Affordable housing can mean a lot of things, from subsidized apartment buildings to single-family homes for working-class families. In increasing numbers, these types of dwellings are also highly sustainable.

Here are five ultra-green projects that also happen to be affordable.

Location: Kansas City, Kan.
Certification: Passive House, LEED-Platinum
Cost: $93 per square foot
Builder/Designer: The University of Kansas School of Architecture and Urban Planning’s Studio 804

Designed to exceed both Passive House and LEED Platinum standards, this Midwestern home uses minimal energy through affordable passive means. Planners relied on low-cost strategies such as louvers, thermal mass, high-performance windows, optimized insulation, southern orientation, and an airtight building envelope to obtain a 90% reduction in heating and cooling demand compared with a traditionally built home. In addition, an energy recovery ventilator works in conjunction with these strategies to temper fresh intake air with energy from the exhaust air, providing constant fresh air year-round.

The open living spaces allow natural light to flood the house, a principle tenet of the project’s energy-saving concept. The stacked master bathroom and main-floor bathroom are flooded with natural light through an internal two-story frosted glass wall, and operable glazing stretches the entire length of the southern side to encourage natural ventilation. Remote-controlled operable skylights create the only break in the northern envelope of the house.

The entire house was framed in engineered lumber. TJI joists allowed for the 12-inch wall and 16-inch roof depths needed to house thick cellulose insulation. Priced at $159,000, the residence was designed as an affordable spec house for qualified buyers with an annual income of no more than 80% of the target area median income.

Other sustainable features:
--durable Galvalume metal roofing
--highly efficient German-made Zech windows
--Ultimate Air energy recovery ventilator
--LED interior lighting
--drought-resistant landscaping

The Prescott Passive House received a coveted residential architect Design Award for the single-family housing category in 2011. Read what the judges had to say about this winning entry.