In addition to what has been said here, I wonder what can be said as to the amount of energy it takes to make a building (not to mention to tear down an old building). We sometimes hear criticisms of various proposed alternative fuels and power sources because of the amount of energy it takes to make the fuel or produce the power equipment. (This is much discussed with Solar PV, for example and with ethanol). So, what about houses?
We are spending a lot of effort analyzing how we can make our homes more energy-efficient. How much energy is expended, typically, in building a home (fabricating durable building materials and items, transporting the heavy items to the building site, running the various necessary machines)? Maybe you'd include food for the workers, I don't know. If it's an amount of energy that is substantial enough to equal the amount of energy the home-users might use in 1, 2, 3, 5, 10 years, then this would be interesting. I mean, with solar PV, we hear that the amount of energy it takes to fabricate the panels can be equal to what they will harvest in 1, 2, 3 years. And so we may say that the panels, over their 20-30-year useful lifetime (or however much time) will harvest 7 x more energy than it takes to make them (just to use a number I once heard about one manufacturer's panels). Ok, so what about a house. And if the amount of energy it takes to fabricate is a bit respectable, then mightn't energy be saved by making the expectation that the house (with reasonable upkeep) can last 200 or 300 years rather than 50-100? Other questions of course that sort of add to the point: We can also ask of course if some of the materials can be recycled, then this could lower the house's number at the back end. If wood can be burned or processed when the house is torn down, then this could be useable energy. Another reasonable part of these calculations I think would be if some of the home is built to harvest energy rather than just use it. This is not only what heat it might retain at night, but also if solar panels are installed in some way, micro-hydro, what sort of power requirements are necessitated by the pottable water choices made by the builder, maybe even if some bio-matter processing is somehow built into the design so it's easier for the homeowners to get into biomass use? Last but not least there is distance-to-travel destinations because an occupant's energy use over the lifetime of occupancy is so affected by how much transport fuel she or he may need every day. On Thu, 11 Mar 2004 03:17:09 +0100, you wrote: > >MM, > >Most building codes sets minimum life span for buildings to 50 years. This >to establish a minimum quality demand in legal disputes. This is on >construction, not the installations. Normal renewing of buildings in peace >times are between 1 to 2% of the building stock and therefore it takes 50 >to 100 years to renew the building stock. It will be a remaining small >portion of older buildings, but they are not effecting the average numbers >(the same happens to cars). Renovations and renewal of installations, have >much shorter cycles and then improvements/changes can be introduced. It >seems however to be a large number of more than 50 year old heating >systems, still in use in US. > >Hakan > >At 03:55 11/03/2004, you wrote: >> >The reason for this is quite simple. Though our country's fleet of >> >autos and light trucks could turn over within about 12 years and be >> >replaced by more efficiently run vehicles, buildings have a lifespan >> >(and energy consumption and emissions pattern) of 50 to 100 years. >> >>Something else I want to mention about this article: >> >>If you put $50,000 or $100,000 or $200,000 or more into building a >>home, it should be built to last more than 50 or 100 years, in my >>view. Some here may be able to amend or differ with my view and >>educate me. And there's probably a school of thought in sustainable >>building that it's not necessary to build-to-last. >> >>But building a home (or paying someone to do it and buying it from >>them) is the most trouble many of us go to, to buy a "thing" in our >>lives, and there are different schools of thought, it would seem, on >>how much quality a homebuyer "rates". I've heard that wood quality >>may possibly have declined in some respects, overall. Now, there may >>be a period of transition as home builders learn or re-think new >>methods (such as steel), for various reasons. As buyers become more >>educated, I think if they insist that they rate building quality that >>will last, they can communicate this in their buying decisions? > > > > >Biofuel at Journey to Forever: >http://journeytoforever.org/biofuel.html > >Biofuels list archives: >http://infoarchive.net/sgroup/biofuel/ > >Please do NOT send Unsubscribe messages to the list address. >To unsubscribe, send an email to: >[EMAIL PROTECTED] >Yahoo! Groups Links > > > > > ------------------------ Yahoo! Groups Sponsor ---------------------~--> Buy Ink Cartridges or Refill Kits for your HP, Epson, Canon or Lexmark Printer at MyInks.com. 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