Smart controls are a way to manage your heating & hot water timings and give a more accurate room temperature than a mechanical thermostat.  They are Wi-Fi enabled which allows you to alter your thermostat temperature or on/off times whilst away from your home. This gives you more control over when your boiler is actually heating your home, which means you can use less gas.

Different brands will come with a variety of different features, but thing such as multi zone support, geofencing and voice enabled support (for Amazon Echo, Google Home etc) are common.