There are different kinds of heat pump technologies, but for simplicity’s sake, we’ll focus on the appliances making the most waves right now.Thanks to some relatively recent breakthroughs in heat pump technologies, this works even in cold climates because the refrigerant will absorb heat as long as it’s colder than its surroundings.The first electric ground-source heat pump is credited to American inventor Robert C. Webber, who was tinkering with a deep freezer in his cellar in the late 1940s when he realized it produced scalding water.That energy crisis is really stark in Europe, where the cost of gas has risen from around $5 per million British thermal units (MMBtu) to $55 per MMBtu over the past couple of years alone.Some cities — like Berkeley, California — have even banned new gas hookups in homes and buildings."