Insulation is a home's blanket. The image conjured by artists is of a thick, warm quilt draped over the shoulders of a living, breathing, pointy-headed house with windows for eyes and a door for a mouth.
This characterization is presented often in newspaper advertising and in story books. Somehow, artists never take their analogy to its logical conclusion. If a house is like a human head, and the door is the mouth, then what are we humans? Spit? Bubble gum? Or God forbid, chewing tobacco? I'm just glad they don't turn the door into a nose.
Whatever insulation is to artists, to the common man it is another layer to protect him from elemental forces such as wind and temperature extremes.
Insulation, in the form we know it, is a fairly recent development. Until about thirty years ago, many houses were built with little or none. Siding, sheathing and drywall were all the protection considered necessary.
The house I share with my wife was built in 1958. When I removed some of the siding to begin the addition, I discovered that the insulation was far from being a warm quilt. It was one of those ratty, worn bed sheets you would have long ago consigned to the rag bag. One inch of black sheathing skirts the entire structure. The layer of dust in the attic is thicker than the fiberglass. (That doesn't keep the fiberglass from getting under my clothes every time I make a foray up there.)
Though insulation has not always been a building priority, government has now regulated us to the other extreme. New houses have become so well insulated, so airtight that they have poor air circulation. It is not unheard of for a local B-B PUD to mandate high levels of insulation, while at the same time dictating that vents to the outside be installed. If they had simply not legislated airtight rules in the first place, it would have saved a lot of trouble for everyone.