# A Gnuplot script to produce the graph on this page
set term png size 800, 600
set grid
set out 'energy.png'
a = 84 # h K
g = 300
f(u,x) = u * a * x
fw(u,x,w) = w * g + 1/(1/u + 1/(0.035/w)) * a * x
set title \
'Heat through 1 m2 of a wall during cold times (3500 d.K/a), \
with/out added insulation (lambda=0.035 W/(m.K))'
set ylabel \
'kWh including ev. those from energy-intensive (300 kWh/m3) insulation'
set xlabel 'time / 1 year'
set key left
plot [0:60] [0:1500] \
f(1.4,x) title 'u=1.4, 0.45 m solid brick wall', \
f(0.38,x) title 'u=0.38 demanded by CZ standard', \
f(0.25,x) title 'u=0.25 recommended by CZ standard', \
f(0.1,x) title 'u=0.10, a good passive house value', \
fw(1.4,x,0.5) title 'u=1.4 originally, 0.5 m of added insulation', \
fw(0.25,x,0.5) title 'u=0.25 originally, 0.5 m added' with points 3,\
fw(1.4,x,0.33)title 'u=1.4 originally, 0.33 m added' with points 1 , \
fw(0.25,x,0.33) title 'u=0.25 originally, 0.33 m added'
quit