Page 97 - Zero Net Energy Case Study Homes-Volume 1

Post Occupancy: Observations and Conclusions
Data collection as part of the research study is ongoing and in general, all of the objectives of the project have been achieved by both the builder, Meritage Homes, and the other partners in the projects. The performance data has been collected and recorded without problems.
Two of the twenty houses in the ZNE Study Group actually performed at ZNE. Given that one of the objectives of this project was to explore ZNE house production within the financial and marketing constraints utilized by the competitive production house industry, this outcome may be both expected and positive. The houses of the ZNE Group, judging from the data, for example, can achieve ZNE with the addition of just a few PV panels. All of the houses “fit” in the larger development and cannot be differentiated based on their overall design. In addition, the builder developed firsthand experience in the construction of these high-performance houses, which is replicable and marketable.
Post Occupancy: Energy Use / Occupant Behavior
It is interesting to compare House #12 with the ZNE houses of Case Study No. 1, the spec house at 609 Marigold, and Case Study No. 2, the Fortunato House. They are approximately the same floor area (the Fortunato House is 80% the size of the other two), but House #12 achieved ZNE performance with a 4.0 kW system, while the house at 609 Marigold in Corona del Mar used an installed 10.9 kW system and the Fortunato House has an installed system of 6.5 kW.
Although there are some differences in the ZNE design features of the houses and the climates of the locations (inland versus marine), the primary difference is likely to be the result of user behavior. Given that the other houses in the ZNE Group of comparable size did not achieve ZNE performance supports this conjecture.
Another general observation by on-site observers of the research partnership, applicable to some of the houses that did not perform very close to ZNE, is that some of the buyers did not concern themselves with careful and frugal energy use since they considered that the solar en- ergy supplied was “free energy”.
Post Occupancy: Battery Energy Storage / Occupant Behavior
The buyers of the houses in the ZNE Study Group welcomed the battery energy storage fea- tures, but not for the technical reasons of assisting the electrical grid with the peak load shift.The reported desirability of energy storage was the maintenance of power to the house in a power outage, especially in the event of an emergency such as an earthquake. The buyers thought of it primarily as a resiliency feature.
Zero Net Energy Case Study Homes: Volume 1
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MERITAGE PRODUCTION HOUSES
CASE STUDY NO. 4