近年来，热泵越来越受欢迎，目前用于为1200多万美国家庭供暖（美国能源信息管理局，2017年）。虽然空气源热泵可以在高环境温度下提供出色的性能，但在供暖需求最高的低环境温度下，它们的效率（严格来说是性能系数）和容量都会降低。一些业主使用混合（或双燃料）供暖系统，在环境温度较高时使用热泵，在热泵容量不足时使用低温炉。这些混合系统允许房主避免安装更大的热泵以满足峰值供暖需求的额外资本成本。这项研究讨论了目前使用中央空调和天然气或燃油炉加热的单户家庭的供暖选择。我们确定，在大多数美国气候区，在空调使用寿命结束时，明智的做法是使用适合峰值制冷负荷的热泵，并与现有的加热炉一起运行。 我们还评估了这种转换对排放的影响，并确定了业主在投资期内盈亏平衡的电价。引用:佛罗里达州奥兰多2020年冬季会议论文

Heat pumps have grown in popularity in recent years, and are now used to heat over 12 million U.S. homes (U.S. Energy Information Administration,2017). While air source heat pumps can provide outstanding performance at high ambient temperatures, their efficiency (strictly their coefficient ofperformance) and capacity both degrade at low ambient temperatures when heating demand is highest. Some homeowners utilize hybrid (or dual fuel) heatingsystems, which use a heat pump at high ambient temperatures and a furnace at lower temperatures when the heat pump’s capacity is insufficient. Thesehybrid systems allow the homeowner to avoid the additional capital cost of installing a larger heat pump to meet peak heating demand.This study discusses heating choices for single family homes that currently use a central air unit for cooling alongside a natural gas or fuel oil furnace forheating. We determine that in most US climate zones, it is prudent to replace an air conditioner at the end of its life with a heat pump sized for the peakcooling load and operate it in tandem with the existing furnace. We also assess the emission implications of such a conversion and determine the electricityprices below which a homeowner will break even over the investment’s lifetime.