Solar Spotlight: Vintage Oaks Installation Puzzle Solved with String Inverters

Vintage Oaks, a senior living community located in sunny Citrus Heights, Calif., decided to upgrade their facilities by adding a photovoltaic (PV) system. The 18-building complex boasts mature landscaping with large shade trees, making it an idyllic place to live but also presenting a possible challenge for solar.

PV design is simplified with SMA’s free software,

PV design is simplified with SMA’s free software,

With several separate buildings located across the grounds, multiple roof orientations and shading – competitors might argue that micro inverters would be the only solution available. However, string inverter technology turned out to be the most reliable and cost effective tool for the job!

About the System

Developer USA Properties Fund, Inc. partnered with Beutler Corporation, a Northern California solar installer, to make Vintage Oaks one of the largest multi-family solar retrofit projects in the United States. Beutler Corp. designed the 500-kilowatt, decentralized PV system consisting of 2,640 PV modules and 98 SMA Sunny Boy string inverters.

Decentralized PV Design

To maximize the property’s shade-free areas, a decentralized concept was used to install PV across the rooftops of 16 buildings and 17 carports. By strategically placing modules and installing one string inverter per roof orientation, Beutler Corp. avoided shading issues, maximized production, reduced installation time and saved money on equipment costs.

“It would have required thousands of micro inverters to produce the energy created by 98 Sunny Boy string inverters. Micro inverters are a useful addition to any solar installers’ portfolio when shading absolutely cannot be avoided. But, from a PV design perspective, installing solar in a shaded area just doesn’t makes financial sense … especially if there is an alternate solution available,” said Curt Wylie, solar department manager for Beutler Corp.

Attractive for New Residents
Beutler Corp. installed solar using a decentralized PV design concept across rooftops and carports.

Beutler Corp. installed solar using a decentralized PV design concept across rooftops and carports.

The system is now producing 728,941 kilowatt hours (kWh) of electricity per year, helping offset power needs for the senior community’s 241 apartments by as much as 86 percent. Many residents have even reported receiving utility bills less than a dollar!

“For someone who is living on a fixed income, having a utility bill be zero in some months certainly makes a big difference,” said Judy Brown, a new resident at Vintage Oaks.

Brown added that in addition to the well-maintained grounds and lively atmosphere, the major deciding factor for moving into the senior living community was the promise of a low monthly utility bill. Vintage Oaks is proud to leverage solar as an amenity not offered by most of their competition, and it has proved to be a powerful marketing tool.


Solar Spotlight aims to highlight SMA inverters in real-world situations. Email us with information about your SMA-powered PV projects at



  1. Anthony Cotton
    Anthony Cotton says:

    Interested in getting a bit more info about this configuration. We are looking into solar for our HOA community here in the Philadelphia suburbs. It will be a single ground mount array of similar size… am also looking into being able to island the community during an outage and handle critical loads during the day. Anticipating adding some EV’s that ultimately will be able to assist in backup power when Solar is not producing. Was considering Sunny Boy/ Sunny Island configuration. Would like to connect with “local” rep for more detail investigation.

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