These days a non-contact thermometer is not cost prohibitive so you could analyze the temperature of he pipe but if you cut the bundles open and start laying them out I doubt they will stay warm very long. You don't have much thermal mass there.
This sounds like a place for a controlled experiment I guess but it doesn't really get cold enough here to do it. You could get some pieces of PVC in a couple of appropriate sizes, leave it in the house/office for a day or so to be sure it is warm, then take it outside on a cold day and see how long it takes to get to the same length (temperature) as samples that were stored outside.
