The EPA has a nifty household emissions calculator that you can use to determine how much greenhouse gas emissions your household is currently responsible for, ways you can reduce emissions and energy use, and how much money you could save while doing so.
The last part may be particular useful in tough economic times that see house values decreasing while many cost of living factors increase.
Check out this calculator when you get a chance because everyone can play a small role in protecting the environment by reducing their personal greenhouse gas emissions. And don't forget that you'll likely save some money as you do so.