Page 71 - Zero Net Energy Case Study Homes-Volume 2

STRATTON-LEE DIY HOUSE
CASE STUDY NO. 8
Post-Occupancy: Observations and Conclusions
The owners are not seeking any certifications for this all-electric house, in spite of the verification of ZNE performance expected in 2020 after a year of operation after completion of construction. This is in keeping with the cost consciousness of the process employed from the beginning.
The timeline of the DIY process was much longer than planned or anticipated: almost three years rather than only one. The owners expressed the opinion that they were naively optimistic. In hindsight, they would hire more professional builders and tradespeople to carry out certain tasks. The owners kept a record of their time: the labor for the owners totaled 4,800 hours, av- eraging 25 hours per week or the equivalent of roughly three days at 8 hours per day. The own- ers estimate that if they had hired subcontractors selectively, then they could have reduced this DIY labor to weekend work, which would have been more tolerable over that period of time and traditional for a DIY project.
The cost was also underestimated: originally planned at $50,000, the total came to about $120,000, or ($90 per sq. ft.), without charging anything for the owners’ labor. Still, this is a very small fraction of the current cost of residential construction in California.
The general assessment by the owners is that despite the differences in work process that they would plan differently, there are no significant changes that they would make to the actual scope of work carried out. The work plan and choices made are judged to be sound and they achieved their objectives.
One observation about the heating/cooling system is that two mini-split units were required to keep the two isolated halves of the house habitable while work proceeded in each of the two phases of the work. They were sized for this condition, but when the construction was completed, the two areas were joined together, rendering the two mini-splits slightly over-sized for the whole house (a combined 3.8 tons for 1,323 sq. ft.).
Zero Net Energy Case Study Homes: Volume 2
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