This home was imagined as a demonstration of a Zero Carbon future, including not just the home but also the daily transportation. The purpose was to engage society in a discussion to try to move forward to a future of renewable energy and electrified vehicles; it was therefore conceived as a package including the home, vehicle, and energy management system. In order to bring as much societal value as possible, we also wanted to highlight discussions of sustainability beyond energy. So while energy is clearly a focus, we also tried to demonstrate sustainability of the materials themselves, water use, waste, and occupant health. The project was developed by Honda, led by the Environmental Business Development Office (EBDO) within American Honda Motor Co., Inc.
The name “Honda Smart Home” refers to the Smart design and use of energy. We therefore began with a holistic, integrated design process considering all aspects of sustainability. As with most “real-life” projects, our site required specific layout features in order to make full use of solar access, while providing for access to the garage. To make full use of solar energy, our roof form is biased towards southern exposure with minimal roof penetrations to disrupt panel layout; and the North side is designed for natural daylighting. Every detail of design was similarly considered, which meant continuous discussion among the architect, HVAC designer, mechanical engineers, certification members, and EBDO leadership.
The basic viewpoint for the project was to first build the home as efficiently as possible: the envelope, HVAC system, lighting, appliances, and MELs. Then to allow the occupants to live without sacrificing quality-of-life. Of course, they are aware that they are living in a demonstration home, and that their usage data will be recorded; but the intent is not to try to coerce specific behavior. If the occupants need to run laundry or wash dishes, then the home should respond as requested, but if this would cause hardship for the electrical grid, then the HEMS machine will seamlessly step in to allow them to continue their daily routine, but also provide value to the grid. We therefore do not control any of the appliances with the HEMS machine. In extreme cases, we can use the thermal mass of the home to slightly shift the HVAC run times, but in general we only actively control the vehicle charging to minimize CO2 (and use the stationary battery to provide grid support). The home is oriented for maximum winter sun collection, but with careful design of the roof overhangs and addition of awnings to shade the South windows from summer sun. The home also takes advantage of the cool summer evenings by pre-cooling using only fresh air, and throughout the year ventilates primarily at times of day when the outdoor temperatures are preferable (note that this climate has low summer humidity which allows for this pre-cooling strategy). We are also able to track vented air from the central vacuum, range hood, or bath fans so that we do not over-ventilate on days that have supplemental sources of fresh air. We use a passive heat exchanger to recover heat from greywater, then further remove heat (mechanically) from that greywater as it percolates through our wetted boreholes. And of course, the windows provide excellent natural daylighting for most of the day (the lighting system uses daylight sensors to reduce consumption when enough light comes from the windows).
Find out more about this case study from ILFI here.