What is a reproducible test to measure the r-value of an exterior wall? Or even a specific spot on a specific wall? It needn't produce an absolutely certain result, but a good estimate with known ...
Some people use aluminum foil to reflect heat on windows but I find it very depressing and bad-looking thing. My Chinese friends use 台州涂银反光窗帘布 but I have no idea what it is in English: they translated ...