The Sustainable Home Blog

“It has often been said that, if the human species fails to make a go of it here on the Earth, some other species will take over the running. In the sense of developing intelligence this is not correct. We have or soon will have, exhausted the necessary physical prerequisites so far as this planet is concerned. With coal gone, oil gone, high-grade metallic ores gone, no species however competent can make the long climb from primitive conditions to high-level technology.
This is a one-shot affair. If we fail, this planetary system fails so far as intelligence is concerned. The same will be true of other planetary systems.On each of them there will be one chance, and one chance only.”
Sir Frederic Hoyle, British Astronomer, 1964

Hoyle’s “necessary physical prerequisites” are not yet gone, but the extraction of our most critical non-renewable energy resources will soon reach a geological milestone, and production will peak and then decline. This will set a two to three decade clock on our last and only chance to achieve a sustainable society.

• The consensus is that the production of oil has already peaked (2006) or will peak shortly and that serious shortages will occur by about 2010
• Natural gas production in N. America will peak between 2010 and 2015
• Uranium extraction will peak in 2025 and shortages are possible as early as 2013 when we can no longer depend on the recycling of Russian nuclear warheads to meet demand.
• Coal will peak around 2025 at about 30% above the present production

“…we don’t have to run out of oil to start having severe problems with industrial civilization and its dependent systems. We only have to slip over the all-time production peak and begin a slide down the arc of steady depletion.”
Howard Kunster ,The Long Emergency, 2005

We are left with the choice of only two future paths of development. The “business as usual” path will lead us to tragically overshoot the earth’s carrying capacity, resulting in economic collapse, and a dramatic reduction in the earth’s population as we return to a pre-industrial revolution standard of living. The second path represents Hoyle’s “last and only chance” to wisely use our remaining fossil fuel resources to build a sustainable and renewable energy foundation for a new steady-state world economy. An economy and society with a stable population that falls within the limits of our planet’s carrying capacity. I fear that the greater probability lies with the first path, but know we have both the knowledge and means to forge the second.

On the supply side, the second path requires that we rapidly replace our current extractive, non-renewable energy model with renewable sources like geothermal, solar, wind, and wave power. It will be a future dominated by electrical power as liquid fuels become increasingly scarce. However, it will not be enough to reach a stable, sustainable future without major changes to the demand side of the energy equation.

As we enter this period of sustained crisis and begin the journey down the path of ecological stability, it will quickly become evident that the only reasonable standard for building design will be a standard of net zero energy consumption. Because we lack information, initially this will be part science and part intuition based on passive heating and cooling lessons from the past. Eventually we will come to know the embodied energy of every building material and component and make many decisions based on the EROIE (energy return on investment of the energy embodied) of building products like insulation, low-e glazing, PV panels, and wind turbines. Houses will become smaller and change shape as energy trumps fashion and becomes the primary design factor. A whole new industry will emerge to help homeowners convert over 100-million thinly insulated, poorly constructed homes into some semblance of energy efficiency. Pattern’s of development and zoning laws will change as the age of the automobile comes to a close. Populations will shift and migrate as the end of cheap air-conditioning makes living in many parts of the country less desirable. Home landscaping will change from ornamental to edible, and grey water irrigation will become commonplace as the energy costs to move and purify water change our attitudes about this precious natural resource. Local materials will dominate construction and the age of imported italian granite countertops will come to an end.

The longer policy makers wait to take action the lower the probability of success. When shortages become evident we may still fall into denial. Demagogues and special interests will deny the limits of geology and blame OPEC, Islam, environmentalists, or speculators. If allowed, they will cloud the issue and cost us precious time.

Our “last chance” will be a battle. It will not be an easy time.

Low-e glass, first introduced in 1979, has transformed window energy performance. Low-e glass is manufactured with a microscopically thin and transparent layer of metal or metal oxide that reflects infrared “heat” energy back into the home, greatly enhancing the thermal performance of the window.

In the simplest of terms, there are basically two kinds of Low-e glass:

1. Low-e glass with a low Solar Heat Gain Coefficient (SHGC) that also reflects and keeps much of the Sun’s heat energy out of the home. This is the best choice in climates dominated by cooling.
2. Low-e glass with a high Solar Heat Gain Coefficient (SHGC) that allows the Sun’s heat energy into the home. This is the best choice in climates dominated by heating or for south facing windows in climates with a mix of cooling and heating requirements.

All this seems pretty straight forward until you actually attempt to purchase a window with Low-e glass. But before I get into that let’s take a look at the climate zones in the U.S. used by Energy Star to determine the qualification criteria for windows and skylights in an Energy Star rated home.

The Northern zone is the perfect candidate for a Low-e glass with a high SHGC and the North/Central and even the South/Central can greatly benefit from high SHGC Low-e glass on southern exposures. Unfortunately, even though the average American family spends far more on heating than air conditioning, both Energy Star, LEED, and the International Energy Conservation Code (IECC) seem to be color blind when it comes to space heating and the benefits of Low-e glass with a high SHGC.

Energy Star requirements for SHGC seem to be all about cooling as the following requirements for SHGC for each climate zone indicates. The IECC is no better, only requiring a SHGC of ≤ 0.40 for any residence with less than 3,500 Heating Degree Days (HDD). LEED only takes the cooling bias further by requiring even lower SHGC’s in the South/Central and Southern climate zones.

As an unintended consequence of the regulatory bias in favor of cooling, window manufacturers have all but abandoned Low-e glass with high SHGC’s. The result is a nation divided, with more than half of the country left out in the cold without ready access to high performance windows that take advantage of the free solar energy that strikes our windows everyday. With very few exceptions you just cannot find a window manufacturer willing to give you the glass options we need and require in heating dominated climates.

So what’s the consequence of the current regulatory bias? First of all it makes no sense, according to the U.S. Energy Information Administration’s (EIA) 2001 Residential Energy Consumption Survey, Americans consume more than 7 times more energy for space heating than for air conditioning. To get an estimate of what’s on the table for high SHGC, Low-e glass in terms of the potential energy savings I assumed a 10% improvement in heating costs for homes in the U.S. with more than 4,000 Heating Degrees Days. Based on the same 2001 EIA Survey, that would amount to an annual savings of 0.362 quadrillion(1 followed by 15 zeros) Btu’s per year or in monetary terms, about $475 billion dollars worth of natural gas!

When the government gets serious about Global Warming maybe they’ll fix the cooling bias in the regulations, but until then here’s where to go to get a Low-e windows with a high SHGC:

• Accurate Dorwin, Manitoba, Canada
• Alpen Windows, Boulder, CO
• Fibertec Windows, Ontario, Canada
• Thermotech Windows, Ontario, Canada
• INLINE Fiberglass, Ltd., Ontario, Canada
• Marvin Windows & Doors, Warrroad, MN (you will need to call their technical support for architects and design professionals @ 1-800-346-3363 and ask to specify your own glass)

Just want a source for the glass? Try Pilkington North America.