Smart Meters are the next generation of meters, that communicate your energy usage to utilities, in live time. Allowing you to say goodbye to estimated bills once and for all. It also means you can see how much electricity or gas you are using in live time, so if you fill a full kettle up to make one cup of tea, you will be able to see that it is more efficient to only fill it with water that you need. Smart Meters are a great way of lowering your energy bills by just allowing you to see how much your appliances are actually costing you to use.
A smart meter IHD is what is known commonly as an In Home Display.