Picture this: it’s a cold winter morning and you’re leaving for work. You just made some coffee and you want it to stay warm for the drive. What do you do? You pour it into a tumbler and seal it with a lid on top. This tumbler keeps your coffee warm much the same way attic insulation and air sealing do for your home. The stainless steel interior of the tumbler works like proper insulation, helping to keep heat from…