There has been an uptick of interest in renewable energy heating and cooling in the past year, with several U.S. states and other countries establishing favorable incentives. After a two-year slump due to the global economic downturn, Navigant Research predicts that the geothermal heat pump market (GHP) will nearly triple to $17.2 billion by 2020, which is a “slow but steady growth” for the industry, according to Navigant analyst Mackinnon Lawrence.