A 6,000 sq ft-8,000 sq ft house is a climate change disaster. If the country doesn't rein in the construction of these mansions the message to individuals is that they're encouraged to follow their urges. The phenomenon with McMansions is similar to that with SUVs: they express a certain sort of success, they're available and they're fun. If legislative folks don't take some kind of position on mansionisation, it will go unchecked.
Compared with modest size houses of perhaps 2,000 square feet McMansions of 6,000 to 8,000 square feet take more energy to heat in the winter and cool in the summer. Also, there is a lot more space to light and more room for all those energy using appliances such as TVs and computers. With about half of electricity being generated with coal burning in the United States it is not hard to see why McMansion building is another driver of global warming.
The article points out that there are places that are starting to take action to halt this madness. For example, Boulder, Colorado, the first city in the US with a carbon tax, has imposed a cap on the size of new house after the average size new house grew to over 6,000 square feet.
The excesses in American society seem endless. Limiting house size might be a good place to start attacking the bigger is better problem. Bigger isn't better because our planet isn't getting any larger.