Thursday, October 16, 2008

Weatherization Training in Physics Class


The Ken Jones-led "Weatherization Training at School" was a total success. I definitely need to write him a thank you note. Students learned about how thermodynamics principles connected to home heating, and got to see weather stripping and where on a door/window it goes. We did some experiments with tin foil boxes and ice cubes - it was great. Specifically we built two boxes out of tin foil. One went over in a corner away from everything. One went on the vent, which was spewing room-temperature air. So which melted first? The one on the vent. Why? Convection. BAM! Students learned that convection is just as important as conduction to account for the heat loss in a house.

Some interesting nuggets:
  • A 1/8" gap around a door (which is typical) is the same area as a 4" hole in your wall. Seal that up!
  • Frequently the holes that are cut for cable to enter a house are not sufficiently sealed up/insulated.
  • The "pink stuff" is not as awesome as people once thought. Apparently it's good for preventing conduction, but is quite awful at preventing convection. You can blow air right through it, and so if there's a way for air to get into the outside part of your wall, and there's an opening to the outside somewhere higher up, it can create a heat pump through the walls of your house!
  • The best windows ever made (for insulation purposes) have an R of 3.5. Whereas regular 1" foam insulation (with tin-foil on the sides) is R: 7.5
Ok that's it for now :)

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