However, also from the Times, "California reports that it has reduced energy consumption in new houses and commercial buildings by 75 percent over the three decades that codes have been in effect there." (A New Enforcer in Buildings, the Energy Inspector ).
So, if we age in our existing homes, how much damage are we doing to the environment? People who have just paid off their 30-year mortgage on a house built in the late 70s (or worse, the 50s or 60s) are using, on the basis of the California claim, 4 times the energy they would in a new building. Assume they have two or three times the space they really need, as well, and the inefficiency numbers go higher. Of course, if they were to downsize and sell the house—to a young family, say, who might need the extra space, the building's energy inefficiency would not change.
Back on the plus side, the embedded energy in our existing buildings (the energy it took to harvest, manufacture, transport, and construct them) gives preserving them an advantage over abandonment or demolition (using more energy) and replacement with new construction (embedding more energy again).
So how can we weigh all of the capital and operating numbers to minimize carbon emissions while accomplishing other goals (aging in place, preservation of older architecture)? With all of the news of foreclosures and virtual ghost towns of housing developments, the Times also reports "Construction starts on single-family homes... increased 14 percent for the biggest rise since December 2004" (Housing Starts Rise an Unexpected 3.6%), is there a comparable surge in renovation coming out of the stimulus funding?
One approach at the grassroots level is reduction of household carbon footprint. First we can take actions that make older houses more energy efficient in their infrastructure (insulation, windows and doors, plugging leaks) and systems (methods of heating/cooling, lighting, hot water, appliances). These actions will not get us to the energy efficiency of new construction, but when embedded energy is considered, they can cut the difference down to pretty reasonable numbers.
Then we can take additional lifestyle actions that further reduce our footprints to the extent that the percentage differences between good new construction and upgraded existing buildings involve much lower absolute emission numbers. These include home energy practices (the way we use heating/cooling, lighting, hot water, appliances [including electronics]) and lifestyle practices (how we travel, eat, recycle, buy or collect energy).
All this can seem a pretty daunting individual agenda, which brings me to the final point of this post. The Newton Eco-Team Project, of which I am an organizer, is part of a multi-community initiative in Massachusetts to reduce the household carbon footprint by 25%. It combines global warming education, saving money through reduced energy consumption, and building community through working together and sharing ideas. Altogether home improvement. Our website, which will offer resources identified and/or developed by all of the communities involved, is just now being created, at www.NewtonEcoTeams.org. It should be live by next week.