Cost-benefit analysis of net zero energy campus residence

In response to both global and local challenges, the University of Dayton is committed to building a net-zero energy student residence, called the Eco-house. A unique aspect of the Eco-house is its cost effectiveness. This paper discusses both the design and cost-benefit analysis of a net-zero energy campus residence. Energy use of current student houses is presented to provide a baseline for determining energy savings. The use of the whole-system inside-out approach to guide the overall design is described. Using the inside-out method, the energy impacts of occupant behavior, appliances and lights, building envelope, energy distribution systems and primary energy conversion equipment are discussed. The designs of solar thermal and solar photovoltaic systems to meet the hot water and electricity requirements of the house are described. Eco-house energy use is compared to the energy use of the existing houses. Cost-benefit analysis is first performed on house components and then on the whole house. At a 5% discount rate, 5% borrowing rate for a 20 year mortgage, a 35 year lifetime, and an annual fuel escalation rate of 4%, the Eco-house can be constructed for no additional lifetime cost.