In this episode of Taking the Temperature of HVACR, host Jamie Kitchen sits down with Matthew Stoll to explore how modern heat pumps are reshaping residential, multifamily, and commercial heating. They break down what a heat pump is, how it differs from traditional air conditioning and boilers, and why today’s technology can reliably provide comfort even at -20°C, covering comfort heat pumps for space heating and domestic hot water, the importance of water temperatures, lift, and compression ratio for efficiency, and how vapor injection enables low-ambient operation. The conversation also looks at emerging microchannel heat exchangers, the shift to new A2L and natural refrigerants like propane and CO₂, and how policy, energy prices, and decarbonization goals are accelerating heat pump adoption across Europe and North America—offering a clear,