What is the best window air conditioner with heat?

Usually not. Many window and through-the-wall units sold "with heat" warm the room with an electric coil, as a space heater does: each watt of electricity becomes about one watt of heat (3,412 BTU per kilowatt-hour). A heat pump instead moves heat in from outdoors and, at its rating point, delivers about two and a half to three and a half times as much heat per watt, though its output falls as it gets colder outside and some models switch to a back-up coil in freezing weather. You can check a listing yourself: divide its rated heating output in BTU by its heating wattage, then by 3.412. A result near 1 is a coil; a result well above it, about 2 to 3.5 at the rating point, is a heat pump. compare.ac names a coil or a heat pump only from a unit's own evidence (those figures, the retailer's heater type and the listing's title), never when they disagree, and calls a unit a heat pump only when its heater type or title says so too, because some listings copy the cooling wattage into the heating figure.

Multiply its heating wattage by your electricity price. At the US average residential price of 18.44¢ per kWh (EIA, May 2026), every 1,000 watts costs about 18¢ an hour at full heat. A 3,450-watt coil, common on 230-volt units whose listings rate it at about 10,600 to 11,000 BTU of heat, costs about 64¢ an hour; a 115-volt unit's coil of about 1,200 watts costs about 22¢ but delivers only around 3,500 to 4,200 BTU. A heat pump delivering the same heat draws a fraction of the power. The thermostat cycles the heat on and off, so a real hour usually costs less than the full-heat figure.

For more than a little coil heat, yes. The electrical code limits a plug-in room air conditioner to 80% of its circuit's rating, or 50% when the circuit also feeds lights or other outlets. On a standard 15-amp, 120-volt circuit (NEMA 5-15 outlet) that 80% is 1,440 watts, only about 4,900 BTU of coil heat, which is why 115-volt units with coil heat deliver roughly 3,500 to 4,200 BTU. Coil heat of 10,000 BTU or more needs a 208/230-volt circuit with a matching outlet (NEMA 6-15, 6-20 or 6-30, set by the unit's current draw). A heat pump moves several times more heat per watt, so a 115-volt heat pump can deliver well beyond that on a standard outlet. Match the plug on the listing to the outlet in your wall: compare.ac shows each unit's voltage and plug where its retailer states them for that exact model.