double glazed window

That day I was on the bus and gazing at the double glazed window. It's quite easy to spot it cos it's generally quite thick compared to normal windows. (i didn't test it out with the red emergency hammer though)

If we use the Fourier Law of Conduction (Qx = -kA dT/dx) and Newton's Law of Cooling (Qc = hc A dT), assuming the glass is 4mm thick, the air gap is 5mm thick, outside temperature is 32 degree C while inside temperature is 23 degree C, plus all kinds of boring values and constants and assumptions, then we find that a double glazed window can cut down up to 65% of heat transfer.

But if I decide to fart, then the calculation won't be valid anymore cos I introduced forced convection.

(I had ME3122 Heat Transfer test yesterday)