This DIY heat pump plugs into a wall outlet and has no outdoor unit

A company called MRCOOL has launched a heat pump for a single room that skips the outdoor unit entirely. Called the Monoblock MTHP, it packs the whole refrigeration system into one wall-mounted box, so there's no separate condenser sitting outside and no refrigerant lines to run between indoors and out. It plugs into a regular 115-volt household outlet, which means you likely won't need to add a new 240V circuit or upgrade your electrical panel.

It's meant for smaller spaces like a garage, home office, sunroom, accessory dwelling unit, or tiny home, not a whole house. It puts out 10,000 Btu/hour of cooling and 9,000 Btu/hour of heating, works down to 5 degrees Fahrenheit outside, and also dehumidifies and runs as a fan. Efficiency is rated at 15 SEER2 (cooling) and 7.5 HSPF2 (heating), decent for a compact unit but below what a typical mini-split delivers.

Installation still isn't as simple as setting it on the floor and plugging it in. You need an exterior wall, since the unit requires two holes cut through it for outside air intake and exhaust, plus a smaller one for condensate drainage. At about 93 pounds, it's likely a two-person job, and any wiring or wall-cutting still has to follow local building codes. Because the refrigerant circuit comes sealed from the factory, though, you won't need an HVAC technician to charge it. Preorders are open through various retailers, with prices ranging from about $1,370 to $1,550 and one retailer listing an August 31 release date.