Improving Energy Efficiency in Existing Homes Remains Priority for PATH

The "Energy Efficiency in Existing Homes" Technology Roadmap outlines research and development to make their vision that by 2010, consumers will be able to substantially improve the energy efficiency of their homes and cut their energy expenditures a reality. It describes the challenges, and outlines activities and accomplishments needed. These include promoting new technologies, evaluating products and processes for retrofit, building capabilities among trade contractors, and identifying potential consumer incentives.

Data Provides an Overview of Energy Efficiency

Relevant data from the Energy Information Administration's (EIA) Residential Energy Consumption Survey (RECS) is used in this Roadmap to show current levels of energy consumption. RECS data provides a great deal of information that can be used to estimate potential energy savings from different types of technological improvements-helpful in assessing potential energy retrofit technologies for use under PATH. According to the survey, energy use per housing unit has declined since 1978 from 77 million housing units using 10.6 quadrillion BTUs to 101 million housing units using 10.25 quadrillion BTUs. This change has been attributed primarily to reductions of energy required for space heating due to improved insulation, windows, and heating equipment.

While homes are generally more energy efficient than they were 20 years ago, there is room for improvement using new and existing technologies. The Roadmap divides areas for improved energy efficiency into six categories, intended to encompass the whole range of approaches available for use in addressing residential energy consumption.

Improving Efficiency from the Outside In

Gaps and cracks in building exteriors contribute significantly to inefficient energy use. The first Roadmap section discusses materials that seal cracks in housing envelopes. Air leakage through the building envelope is a major contributor to heating and cooling loads in homes of all ages, but it is particularly problematic in older homes. High air leakage around window and doorframes or through holes for pipes, wiring, and fixtures results in a drafty, uncomfortable winter with noticeable cold spots around the home's perimeter. An increasing variety of caulks, foams, and other types of weather stripping are available for use in air sealing. Some products are for general use and are sold to consumers; others address special purposes. Improvements to housing insulation and windows are also discussed in-depth as a necessary step to increasing the energy efficiency of homes.

Other Areas for Improvement

The remainder of this Roadmap discusses how to increase energy efficiency in:

• HVAC systems and controls,
  
• Appliances and lighting, and
  
• Distributed generation.

All efforts to increase energy efficiency in technology must also be complemented with new outreach strategies and tools. While not technologies in themselves, the adoption of these technologies by providing the important linkages between potential end users and available technologies.