CalMTA’s Phase II research for the Room Heat Pumps (RHPs) Market Transformation Initiative revealed that nearly half of California’s residential windows are horizontal sliders, while primary bedrooms and living rooms are the most likely locations for RHPs. This creates a challenge: the most efficient RHP designs currently fit only double-hung windows. To address this barrier, CalMTA launched a technology challenge encouraging manufacturers to develop RHPs compatible with horizontal sliders and suited for California’s climate. This report summarizes findings from a statewide homeowner survey on window types, home characteristics, and awareness of RHPs—critical insights to guide innovation and market adoption.