I don't use the spare bedroom much,this is the one i put the foil on.
it faces east so it warms up in the morning.
The foil has stopped a lot of the heat coming through. Surprised by how much cooler actually.
Guessing around 1-2 degrees C. I can feel a clear difference.
Problem now is trying to open it at night to cool,as the foil keeps coming off when I slide half the sliding door window past the other half.
Living a few hundred Kms south around Bunbury or even further south certainly takes the edge off the intense heat.
Perth unlike other Capital cities can easily get on a run of 10 or more days of intense heat,sometimes a lot more.
Answer is i should buy an air-cond but then my electric bill....
Bunbury a lot cooler.
www.weather.com.au/wa/bunbury