why is the isulation in the attic commonly thicker than the insulation in the walls of a house?

Answer 1

Heat rises.

Answer 2

Heat rises and cold comes down... not side to side.

Many warm climate cities/states don't have an ounce of insulation in the walls of older homes. When you get into cold areas the insulation R factor is almost the same in the walls as the ceilings in a warmer climate state.

It is all about the cost factor and money saved. Wall insulation is of little value in S. Calif or Florida, but in cold climate states such as PA & NY, the R factor in the walls is doubled.

Answer 3

Heat rises. Warm air is less dense than cold air. Since this is so the most heat loss occurs in the attic. While walls need to be insulated, the loss through walls is much less, so less insulation is OK.

Answer 4

because of the fact warm air rises, and chilly air sinks. for this reason, in wintry climate time, the appropriate temperature differential between indoor air and exterior air, will take place around the ceiling, attic and rooftop. So those grow to be the extreme region to insulate.

Answer 5

Most heat loss is through the roof. Heat rises

Answer 6

Heat rises. Therefore to keep the heat inside you stop it from going outside.