Rising energy costs have a disproportionately greater effect on low-income families. Net-Zero Energy Homes are prototypes for affordable, energy efficient housing, located on urban infill lots in the north end of Hartford. Combining energy-use modeling with cost analysis, our design team specified highly energy efficient building components, including extra cellulose insulation in the walls and ceilings and high performance windows. We evaluated various heating, ventilation and air-conditioning systems to select the most efficient and cost-effective solution. Photovoltaic arrays (provided by state funding) on the southwest-facing roof of each house provide power. The developer has educated the new homeowners in the operation of the houses and will monitor the buildings’ performance over time to evaluate future improvements that would be beneficial.