I have a small/ tall cooler that doesn't hold heat very well. Tried using it to make yogurt but it didn't hold the heat very well; the original yogurt making cooler is very small ( 4 -qt size canning jars) and too small any way. It is stryofoam and very thick walled. Looked at a new cooler today short, about 1/2 the height of typical plastic type cooler, but maybe too short. Reminded me of the LG. IT's $20. So it seems not all coolers are made equally--how well does yours hold the heat? And which did you use--plastic type cooler or styrofoam? ANd which brand? I'm off to the basement to find another cooler and test it for how well it hold the heat.