Smart appliances are specialised equipment programmed to run from a central system. Any domestic device can be a smart appliance.
They have an added benefit where sometimes they can be hooked up to the manufacturer as well, so when there is a problem you can get an immediate notice of the problem and estimate of the repair.
These Smart Appliances can sense an electrical surge and can shut off their own power. They can sense a water failure and turn off the mains. They know when they need defrosting, they know how long to cook your meals and some can even keep track of expiration dates or can create recipes based on the ingredients in the cupboard. Your house will know when it is raining and close the windows for you, even while you are away. However, the most fascinating aspect of smart homes is that the possibilities are completely limitless because you can now actually communicate with your house.