Monday, April 20, 2009

Insulation DOES Make a Difference

Back to work this morning in the home office. This is located directly beneath the attic area where I was crawling around last Saturday, air-sealing and carefully cutting insulation batts to fit.

The path of heat flow is much like water. If you want to stop a river's flow, a few big obstacles in the river bed just won't do the job-- you need to build a dam. Similarly, you can't insulate an attic without carefully covering the entire surface-- ensuring a snug fit between the ceiling joists, all the way out to the top sills of the walls.

Given the current outside temperature of 46 degrees, the boiler is operating, and the radiators are doing their job. This room is now noticeably warmer than it was before. Lesson learned: partial insulation has the same effect as no insulation. Dare I say it, last Saturday's adventure was worthwhile.

1 comment:

  1. Great point RE: partial insulation, and good water analogy! I always like to compare gaps and voids in insulation to holes in a bucket.. even a small hole means you will end up with an empty bucket.

    To be a bit geekier: to consider how a partially insulated area will perform, you have to take a weighted average of the U-value of the areas, not the R-value! (U values are often used for windows, they are simply the reciprocal of R-values, or 1/R). This means that a 1000 SqFt ceiling insulated to R-50, with 5 SqFt un-insulated area actually performs at R-40 overall. A 20% drop in performance from a 0.5% flaw!