What is a Zero Carbon Home?
In response to our post Crossway Zero Carbon Home Brings Back the Timbrel Vault, commenter rayn wrote: "I don't see how this house could be anywhere near zero carbon even if all the bricks were sun baked. The windows had to be created in a furnace somewhere."
He has a point. "Zero Carbon Home" is a term with specific meaning in the UK:
A zero carbon home is one that generates as much power as it uses over the course of a year and therefore has net zero carbon dioxide emissions.
It has nothing to do with the amount of carbon embedded in the construction of the house, so one could theoretically build it out of insulated concrete forms, one of the most carbon and fossil fuel intensive forms of construction, and still qualify.
This is Money describes the process of building a zero carbon home this way:
RuralZED: UK's First Commercially Viable Zero-Carbon Home : TreeHuggerAll New Homes in the UK Will Be Carbon-Neutral by 2016 (?)First Zero-Carbon House in UK UnveiledZero Carbon House in Scotland
A zero-carbon home is one that returns to the National Grid as much power as it uses over the course of a year. Unless you plan on living somewhere with no heating, electricity or water, that means a zero-carbon home will need to be kitted out with equipment for microgeneration – the production of energy on a small scale.
So, in come mini-wind turbines, solar panels and a wood pellet burner for generating energy. Meanwhile, to keep that precious energy in you will need clever, draught excluding construction with super-insulated walls, a geothermal heating system extracting heat from the ground and triple-glazed windows. You might also want a rain water collecting tank to supply the washing machine and lavatories and to be connected to a reed-bed sewage system for organically cleaning human waste.