Paul Massara said the actual unit prices of gas and electricity in the UK are among the lowest in Europe, but bills were high "because British houses waste so much energy".
In the supplier's second "Energy Explained" report, Mr Massara said: "If we can increase the efficiency of the UK's old and draughty housing, we can ensure that annual energy bills are some of the lowest too."
The npower chief executive warned consumers that the cost of bills was set to increase unless households introduce efficiency measures.
More top news
Those taking part in the bizarre trend say the combination of fruit juices and hot water makes for a uniquely liberating experience.
Zlatan Ibrahimovic once again proved his worth to Manchester United, with two decisive goals against Southampton at Wembley
Heavy, thundery, at times wintry showers across the UK overnight tonight and throughout Monday. Feeling increasingly cold.