Rob Jenkins (Herpcam) and I conducted a coast-to-coast shipping experiment last winter during the week before Christmas where we obtained two 4-day thermal chart recorders... one for the inside of the box and one secured to the outside of the box. The box size was 14x10x10 with a 1" thick molded styrofoam insert that closes up like an ice chest. The volume of the box would have been less than 1 cubic foot.
I packed the box with shredded newspaper and placed the temerature controller inside, and secured two 30-hour heat-packs inside, one on each opposite side. I turned on the temperature recorders, sealed the box, and attached the second recorder to the ouside of the box. (Pics below)
First, I sent Rob the container from the west cost to the east coast via UPS Overnight Air guaranteed delivery by 10:30 am. The temperatures here were in the low 40's to upper 30's, below freezing in Louisville, KY where the UPS hub is, and in the mid-upper 30's in Mariland when the shipment arrived at 10:00 the next morning.
Rob then opened the box, removed the heat-packs, and replaced them with two new ones. He then sealed the box back up and shipped it back to me via USPS Overnight Priority Mail guaranteed to be delivered by noon the following morning. Par for the course, (
especially during Christmas week) the package took 3 days to arrive back to me.
When I removed the the chart recorders and pulled out the yards of tape, the first thing I did was begin to extrapolate the data into an time vs. temperature Excel spreadsheet, first with the data from the inside of the box, and then compared it to the data from the outside of the box. I was looking for how hot it got inside the box over the 16 hour trip, and how long the heat lasted. Likewise, I wanted to determine how cold the external temps were compared to the internal temperature.
Here is the graph that was generated from the data: