Philgreen Construction built this 1,576-square-foot multifamily home in Fort Collins, Colorado, to the high performance criteria of the U.S. Department of Energy Zero Energy Ready Home (ZERH) program.

With 7-kW of photovoltaic panels on each roof, these townhomes have achieved a true net zero HERS score of -1 with annual utility costs of only $60 per year.

Properly flashed fiber-cement-siding-clad walls, shed roofs, and exterior grading that slopes to drainage help minimize the risk of water damage in and around the durable homes.

An energy recovery ventilator and low- and no-VOC wood products, interior paints and finishes, and carpet and pad help to encourage better indoor air quality in this EPA Indoor airPLUS-certified home.

This EPA WaterSense-certified home has low-flow fixtures that reduce water and energy use.

The slab-on-grade foundation is wrapped with R-10 insulation both under and around the slab.

The vaulted ceilings were covered with 14 inches of open-cell spray foam insulation to provide R-50 of wall insulation value.

The walls were constructed of 2-by-4 studs staggered on 2-by-6 top and bottom plates and the wall cavities were filled with R-23 of dense-packed fiberglass insulation and sheathed with a coated OSB product.

A highly efficient (4.18 COP) ground source heat pump provides heating and cooling to the home.

High-efficiency, double-pane windows have low-emissivity coatings to reduce heat transfer in and out of the homes.