When you choose a freezer, remember it's probably going to be with you for a long time. So it's important to know which freezer is right for your needs.    First, decide if you want an upright or chest model. Uprights are more convenient. Their storage space is more accessible and they take up less floor area. However, chest models are more energy-efficient because less cold air escapes when they are open.    If you are buying an upright, you'll have to choose between frostless  or manual  defrost . Chest freezers are always manual. Frostless freezers automatically defrost at present intervals  and remove the water. Manual models must be defrosted by hand every few months or whenever frost pile up to about a quarter of an inch.    To help your freezer reach a ripe old age, try to find a spot that's cool, dry, and away fromdrafts . Drafts and heat will raise the freezer's cabinet temperature, which makes it work harder to keep cool. That means wasted energy. That means wasted energy and a shortened life.    Dry air is important because highhumidity  can cause the freezer to rust outside and frost up inside. With proper care, a freezer can serve you for 15 years or more. Regular cleaning and simple maintenance will help it maintain a zero-degree temperature and keep it smelling fresh and looking almost new.    Frostless models requires less care than manual defrost freezers. The inside of a frostless unit should be washed periodically with warm water and baking soda or a mild soap, rinse, and dried.   Good habits go a long way toward a freezer that runs efficiently. To get the most from your freezer, check regularly to make sure it's providing a true zero-degree temperature.   Keep the freezer at least three-quarters full. The emptier it get, the more energy is wasted. If more than three pounds of food per cubic foot of storage space is added every 24 hours, the resulting high or low temperature can damage the food. Which statement best describes the main idea of the passage?
It tells the most economical ways to use a freezer. It explains how to defrost a manual-defrosted freezer. It introduces the advantages and disadvantages of two kinds of freezers/ It gives useful advice on how to choose and maintain a freezer.