Attic stairways are frequently overlooked as a source of heat loss in the home. Often, well-insulated attics do not provide any insulation over the stairways. This is often the case for folding stairways which are stored in an attic when not in use. Such stairs are sometimes called pull-down stairs.
Typically, such folding stairways are permanently installed in homes during construction. In the down position the stairway allows access to the attic. In the up position the stairway is stored above the ceiling level in an area of about ten square feet. The stairway is folded into a compact configuration and a thin, flat door conceals the stairway from below. The flat door is often one quarter inch thick plywood or the like and provides very little thermal insulation. The heat loss through this structure significantly effects the cost of heating and cooling the living area below the attic.
This problem has been addressed by a thermal stairway cover distributed by Pearson Industries, Ltd. of Conshohocken, Pennsylvania, incorporating a relatively heavy stairway cover including a plurality of folded sections. This design, while reducing the heat loss, was flawed because of problems associated with the danger caused by its weight and possible risk of catching an operators fingers as the sections are being folded or unfolded.
Another design was simply an overturned tub that was positioned over or around the frame around the stairway opening. The rather heavy tub was simply flipped over to gain entry to the attic. Again, this means of closing the stairway was somewhat awkward and dangerous to use because of its shape and weight. Both of the above-described techniques were unusable by older persons and others of limited physical strength.
Since energy efficient house designs are so important, a simplified, safe device to prevent heat transfer through an attic stairway is needed.