Heat pump or heat strip?
Many window units sold as “AC with heat” warm the room with an electric coil. That costs the same to run as a space heater. A true heat pump reverses its refrigerant cycle and delivers more heat than the electricity it uses. The spec sheet will say “heat pump” and list heating capacity at an outdoor temperature.
Saddle units
Gradient and Midea built saddle-style window heat pumps that straddle the sill, with the indoor and outdoor halves joined over it. New York City’s public housing authority picked both in its 2022 Clean Heat for All challenge to replace steam heat in apartments. They plug into a standard 120 V outlet and install without an electrician.
- Gradient All-Weather 120V is ENERGY STAR certified and designed for cold climates. Sold by Gradient.
- Midea’s packaged window heat pump is sold through distributors.
They cost far more than a window AC, but in a cold climate they can replace most of a room’s winter heating.
Cold-weather limits
Every heat pump loses capacity as it gets colder outside. Look at the rated heating output at the lowest temperature you see in a normal winter, not just the cooling BTU. In very cold places, keep a backup heat source for the coldest nights.
Before you buy
- Measure the window: saddle units need a minimum sill depth and clearance below the window inside and out.
- Check your lease. A window unit is usually allowed where a window AC is.
- Plug straight into the wall. Never use an extension cord.