Significant Improvements in Energy Efficiency Characteristics of the US Housing Stock
Compared to 2009, single-family homes built before 1980 are now better insulated, have relatively newer heating equipment, and are more likely to have undergone an energy audit. These and other energy-related characteristics of the owner-occupied stock, shown in Table 1, are consistent with the expanding size of the home improvement industry over the past few years, with particular growth in energy-sensitive projects. Homeowners’ annual spending for related projects—including roofing, siding, windows/doors, insulation and HVAC—expanded from $50 billion to nearly $70 billion over 2009-2015.
The transformation of the existing US housing stock toward greater energy efficiency also reflects a wave of energy-related incentives for HVAC and building envelope upgrades put in place following the rise of energy prices in the mid-2000s. At the federal level, one of the biggest initiatives was the Obama administration’s American Recovery and Reinvestment Act of 2009, which extended and strengthened tax credits for energy improvements to existing homes, including insulation, windows, roofs, water heaters, furnaces, boilers, heat pumps, and central air conditioners.
Despite recent progress, there is room for growth. As of 2015, 17 percent of single-family homes built prior to 1980 were still reported to have ‘poor insulation’, and only 11 percent had received an energy audit. By comparison, a recent profile of newly constructed homes (built after 2009) showed only 1 percent of residents reporting ‘poor insulation’—an impressively low share. Moreover, nearly 90 percent of new homes come with double- or triple-pane windows. Bringing older homes up to this higher standard will require significant investments to the existing stock.
At the same time, only 5 percent of new homes have smart thermostats—a relatively inexpensive but potentially high-payoff upgrade—and a similar share have energy-saving tankless water heaters. These lower shares suggest room for growth in energy-efficient technologies in new and old homes alike.
Renewable technologies, particularly solar energy, are also showing signs of growth. As of 2015, nearly 6 percent of recently built homes reported on-site solar generation, a relatively small share, but nearly triple the incidence in older homes. Thanks to the Consolidated Appropriations Act of 2016, US taxpayers can still claim a credit of up to 30 percent of expenditures for photovoltaic and solar thermal technologies placed in service in their homes. Several US states also now provide consumers with credits for net excess energy generation, further increasing the payoff for installing renewable energy systems.
With recent declines in energy prices, however, there is some question of whether homeowners still have strong incentives to pursue energy-efficiency improvements. Since 2015, the consumer price index for energy has hovered around 10 percent below its average for the prior ten years (2005-2014). If this trend continues, further progress in energy-related improvements will probably depend even more on consumer preferences and finances, in addition to changing building and product codes, and evolving industry standards.
Data used in this analysis comes from a newly released 2015 Energy Information Administration survey that tracks the energy-related characteristics of all US residential units. Further results detailing energy consumption intensity (or usage per square foot) will be released in 2018, enabling deeper analysis into the evolution of energy efficiency in US homes.