One large pollutant in our house design is in the foundation. We ended up pouring around 13 yards of concrete due to the large elevation change from North to South. If the site was more flat, we could have used far less. 13 yards of concrete comes out to about 10 cubic meters and a similar carbon footprint to 2 months worth of electricity use of an average US household [1,2,3] or a bit more than a years worth of electricity for a very efficient house like we are hoping to achieve. That is a pretty significant source of pollutant.
We could have used less concrete if we had steped our foundation down with the slope of the building site and put 2 or 3 levels on our first floor, as our neighbor Danny is planning to do. We could have also chosen a more flat building site, or used a different construction method which used piers instead of a solid foundation around the perimeter. On the plus side, using a rubble trench foundation instead of a slab (as most homes are built these days) saved meant we used 3 times less concrete than that method would have required.
Admittedly CO2 emissions aren’t the only thing poluting the atmospehere so a comparison between electricity and concrete curing isn’t really fair. Coal emits lots of other nasty things and cement used in concrete can too, depending on the purity of the ore in use. It is difficult to find hard data about the pollutants from each and they differ from plant to plant.
This has made me want to do a carbon footprint analysis of our entire house to see how it all compares. I’ve already done it with some things … to be continued
See Also: The Carbon Footprint of Plastic
cubic foot of concrete → 9.56 kg co2 → 25.8 kwhr → 88000 BTU of electric heat
coal co2 emissions: 0.37 kg / kwhr