Heat Pumps
Most heat pump questions fall into three buckets: whether to buy one, why it's not performing as expected, and how to keep it running efficiently. The efficiency numbers matter — a COP of 3.5 means 3.5 units of heat for every unit of electricity, which is why heat pumps beat electric resistance heat in most climates. Cold-weather performance is the sticking point: below 35°F, standard units lose efficiency fast, which is why manufacturers now make cold-climate models rated to −13°F. A heat pump that falls back on strip heat all winter isn't saving money. The guides here cover the full picture — sizing, SEER2/HSPF2 ratings, comparison against furnaces and boilers, troubleshooting ice buildup and short cycling, and the buying checklist that keeps you from over- or under-sizing.