I have copper water pipes in crawl space, about 1/3 of it has frostex heat cord on it, the other 20' just have regular pipe insulation around them, sometimes this area gets to 32 degrees F - my question is at what temp will pipe freeze that has been wrapped in insulation?

Either 31 or 32 degrees.

About 32 degrees, if it stays cold long enough. Insulation does NOT prevent freezing or add heat to the pipe. If just slows the process down until things warm up.

'scratch' the words 'until things warm up'

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

The entire run of water line should be single or double wrapped with Frost-Tex Heat Cord and then Insulated with heavy insulation. You can't do the same with the old stuff called heat tape of yester-year, but you can do it with Frost Tex Heat Cord. This way temps can go way down and you will have water.....

Best Wishes

quote; 'until things warm up'

Why? NOthing's going to thaw out until the pipe gets "warmer". Even cold water flowing through it would be "warmer" and thaw the line.

then insert 'freezing' between 'the' and 'process'


as written, it is misleading

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

quote; as written, it is misleading

Only misleading to YOU.

AFTER 'things warm up' the insulation STILL continues to slow the rate of 'heat transfer'.

'Things warming up' has no bearing on what the insulation DOES.

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Insulation slows heat transfer, but from which direction depends on both the water temperature inside the pipe, and the air temperature outside the insulation. Arguing about details is pointless, everyone is already on the same page now.

that was my intention

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Actually, I think you just wanted to be obstreperous.