Number of the Day: 300
by Collin Dunn, Corvallis, OR, USA on 08.28.07

300 -- the percent by which real estate and construction professionals overestimate the costs of green building, according to a study by the World Business Council for Sustainable Development. [pdf]
5 -- the actual cost premium, in as a percentage, for green building. Further...
19 -- the percent of greenhouse gases emitted by buildings, according to survey respondents.
40 -- the actual percent of greenhouse gases emitted by buildings.
That's right: industry folks overestimate the costs of going green(er) and underestimate the damage being done. As Dave at Gristmill notes, all we need is some proper education to turn it around. ::World Business Council for Sustainable Development via ::Gristmill
[Update: We should note that the WBCSD is a guest author here at TreeHugger (the most recent post is here). Stay tuned for more of their great posts, coming soon!]


















Does anyone know the actual percent that is required to make a building green?
It would be nice to tell people it only takes x percent more to build a house using green alternatives....!
**Author's comments**
UncleBen,
Thanks for your note; I've updated the post to reflect your request (it was a good one!). Would you believe that the cost premium is only 5%?
-CD
actually, once you get over the learning curve, you can build green with no cost premium. It's a matter of budget shifting - ie. you may spend more on insulation while saving on HVAC.
5% added cost, that sounds optimistic. Or maybe it depends on your construction methods. Here (Belgium) you must count about a 10% premium.
But the most astonishing is the 40% of greenhouse gases emitted by buildings. That seems like an awful lot Are there sources for this? Looking quickly at the provided links, I found that buildings are responsible for 40% of energy use, according to the WBCSD report.
First, what is a building? Residential? Commercial? Industrial? It seems that the report considers it's the first two. Also, energy use and greenhouse gas emissions, while linked, are not synonymous.
I found this on Wikipedia:
http://en.wikipedia.org/wiki/Image:Greenhouse_Gas_by_Sector.png
According to that chart, residential + commercial + other sources (!) only amount to 10.3%. Even adding the whole 21.3% for power station emissions (which, we'll agree, is not fair) that only amounts to less than 32%. So I'm curious, how can one reach an amount of 40%?
Depending on what you mean by gases emitted by buildings, you can produce very different figures, from less than 10% to 40% or perhaps more. All in all, 40% seems like a stretch and the popular guess of 19% might actually be a fairer figure.
Also (to add to my previous comment), it must be noted that the Wikipedia chart only shows man-made greenhouse gas emissions. Also to note: the chart applies to year 2000.
40% does sound off. Considering how much time we in THE WEST (emphasis placed to highlight why cited wikipedia numbers are off) spend in buildings constantly using energy for all manner of things, 40 sounds low to me.
The actual costs of being green vary, just according to how many green features, and what materials will be used. Either side can make a case based on almost any percentages. Also, it makes a difference whether "Actual cost" includes government subsidies, which might themselves be thirty percent of project cost or more. So, this is really just a silly, meaningless bit of agitprop.
Most of the changes described are very expensive changes, like heating, going from mid-efficiency to very high efficiency can double the cost of that system. Conventional roofing systems are well understood, planting on the roof adds a lot of cost and risk. specifying complex and uncommon light fixtures results in higher cost to buy and more labour to install. Not to mention getting local authorities to sign off on different methods of building.
and, sorry to burst the bubble but if it only cost 5% more people would already be doing it, because then it would be justified by the cost savings,...