So many guides to saving energy tell you what to do; they might say insulate your walls or change your windows, but they don't tell you what the cost-effectiveness of each action really is. That's why we love the Cool Citizens Guide from the Rocky Mountain Institute; it not only advised what to do but determined the cost in dollars per ton of carbon dioxide saved so that you can decide which action is most effective for you.

As an example, changing your windows is really expensive relative to the amount of carbon saved, coming out at $133.88 per ton of carbon saved, whereas changing to a programmable thermostat is relatively cheap to do but yields big results, coming in at $ 9.34 per ton of carbon saved. Given how much energy prices have risen in the last five years, these numbers are low but the relative relationship is what's important. Of course, the best things in life are free, so we will start with those:Household Carbon Emissions:

1. Lower water heater temperature to 120°F

2. Increase AC thermostat by 3°F

3. Wash clothes in cold water

4. Air dry clothes during summer

5. Turn off unneeded lights

Just taking these free actions will save 1600 pounds of carbon per year. Download the PDF at ::Rocky Mountain Institute

Difficulty level: Easy