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A comment on Heat pumps of the 1800s are becoming the technology of the future. Parent comment

Re:Heat pumps of the 1800s are becoming the technology of th... by briHass on Monday January 16, 2023 @06:10PM (#34406784)
Interesting. The code for duct insulation in unconditioned spaces in the US is R8, and they're pushing for higher currently.

They also recently undid a long held myth about ducts buried in insulation leading to condensation issues. Most areas now allow ducts to be buried as long as you have R19 above and below, or R30 above. When I just installed a ducted mini for 3 upstairs bedrooms, I surrounded my R8 flex duct with R30 insulation.

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Re:Heat pumps of the 1800s are becoming the technology of th... by EricE on Monday January 16, 2023 @10:27PM (#34408799)
lol - it's not a myth. It's physics: https://www.youtube.com/watch?v=Vufih-WN5R4
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Re:Heat pumps of the 1800s are becoming the technology of th... by mrexroad on Tuesday January 17, 2023 @12:52PM (#34415851)
Fwiw, context of this video is metal duct work. You’re not going to see R-8 flex duct buried in R-30 begin to sweat when the AC is running. In terms of controlling the dew point, the duct is no different than the conditioned space at that point.

Like you said, it’s physics.

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