energy conservation

Mother Earth is getting a little bit of relief as more companies yield to pressure from environmentalists and activist shareholders to reduce their carbon footprints. But Gaia isn't the only one who's benefiting: Just ask some of the companies that have saved serious greenbacks by going green.

Cutting energy use in buildings -- both commercial and residential -- is a hot market for a growing number of tech companies, from giants such as GE and Intel to Silicon Valley startups. And the federal government is an eager booster.

Cisco is expanding its foray into the smart grid with plans to acquire Arch Rock. The San Francisco-based startup is developing wireless-networking equipment for the electrical grid.

EMeter, which makes software that monitors energy use, is the latest smart-grid tech startup to garner significant investment -- $12.5 million worth. With old electricity grids being replaced with smart ones, investors -- and tech giants like Google and Cisco -- are surging into the sector.

As part of the American Recovery and Reinvestment Act of 2009 recently signed into law, there are several energy conservation incentives for homeowners, including a never better opportunity to install energy-efficient replacement windows. There are lots of good reasons to consider replacing...