Want to know if your home is using too much energy compared to homes that are similar in size in your part of the country? You can hire an auditor to come and analyze it for a fee, or you can do it yourself for free with help from the Environmental Protection Agency's Home Energy Yardstick. All you need to know is your ZIP code, square footage of your house, number of occupants, types of energy sources (electricity, gas, etc.) and have the last 12 months of utility bills for the house (which you can also get from your utility companies). The online tutorial will take you through the process, and it'll give you an audit score. It will also give you information on how much energy you use for heating and cooling, cooking, lighting and hot water. Plus, it provides tips to lower your bills, improve comfort and increase your home's score. Do it at energystar.gov.

When traveling abroad -- or if you're just not sure if the tap water in your home is safe (perhaps there was an outage, your filters are out of date or it just looks suspect) -- consider boiling it. It's the cheapest, fastest and most effective way to purify water and remove harmful pathogens and bacteria. And it's simple: Just fill a teakettle with cold tap water and bring it to a boil for one minute. Remove it from heat and allow it to cool. Even in countries where drinking tap water can be questionable, this method is one foolproof way to purify water.

When it comes to choosing a shower curtain, a nylon one is the greenest and easiest choice. Unlike fabric curtains that need a plastic liner, nylon curtains are naturally water-resistant and do not need a second liner. But they are also greener because they don't off-gas the way old-fashioned PVC shower curtains do. Even better: Unlike PVC, which is not recyclable, nylon shower curtains are recyclable and can be made into new products, like carpeting, string and fabric.