Shifting to Zero

September 30, 2019
A house built around three trees in the Eagle Rock neighborhood of Los Angeles, CA: passive daylighting, recycled lumber, recycled fly ash concrete, solar energy, grey water recycling, rain water capture, mobile shade panels.

As concern about the climate crisis grows, people are searching for solutions to decrease their carbon footprints. Net-zero homes are one way to help achieve deep decarbonization.

A net-zero home is a highly energy efficient residence that produces as much energy as it uses in a year. Although connected to the grid, these homes have a net-zero energy bill because solar, geothermal, or another onsite renewable energy powers everything in the home from heating and cooling to lighting to powering an electric vehicle (EV), while energy efficiency decreases the energy required for these uses.

I visited a recently constructed net-zero home in Seattle that boasted an induction stove, EV charging readiness, recycled building materials, stormwater runoff management, and solar panels.

An induction stove is powered by an electromagnetic field, which heats dishes much faster than a regular electric stove because the current is transferred directly from the cooktop to the pot without waiting for the burner to get hot. Induction stoves are also safer than gas-fueled stoves because burners won’t turn on without a pan on them, and an induction stovetop doesn’t become nearly as hot as one that uses natural gas.

While featuring many new “smart” appliances and some recycled materials, the net-zero house, I visited was essentially a high-tech McMansion, boasting six bedrooms and four floors and filling nearly the entire lot in the Montlake neighborhood, leaving a minuscule amount of space for a yard. At least four townhouses could have been sited on the same land area. High density housing like apartments and townhomes is more energy and land efficient than single family homes, and decreases sprawl.

Furthermore, onsite energy generation could have been drastically increased. Solar panels covered only a tiny portion of the roof, which had been built east/west facing rather than north/south, a more productive layout for solar. If the roof had been designed with energy generation in mind, more solar panels could have been placed on all available roof space, allowing the house to generate even more electricity than necessary to power the home and contribute clean electricity back to the city’s grid.

While the garage was advertised as EV-charger ready, there was no charger located on the premises. Instead, wiring was in place to install an appropriate outlet and charger should the owner decide to purchase an EV, which meant the owner would be required to pay an electrician to install a charger.

On the plus side, the building was fully electrified, with an electric heat pump and water heater. Natural gas was not used anywhere on the premises. Heating and cooling buildings with fossil fuels accounts for 10 percent of U.S. greenhouse gas emissions so  eliminating natural gas and other fossil fuels from houses is critically important. In Seattle, more than 95 percent of electricity is generated carbon-free, so switching buildings to electric heating and cooling and installing energy efficient features would make a significant contribution to reducing the city’s carbon footprint.

Although the net-zero home I toured had some flaws, it was a good demonstration that the technology exists to lower residential carbon footprints. It was also an opportunity to demonstrate that homes can be more environmentally friendly without sacrificing comfort. However, if you really want to live sustainably, choose a LEED certified townhome or apartment building.