Install Storm Doors and Windows

The simple act of installing a storm door can increase energy efficiency by 45%, by sealing drafts and reducing air flow. Storm doors also offer greater flexibility for letting light and ventilation enter your home. Look for Energy Star-certified models.

Similarly, storm windows can make a huge difference when the cold wind starts blowing. It may be a pain, but it is well worth it to get them out of the shed or attic and install them for the season. (Make sure each is securely shut -- they don't do much good if you leave them in the up position by mistake!)

Efficient doors, windows and skylights qualify for a federal tax credit covering 30% of the cost, up to $1,500.