It was a cool Wednesday morning. There was a fresh sprinkling of snow on the Topa Topas from yesterday's storm, but the day dawned clear. Leaving the house I saw the waning crescent moon rise over the east ridge that throws a protective arm around much of the property. The cold air that rolled down these slopes through the early hours of the morning had settled on the meadow leaving patches of ground frost.
It wasn't a hard frost. There was no ice on the puddles.
We had heard the steady thrum of the heat pump compressor in moments of wakefulness through the night. The nights are quiet here: there is the occasional chorus of coyotes squabbling over a kill, the creaking of metal studs as they contract and, when the temperature of the house hits 64 degrees there's that faint thrum. It doesn't happen very often, and mostly not until 3 or 4 in the morning. But Tuesday had been drab and rainy and passive solar - which we rely on to augment our electric heat, only works when there's sun or, to paraphrase Fleetwood Mac, heat gain only happens when it's shining.
We use the most simple minded passive solar strategy. The house is oriented due south and there are 48 feet of 8 foot high windows that allow the low winter sun to warm the monolithic concrete floor of the house. It is a passive radiant floor system - the heat stored during the warmth of the day is radiated during the cool of the night.
In creating what we hope will be a net zero energy house we knew that it needed to be all-electric. In the 1950's and 60's all-electric was an indicator of modernity and cleanliness - the messy reality of remote smoke spewing coal power plants was conveniently expunged from our mid-century imaginations. While we know now that it is more 'efficient' and certainly cheaper to use fossil fuels directly in the heating of our homes, domestic photo-voltaic power generation has dramatically changed this calculus. The inefficiencies of the heat pump are forgiven, the digital calibration of the electric induction cook top is embraced (despite a nagging nostalgia for the analog gas flame) and that gas starter for the open fire is replaced by a store of kindling. There's no way to offset gas or oil usage - fossil fuels are a zero sum game: you use it you lose it. Photo voltaics, however, in the net-metered grid tied system that we use, directly replace grid generated power. (As of January 1, 2010 the Utilty is mandated to pay the homeowner for any net excess fed into the grid over a twelve month period).
The water heater uses an electric immersion coil and, because of the limitations of the California Code of Regulations (CCR), Title 24, which mandates residential energy performance but does not recognize photo-voltaic offsets, we were required to install solar thermal panels which use glycol as a transmission agent with a heat exchange coil located in the hot water tank. With the solar boost the tank races to 140 degrees. Absent sun, it is limited to 120. We notice in the mornings.
The showers had cleared out by early evening on Tuesday and left a sparkling night sky. A few lingering clouds would have served as insulation, but instead, the meagre warmth of the day ascended into the night. On the east coast there was talk of massive snow falls. Here, in Upper Ojai we are attuned to the nuances of our mostly benign climate.
Living at the ragged edge of net zero energy, where warmth is carefully harvested and cooling breezes assiduously orchestrated our house amplifies the comparatively mild vicissitudes of the climate: it becomes a conversation partner in our chats about the weather.