Best answer by
Great question, @rob1420
You can use the 'boost' option on either the smart meter or In Home Display (IHD).
By pressing it, you boost the appliance that's connected to the 5th terminal of the meter. For example, storage heaters or underfloor heating. The option is for people that want to boost the heating for 60 minutes during the day as opposed to waiting for the off peak time.