The US Energy Department says that in a typical residential or commercial building, about 42 percent of energy is lost through doors, roofs, attics, walls, floors and foundations – known collectively as the building envelope.
In the winter months, windows can account for 10 to 25 percent of a home’s utility bill through heat loss.
To address these energy losses, the Energy Department is investing $9 million in building envelope technologies, including high-efficiency windows, roofs, and heating and cooling equipment. This new investment supports six advanced manufacturing projects in California, Connecticut, Idaho, Maryland, Missouri and Tennessee that advance energy performance. This includes:
- about $6.5 million in four projects to develop highly-efficient, cost-effective heating, ventilation and air conditioning (HVAC) systems;
- about $3 million to two projects that focus on building envelope materials.
For example, St. Louis, Mo-based Unico will receive $2 million to develop a cold-climate heat pump with a variable speed compressor that will maintain capacity and efficiency even at very low temperatures. The University of Idaho will design and demonstrate a roof sandwich panel that uses foam material to increase building thermal efficiency and helps reduce construction costs by 25 percent. Lawrence Berkeley National Laboratory will develop and test highly insulated, easy-to-install windows that use automated shading that can capture or repel heat depending on the season.
While US energy use per capita was fairly consistent from 1990 to 2007, building improvements in efficiency for space heating and air conditioning have helped achieve a reduction in the last five years. Nearly 60 percent of homes now feature energy-efficient, multi-pane windows – up from 36 percent in 1993. About 40 million households have used caulking or weather-stripping to seal air leaks and drafts and 26 million have added insulation. The US Energy Information Administration expects that energy use per capita will continue to fall by an additional 15 percent through 2040.