A freak winter storm in January dumped several inches of rain over a two-week period and one morning we woke up to an even more rare dusting of snow that covered the cacti and the mesquites. The solar electricity system failed miserably, along with the solar water heater, because of the lack of sun and design miscalculations. We were forced to borrow and then buy an electric generator and light up the propane water heaters. The array of windows on the south and east sides of the house, which were supposed to trap sunlight to warm the interior instead leaked cold air and even trickles of water. A basement storage room underneath the kitchen flooded. Indeed, the only thing that seemed to work properly was our huge rainwater collection tank which filled up in two or three days.
For a couple of years Stew and I had planned an off-the-grid, self-sustaining house, studying scores of books on everything from xeriscaping to wind generation of electricity, poring through magazines and websites, and quizzing people for experiences or suggestions.
Real-life stories were surprisingly unhelpful. Some of the folks living in green houses in San Miguel were a bit too green for us. Shoveling composting toilets, for instance, was never in our vision. Even close friends reacted with polite, puzzled or amused looks: "Now, why would you want to do that?" or "Hmm, isn't that a little far out?"
More helpful than anyone was our architect, who not only was open to new ideas but also incorporated several excellent design features of his own. Most if not all of the other architects or builders we interviewed were thoroughly ignorant about green construction and a few were downright hostile to the concept, laughing it off as some lame-brained gringo fad that would go away.
Now that we've lived here over three years—ready or not, we moved in on Christmas 2009—we are happy to report that after the initial shakedown period, and additional tweaking, we are delighted with the results. The greatest reassurance about our decisions comes when we visit other homes in San Miguel and the surrounding countryside: Although many are bigger or fancier, we still haven't found one that we like better than our own.
|All's well that ends well: The final product.|
The house is definitely off the grid except for propane delivered by truck for cooking and heating, and water from a community well that arrives (anemically and erratically) twice a week for four or five hours each day.
For all other modern amenities—the bulk of the water supply, electricity, telephone and internet (both wireless), sewer, heating (mostly passive solar) and even access (through a half-mile-long dirt road), the house stands on its own on seven-and-a-half acres, on a small hill surrounded by mountains and farming and grazing fields.
1. Location, location
Our house in many regards has a unique location, which like most locations involves both good and troublesome news. According to Google Earth, we live at an altitude of sixty-nine-hundred feet above sea level. Not Mt. McKinley but a good ways up in the air. By car, the nearest towns are San Miguel de Allende (pop. 85,000 and about thirty minutes away); Querétaro (pop. one million and one hour away); and Mexico City (pop. several bazillions and four hours by bus). We're almost equidistant from both coasts and about ten hours by car (with a tailwind and not too many police checkpoints) from the U.S. border at Laredo, Texas.
Sunlight is plentiful in this semi-desert terrain, in fact about three-hundred-and-thirty days of it annually. Even when the day starts out gloomy or iffy, the sun dominates by eleven o'clock or noon. That means that even if the temperature drops below freezing overnight, which generally occurs only three or four times a year, by noon we're back to light-jacket or short-sleeve weather.
I have no data on winds and haven't found any wind maps for this area, but it feels unusually windy here, much more so than the reputedly windy city of Chicago. Even when days start out calm, the wind often kicks up, along with the dust during the dry season, and can reach ten or twelve miles an hour by late afternoon, dying down along with the sunset.
This all adds up to a climate well suited for both passive and active solar energy rigs. That yields very low cooling and heating bills and quick paybacks on solar equipment, provided that the house is oriented and designed appropriately. We've seen many stupidly built houses here that defeat the solar advantages of this area.
So far so good, except for one major hitch: Scarcity of water. We normally get approximately twenty inches of rain a year, far drier than Chicago or Miami, but much wetter than Arizona, New Mexico or southern California, all of which get along on single-digit annual levels of precipitation.
Our rainfall, however, would be much more beneficial if it were spread throughout the year. Instead it rains heavily between July and October, when the hues of the landscape go to bright green from the beige/browns that dominate the rest of the year.
Sinking private wells is quite expensive and licenses are difficult to obtain, hence our decision to incorporate a thirty-five-thousand gallon rainwater reservoir under the terrace. Aquifer levels reportedly drop every year and some wells have shown contamination by heavy metals and other pollutants. A drought along the Mexican-U.S. border for the past two years doesn't help our worries. Availability of water is bound to be a challenge in this area for the foreseeable future.
Temperatures are mild with a couple of exceptions. It can get brisk at night during the winter (January and February) and hot during the summer (April and May). Yesterday it was ninety-five degrees at two o'clock in the afternoon, with a ambient humidity of seven percent—that's right, 7 percent—though it gets much more humid once the rains start.
The ubiquitous wind can work for or against you. In winter it can whistle past the weatherproofing on the windows and doors and make it feel clammy inside after the sun sets, but the during the summer, combined with the low humidity, it makes ninety degree-plus days seem quite pleasant.
If there's one thing we've learned about green construction is that all factors play off with or against each other. If the exposure and windows of the house are not calculated properly—one rental in which we lived before moving here had cathedral-size windows that faced straight west, which made the place an oven in the afternoon—it's going to be difficult to maintain comfortable temperatures inside and will pose an insurmountable challenge to a solar electric system. Likewise very high ceilings make the spaces below difficult to heat.
Generally our house performs admirably in all seasons, though there have been a few goof-ups along the way that I won't be too shy or proud to discuss. I'll be happy to answer any questions or comments.
Next post: Orientation and construction materials