Plastic can surely help reduce any unwanted loss of heat. Purchase a window insulation kit at your local hardware. Window plastic that has been properly installed can appear invisible.
Allowing the suns rays to filter into your windows during the day will warm the air. But be wise to close your curtains or blinds in the evening to aid in holding onto the heated air.
Putting that caulk gun to good use now will pay off during the winter season. Start protecting your home by mending any cracks around your window frames and doors on the both inside and outside of your home. Pay close attention to corners, around chimneys, where pipes or wires exit and along the foundation. There are easy ways of identifying air leaking into your home. Either use a stick of smoking incense carefully and move along walls or on the outside; use a hair dryer around each window while you hold a lit candle inside. Where the smoke wavers, you have identified an air leak. Wood filler can be use to fill in gaps between the wood siding and the window frames. For extra protection, paint over the wood filler with a weatherproof primer and exterior paint.
An alternative to caulking is to use weather-stripping. Vinyl Weather-stripping your windows is important for keeping your home insulated during the winter and is an effective solution for around $5.