This article is only available to GBA Prime Members Chuck Reiss, a builder in northwest Vermont, had a bold plan in 2007: he wanted to build a cluster of six superinsulated homes on a 24-arce site in Hinesburg. Reiss planned to install a roof-mounted PV array on each house, with the goal of making the homes net-zero energy, or close to it.The homes would occupy about 10 acres of the site; the remaining 14 acres would remain agricultural. For anyone interested in passive solar design, the acreage was extremely attractive; architect Rolf Kielman (TruexCullins Architects) describes the sloping site as “a south-facing bowl.” The site is within easy walking distance (via a pedestrian path) of the shops in Hinesburg village.The project, known as South Farm, now has five homes; the sixth will be built soon. It’s been five years since the first homeowners, David and Carrie Fenn, moved in, so it’s a good time to find out how well the homes have been performing.Each of the homes that Reiss built is a custom home; however, the homes share many similar characteristics and specifications:According to Reiss, the size of the PV arrays was a compromise. “I think people are willing to put money into PV, up to a point,” Reiss told me. “But we didn’t size the systems to be at net zero.” According to energy modeling projections, the owners were likely to use about 5,500 kWh of electricity per year — more than the 4,000 kWh per year that the 3.9-kW PV arrays were expected to produce.All of the homes sold for more than $425,000.Fortunately for the owners of homes at South Farm, the local utility, Green Mountain Power, has a very favorable rate schedule for homeowners with grid-tied PV systems:Here’s an example of how this works: Let’s say you use 500 kWh during the month… Start Free Trial Already a member? Log in Sign up for a free trial and get instant access to this article as well as GBA’s complete library of premium articles and construction details.