Page 48 - Zero Net Energy Case Study Homes-Volume 1

CASE STUDY NO. 2
FORTUNATO HOUSE RENOVATION
(Above) Electric vehicle charging.
Plug Load and Equipment
Most of the home appliances are Energy Star7—refrigerator, dishwasher and washer-dryer.
Cooking is done in either the speed cook oven or on the induction cooktop8.
There are two electric vehicles that must have access to electric charging capability in this garage for overnight charging, a significant electric equipment load that is added to the overall energy use of the house. Even with this added regular load, the meters recorded an annual performance of zero net energy for the house plus the two cars, indicating a remarkable “right- sizing” of the solar PV system.
Control Systems
The owners opted to have all controls and systems operated manually, aside from thermostats associated with the baseboard heating units and vacancy switches in the bathrooms. (The va- cancy switches turn off lights or fans if no motion is detected in those rooms.) This is worth not- ing because of the many “smart” systems now available, including remote controls using mobile phone apps.
Overall Evaluation of Design Strategies
There are a number of non-profit building industry organizations that promote green building practices through their programs of education, benchmarking and recognition of successful sus- tainable building designs. The common method of recognizing best practices is a point-based rating system for sustainable design strategies and features that are employed. This is typically a point-system, where points are awarded per feature or degree of performance. A total point score determines a “Rating” for the building, allowing comparisons and standards to be applied.
For residential buildings, Build It GreenTM offers and maintains such a rating system for the build- ing industry and governments within California, known as GreenPoint Rated. Point categories include energy efficiency, water conservation, indoor air quality, resource conservation and com- munity. Points are determined by an independent third party GreenPoint Rater. For new houses, the complete range of point totals is typically 50 to 140.
The Fortunato House was evaluated by a GreenPoint Rater and was scored at 162 points, well above the usual maximum. Were it considered a new house, it would merit a “Platinum” rating on the New Home scale. It is also certified as ZNE by the International Living Futures Institute.
7 See About ENERGY STAR, https://www.energystar.gov/about
8 Induction cooking is a magnetically induced heating method for cooking as opposed to direct electric coils or gas burners. Of the three types, the electric coil is generally regarded as the least energy efficient, the poorest method for cooking because of its relatively slow response to con- trols and the least safe from casual burns. Gas burners have quick response to controls—their advantage over electric coils—but are a source of toxic chemical by-products and still have a serious burn risk. Induction cooking has all of the advantages of gas cooking, including the de- gree of control for cooking, is toxin- and carbon-free and the “burner” never feels hot to the touch. (Cookware must have ferrous content—stainless steel or cast iron, but not pure aluminum.)
Use of induction cooking, like the microwave oven when it first appeared, is a technological in- vention that must achieve a familiarity and an acceptance level among homeowners (and chefs). But it is the recommended choice for ZNE and ZNC homes. See the following article for a techni- cal comparison of cooktop alternatives:
(1) http://ovens.reviewed.com/features/induction-101-better-cooking-through-science;
(2) https://www.consumerreports.org/electric-induction-ranges/pros-and-cons-of-induction- cooktops-and-ranges/
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Zero Net Energy Case Study Homes: Volume 1