The latter supplies power from the grid when the occupants are using more electricity than is being produced by the solar panels mounted behind the house, and exports at times of surplus generation.
The other is the Hockerton Housing Project, five one-story residential units using the same design tactic of thick walls, thermal mass, and superinsulation.
[5] Among their research claims is that a medium-sized pet dog has twice the carbon footprint of SUV driven 10,000 kilometres (6,000 miles) per year, based on the estimated energy impact of food production and waste generation.
[5][6] In addition to carbon footprints, they analyse several popular types of pets with respect to their impacts on wildlife populations, spread of disease, and pollution.
[10] The book looks at vintage sets of Lego, Meccano, Lincoln Logs, and more obscure products in the context of teaching concepts such as modularity and load-bearing construction.