Case Study: Eclectic 1960s Home Transformed to Zero Net Energy with Solar PV

J.D. and Cher Donovan first considered solar for their La Mesa home ten years ago, but as real estate professionals, their plans were put off by the effects of the Great Recession on their income. More recently, their concerns about rising energy costs and mitigating their carbon footprint were revived. With the help of Spencer Rosen of Energy Integrity, a contractor they met at a Center for Sustainable Energy outreach event, they retrofitted their 1960s modernist home with energy efficiency measures and a solar photovoltaic system that supplies all of their electrical needs.

The Donovan’s three-story, 2,700-square-foot house presented some unique challenges for energy upgrades with floor-to-ceiling windows, multiple trapezoid-shaped rooms and complex ductwork. The locations of the air intake and return vents created poor circulation and drastic temperature differences between the upper and lower floors that the HVAC system couldn’t overcome. In addition, an energy audit showed their home had air leakage of nearly 60 percent, meaning much of the heating and cooling was wasted. It was no wonder their utility bill averaged $500 per month and peaked to $700.

The interior design intricacies necessitated an increased scope of work including expanded efficiency measures and a sizable solar system to get the house to net zero energy. Energy Integrity was able to guide them into the Energy Upgrade California® Home Upgrade program, which provided incentives for some of the home improvements.

“Use a contractor that understands the big picture of how to create a totally buttoned-up home – not a contractor that just sells solar panels.” – Cher Donovan

Financing

The Donovans financed their project by a Merrill Lynch Loan Management Account with a 3.5 percent interest rate. By eliminating a $500+ electric bill and getting utility credit for excess solar generation, they expect a 5-6 year payoff. They also took advantage of the 30 percent federal investment tax credit for the solar system.

Results

The Donovans say their home now has comfortable indoor temperatures and report energy savings exceeding $6,000 a year. Their PV system completely offsets their electrical needs and is sized to accommodate a planned future plug-in electric car. They believe the solar and energy upgrades greatly improve their home’s value, for both sales and potential renting.