Electricity & electrical wiring
To keep the home as airtight as possible, the wiring configuration minimizes punctures in the exterior plywood sheathing. To accomplish this feat, the majority of outdoor wiring (serving the outside lighting, greywater pump, electric vehicle charging system) is addressed by an outside electrical panel. Further, as noted by the pictures, cuts through the outer wall have been made with the smallest hole that would allow the wiring through and sealed from the inside.
PV is to be added post-construction, hopefully via a Santa Clara County or City of Palo Alto Property Assessed Clean Energy (PACE) program. The conservation-oriented planning of the house allows a 4.2 kW system to meet the zero-net energy goal. One thought is to wait a year to fully gauge the electrical load (including that of an electrical vehicle or two) and then install the system. Note: a tradeoff was made between exterior wall punctures and exterior aesthetics. Also, to reduce the installation cost of future PV, a ¾” EMT conduit runs in the wall from the roof to just next to the main breaker.
We have endeavored to maximize PV generation by locating the house as far from the street trees as the City of Palo Alto would allow. The roof slope necessarily conforms to the City of Palo Alto’s “Daylight Plane” requirements which minimize the house’s shade on neighbors. Despite Planning Department constraints, annual PV generation from this roof is within 1% of that from a theoretically ideal slope and orientation, according to the PVWatts online calculator. www.PVwatts.org
Electrical vehicle charging
Conduit to hold 100amp, 208V wiring to the front driveway will be laid. A similar (40 amp) cable will be at the back of the house for the planned electrical vehicles (A Nissan Leaf is on order to be followed potentially by a Tesla Model S). Some might debate the need for 100amp wiring. This is to future-proof for the potential of some form of home “quick charging” or to be able to “harvest” grid-sourced, inexpensive, intermittent renewable energy such as wind power.
We are not wiring the house with CAT6 or other data wiring (except for phone jacks and cable) with the assumption that the future is wireless and will communicate via ZigBee or Powerline Carrier. If someone feels we are mistaken, now is the time to speak up!
Energy monitoring system
We are going with the TED 5002G and will monitor solar generation plus home energy use and this information will be posted live via Google PowerMeter. Electric vehicle energy use will be monitored via the car and or charge spot. On moving in, we plan on determining the major individual appliance energy use initially then every couple of years via a number of kill-a-watt meters. theenergydetective.com