Dunn, who took up his new post earlier this week, will look after a range of campaigns aimed at focusing on misleading doorstep selling, consumer complaints and debt.
Describing the energy industry as a fiercely competitive market, Dunn said it was vital that consumers are made aware of the choices available and the potential avenues for complaint.
He will head a 13-strong team answering to Energywatch chairman Ann Robinson.
Head of public affairs at computer firm Logica between 2000 and 2003, Dunn was previously head of PR at high-street electrical retailer Dixons between 1998 and 2000. During his 11 years in the PR industry he was also an associate director at Hill & Knowlton and worked for the Communications Workers Union (CWU) on the successful campaign to defeat plans by the last Conservative government to privatise the Post Office (eventually privatised under Labour).
Last year, Energywatch delivered a furious rebuke to regulator Ofgem, when it lifted gas and electricity price controls, saying the poorest consumers would lose out.
The organisation's previous head of comms Adam Scorer has left the watchdog to become a house husband.