Is your fridge running up your electric bill? Well you better catch it! Conducting your own home energy audit often shows that it takes a lot of power to keep your food cold, especially if you're using an older model. One way to make sure your refrigerator is running as efficiently as possible is to check that it fastens tightly shut. Here's a simple and quick way to test the seals on your appliance's doors from the California Energy Commission — and all you'll need is one dollar. Take the bill and close the door on half of it, then try to pull it out. If the dollar slides out easily, that means you're probably wasting energy (and money) by letting the cold air leak out. If a new fridge is not in the budget, you can order a replacement seal for most appliances online or from the manufacturer directly.