours $=1500hrs.\frac{?}{?}$ year

Nach $($no sealing$)=\frac{1\mathrm{.}5}{?}$ hour

Nach$($sealed$)=0\mathrm{.}5$ times$/$ hour

$T_{\text{m}\text{i}\text{n}}($winter$)=5C,T_{\text{m}\text{a}\text{x}}($summer$)($winter