Envelope-Driven vs. Occupant-Driven Loads

Challenge

Some energy consumption in a home is heavily influenced by the way homes are designed and constructed – or by the “building envelope” of the home – while other energy use is dictated by occupant use and habits. While some costs can be controlled by the building design, homeowners must also be educated on how to efficiently use their homes. For example, a tight, well-insulated home will require less energy to heat and cool than a comparable house with more air leakage and less insulation; the envelope drives energy needed to heat and cool. By contrast, plug loads, or energy use from items plugged into outlets (televisions, computers, hair dryers, etc.) is driven by the occupant.

Opportunity & Response

Rural Studio clearly differentiates what we can control through design and construction and what we can control through homeowner education and awareness. Energy modeling during the home design process can help housing providers and their clients understand the expected energy use – and, therefore, predicted costs – for envelope-driven systems such as heating, cooling, and ventilation. Post-occupancy monitoring ensures that these systems are operating as modeled. Additionally, post-occupancy monitoring allows Rural Studio to continue to actively engage with the housing provider and homeowner, and to provide the ongoing education necessary to help occupants understand how to use their homes more efficiently and reduce energy use and maintenance costs.

Response

Front Porch Initiative continues to collect ongoing energy use data on two houses constructed to beyond-code standards with Auburn-Opelika Habitat for Humanity (AOHFH). As energy to condition and ventilate the house decreases with more efficient systems, the share of energy devoted to plug loads becomes a larger share of overall energy use.

Implementation

Stevens Street