As the city and state try to electrify buildings to lower GHG emissions, packaged terminal heat pumps (PTHPs) offer a cost-effective, low-carbon way to provide heating and cooling in new construction or in retrofitted multifamily buildings. Historically, PTHPs have been inefficient in cold climates, swapping over to electric resistance heating or central heating at temperatures below 40℉. But new cold climate PTHPs should be capable of heating at ambient temperatures down to -5℉, while maintaining relatively high coefficients of performance. Our team has conducted multiple studies now on cold-climate PTHPs that have been installed in new construction projects in NYC. Our findings offer a more nuanced view and offer suggestions for greater performance and ultimately tenant comfort. In this presentation we hope to provide some background on PTHP units and discuss findings from two research projects. We would also provide an overview of our experimental method and the lessons learned during data collection to help inform future research.