A New Hampshire homeowner shopping for a replacement for an aging furnace sparked a lively debate online after comparing two very different cold-climate heat pump quotes: a $24,000 Mitsubishi Hyper-Heat system and a $17,000 Arctic Heat Pump. With winter temperatures potentially dropping to minus 25 degrees Fahrenheit, the question was simple but high stakes: Which unit will actually hold up when the cold gets serious? In a Reddit post on r/heatp…