Believe it or not, that old refrigerator in your garage is a veritable cash cow.

Last year's American Recovery and Reinvestment Act provided $300 million for what amounts to a Cash for Clunkers program for household appliances. Trade in your old appliance for a new, Energy Star-qualified one and receive a rebate. The news cheered manufacturers, whose sales rose 1.2% in January but were still down 7.6% compared with the previous year in 2009, according to the National Retail Federation. Most jumped in with offers to lure consumers. But as dozens of states prepare to adopt the programs in coming months, evaluate carefully before you head to the mall.

For one thing, if you ve recently purchased a new refrigerator, stove, dishwasher or other item, it might not be worth the expense to trade up again. Also, even if you are getting a rebate, you will may have to pay for things like delivery, installation and haul-away costs.

On the other hand, if you know you need say, a new boiler or air conditioner, you should act quickly. "Some states' programs have closed already," says Maria Vargas, a spokeswoman for the government's Energy Star program. Minnesota, for example, started its $5 million program March 1, and blew through its funds for the $50 to $200 rebates on clothes washers, dishwashers, freezers and refrigerators by March 2. Iowa ran through its allotted $2.8 million in rebates on March 1 the same day it began offering them. (The rebates covered 13 products and ranged from $100 to $500.)

Use these six points to decide if you should trade in:

Assess need

Not sure if you're due for an upgrade? Rebates don't require your old appliance to be a certain age, but you'll get more bang for your buck if it's a dinosaur. "There are fairly constant improvements to energy efficiency," says Lowell Ungar, the director of policy for the Alliance to Save Energy. Any new model, Energy Star qualified or not, guzzles less energy than a 10-year-old refrigerator or clothes washer. But a new appliance is a major expense, so don't shell out if the item is relatively new or still functions like it is.

Read the fine print

Each state has its own list of qualifying items as well as efficiency and purchase criteria. Check your state's program site for the fine print and rebate availability before you buy. Georgia, for example, excludes purchases made online. New Jersey covers 14 items including refrigerators, clothes washers and dishwashers, while Indiana includes just boilers, air conditioners, furnaces and heat pumps. And Michigan offers $25 for any Energy Star dishwasher, but will double that to $50 if the model meets specific water and energy-use requirements.

Hunt for sales

Although sales at electronics and appliance stores rose 1.2% from December to January, they are still down compared with the previous year. Retailers and manufacturers are eager to catch shoppers' eye, offering mail-in rebates and big sales. For example, Whirlpool is offering $50 to $200 on select Energy Star-qualified Kitchen Aid dishwashers and refrigerators purchased before March 21.

When comparing prices, factor in delivery, installation and haul-away costs, says Dale Haines, the senior director of the real estate and construction industries practice at J.D. Power and Associates, which offers annual ratings of appliance retailers. "Appliance retailers have some flexibility on pricing," he says. If you're not up for haggling, most will at least match competitors' prices or offer to refund the difference if you spot a better deal soon after your purchase.

Recycle

Properly disposing of your old appliance gets you extra cash in some states. Illinois, for example, offers an extra $100 for refrigerators and freezers with proof of recycling, and an extra $50 for dishwashers and clothes washers. (Many appliance retailers offer free haul-away and provide documentation of disposal.)

But the biggest financial incentive for prompt disposal is your energy bill. "If you buy a new energy-efficient refrigerator but keep your old one running out in the garage, it's not using less energy it's using more," Ungar says. "The savings comes from getting rid of the old, less-efficient item." Energy Star refrigerators must be 20% more efficient than the standard versions, saving you an estimated $165 over the life of the fridge.

Check utility rebates

Your electric or gas provider may also offer incentives for buying an energy-efficient appliance. Kansas City consumers who purchase a qualified boiler before the end of December can get an extra $200 from Missouri Gas Energy. Most states are coordinating with utilities so that there's no double dipping, Vargas says. Utility rebates may be for items the state won't cover, or have slightly different qualifications so that consumers must buy an even more efficient product to get the extra money.

Depending on what you buy, your purchase may also earn you break come April 2011. Select improvements put in place before Dec. 31 qualify for a federal tax credit worth up to $1,500. Replacing a water heater, for example, can net a credit worth 30% (up to $1,500) of the purchase price.

Other tax breaks are more immediate. Missouri is hosting a sales tax holiday on Energy Star products up to $1,500 from April 19-25. Texas will host one from May 29-31 on Energy Star air conditioners up to $6,000 and other qualifying products up to $2,000. (If you can't take advantage of the rebate program now, North Carolina, Virginia and West Virginia also plan to host Energy Star tax holidays during the fall.)