New ones are twice as efficient or more. For fridges: if they’re old an upgrade can pay for itself in as little as three years in energy savings alone. Look for the Energy Star label when you shop for a new fridge or any other appliance, especially freezers, furnaces, air conditioners, and water heaters, which use the most energy). These items may cost a bit more initially, but the energy savings will pay back the extra investment within a couple of years.