The Northwest Energy Efficiency Alliance (NEEA) hired ILLUME Advising to pursue two concurrent studies around water heater installers. The first was intended to focus on observational research of cold climate heat pump water heater (HPWH) installations in the Northwest to better understand the depth of previously established installation challenges, specifically in cold climate scenarios. The second study (also qualitative) was geared to better understand any challenges installers and plumbers in the region might face around recommending and installing HPWHs in existing single-family homes, and their hesitation to do so.