For 40 years, the Energy Department’s Weatherization Assistance Program (WAP) has focused on advancing energy efficiency in the residential sector, but recent developments in the solar industry have allowed the program to integrate solar photovoltaic (PV) technologies into its weatherization services. In August, Colorado became the first state to complete installation of a rooftop solar PV array as part of its services.

The Energy Resource Center installed a 2-kilowatt (kW) solar PV system at a WAP-eligible home in Colorado Springs. It’s estimated the system will produce more than 3,000 kilowatt hours (kWh) in its first year and net roughly $6,200 in energy cost savings over 20 years. Additionally, the home was retrofitted with a number of weatherization measures, including insulation in both the attic and the walls, low-flow showerheads, replacement of incandescent bulbs with compact fluorescent, and installation of a new dryer vent kit. Two carbon monoxide detectors and two smoke detectors were installed to improve the health and safety of the home. These upgrades are projected to save approximately 32 million British thermal units over the lifetime of each measure.

WAP requires that all its home performance services be cost-tested through an approved energy audit to determine that the savings-to-investment ratio is one or greater. The continued decline in the price of solar PV has made it possible for rooftop PV solar to meet this requirement. Residential solar PV prices, measured in dollars per watt, fell 50% from 2010-2015, according to the Energy Department’s National Renewable Energy Laboratory. The cost reduction was driven by many factors, including hardware costs, policy incentives, and leasing options. The Energy Department’s Sunshot Initiative is dedicated to driving the residential solar PV price down to $1.60 per watt installed costs by 2020.

Combining rooftop solar PV and weatherization services may also produce greater energy cost savings for the homeowner. Traditional weatherization services ensure that a home is “solar-ready” by cutting energy bills before solar installation. In this way, households ultimately receive a solar system that’s appropriately sized and priced to their needs.

This project offers a glimpse of what’s next in the field of weatherization and demonstrates what other states can do to expand services. The falling costs of solar panels have enabled them to be added to the weatherization package.