Sustainable housing: Emergy evaluation of an off-grid residence: Fid-Bau Portal

Sustainable housing: Emergy evaluation of an off-grid residence

Rothrock, Heather

Highlights • Emergy analysis determined the emergy intensity of an off-grid house. • Sustainable construction is more costly in the short-term, but long-term can be of economic benefit. • Most emergy associated with building the house is from direct and indirect labor. • Annual operation costs are lower than average.

Abstract Sustainable construction aims to utilize environmental-friendly materials and decrease energy and material demands in the construction, operation, and maintenance of a structure. A potential obstacle to building sustainable infrastructure is the initial cost of construction, as environmental-friendly materials are often more expensive. To quantify costs with environmental trade-offs, inputs must be measured taking into account both quality and quantity. Emergy, a method that converts various energies to a common unit, the solar energy joule (sej), offers a more holistic evaluation because it takes into account the quality of inputs. Data on all inputs required to construct and operate a 176m² off-grid house were collected and an emergy evaluation determined it took 8.12E14sej/m² without service and 4.41E15sej/m² with service to construct the house. Labor and service accounted for 82% of the total. Annual emergy required to operate the house in terms of electricity, propane, water, and services associated with them was 0.05E15sej/m²/yr, a value less than those found in previous studies. Results revealed that a higher initial emergy investment into sustainable construction can result in lower annual operational emergy requirements, thus a potential emergy savings over the long term.