28 Sep '15, 11am

Battling Condensation on Attic Ducts

Battling Condensation on Attic Ducts

It doesn't mean much to report RH without the corresponding air temperature, and in relation to prevailing exterior temperature and RH. If we can’t locate both the interior and exterior temperatures and relative humidities on a psychrometric chart, we don’t get the whole picture and prevailing vapor pressure situation. Nor does it mean a lot to report RH without stating what sort of hygrometer A device that measures relative humidity of air. Mechanical hygrometers that rely on a coil of thin metal are not terribly accurate; electronic hygrometers available at most electronic or hardware stores are usually accurate to about plus or minus 2 - 3%. you are measuring the RH with. Inexpensive electronic hygrometers are quite often highly inaccurate. A minimum certified accuracy is +/- 5%; +/- 3% even better (pretty hard to get more accurate than +/- 3% unless you have a sling ps...

Full article: http://www.greenbuildingadvisor.com/blogs/dept/qa-spotlig...

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