InsideRecuiting has published an article giving lots of insight into how companies are relating to telecommuting:

Workers are affected negatively by long commutes

• New survey by the Urban Land Institute: 69% of the larger companies (those with 100-plus employees) believe a long commute time increases employee stress, but 55% reported a lack of affordable housing near their location
• 76% of workers between 18 and 34 would be at least somewhat likely to make a lateral employment move in exchange for a shorter commute (Harris Interactive)

Telecommuting trends

• 45% of the larger companies offer flextime to reduce commuting time, but just 21% offer telecommuting
• 29% of companies say they plan to use a telecommuting program and will allow workers to telecommute every day, and 16% will allow workers to telecommute one or two days a week. Another 17% said they would consider it, if enough employees requested the option (EE)
• Korn/Ferry survey of 1,320 executives indicated that 61% believe telecommuters are less likely to be promoted, compared to their on-site colleagues. Still, 48% said they would consider a telecommuting arrangement

Impact on Environment, Finance

• IBM (25% of 300,000 workers telecommute) estimates that they save $700 million annually because of telecommuting
• Cisco has cut travel by 20% a year due to videoconferencing (two million miles of travel saved, CO₂ emissions lowered by approximately 10%)
• Sun has flexible policies regarding telework, offers local “drop-in centers” which save employees 90 minutes of commuting time ($63 million and 29,000 tons of CO₂ emissions saved annually)

Read more: Honk If Your Company Loves Telecommuting

There is a popular assumption that telecommuting is good for the environment. The reasoning is that people use lots of energy (primarily fossil fuels) going to and coming back from their offices every day. If people worked at home, then they would not be using this energy. Thus, telecommuting is good for the environment.

Self-professed Luddite Sharon Astyk questions this assumption (in the middle of a longer article asking whether more technology is really improving people’s lives, makes people happier, etc):

But the problem is that all those telecommuters would be buying more and better technology for their homes in order to be able to do the work they normally do at the office, and spending more time overnighting documents, heating their own homes, and doing all sorts of other things. Now it might well turn into a net gain - you never know. But it is worth noting, for example that recent evidence suggests that all of us on our computers are a huge global warming problem - as bad as flying all over the planet.

Well, to address the issue directly, there is at least one study released recently which seems to say that overall, telecommuting will result in a 20% reduction in energy usage. Although Sharon is right in saying that a telecommuter (or more normally, their employer) will tend to buy more equipment for their home-office and will spend more money lighting, heating and cooling their home than they would have had they been at work, it is important to remember that every computer on in the telecommuter’s home office is one less computer on in the business office (likewise with lighting, heating and cooling costs). There is a direct trade-off between the two. The energy savings comes from the personal transportation to work (saving an hour-plus sitting in a car, burning gasoline) that you are not doing.

Though it is appropriate and praiseworthy to question common assumptions regarding energy-savings (as well as assumptions that technology makes people happier, causes less stress, improves the world, etc), in this case, I think that it is not really accurate to say that telecommuting will not contribute to less energy consumption.