What is an air conditioner without an outdoor unit

An air conditioner without an outdoor unit (often called a fixed monobloc, not to be confused with the wheeled portable type) is a unit that integrates all the components of an air conditioner — compressor, heat exchanger, fan — into a single appliance fixed to the wall, without needing a real separate outdoor unit.

How it works

Unlike a traditional split, where the compressor lives in the outdoor unit connected by pipes to the indoor one, in an air conditioner without an outdoor unit the entire cooling cycle happens inside a single appliance. The heat extracted from the room is still vented outside, but through one or two small holes in the wall (about 5-10 cm in diameter) instead of a full outdoor unit connected by refrigerant lines.

Who it makes sense for

It’s the solution designed for anyone living in a rental, in a historic city center with architectural restrictions on facades, or in an apartment building where the bylaws don’t allow visible outdoor units. Compared to a portable unit with a hose, it offers noticeably better performance, lower noise, and a more discreet indoor footprint, staying fixed to the wall instead of having to be moved from room to room.

The trade-off compared to a traditional split

The main trade-off is efficiency: having the compressor inside the home instead of separate outside slightly reduces overall performance compared to a traditional single-split, and generally also means higher noise, since the loudest part of the system sits in the room itself. Newer models, with Inverter technology and dedicated Silent modes, have narrowed this gap considerably, but they typically remain a notch above an equivalent good single-split.

What’s still required

A common misconception is worth clearing up: wall work is still required, even if minimal. Almost all models need one or two holes in an exterior wall for the exhaust ducts to pass through — a far less invasive job than installing a full outdoor unit, but not entirely absent. We also cover this in our complete guide on how to choose an air conditioner.

Frequently asked questions

Do I still need a hole in the wall?

Yes, almost all models require one or two small holes (about 5-10 cm in diameter) to run the hot-air exhaust ducts outside. It's a far less invasive job than installing a full outdoor unit, and it's often allowed even in rentals with the landlord's consent.

Does it consume more than a traditional split air conditioner?

Generally yes, a bit more: the unit expelling heat stays inside the home alongside the one that cools, with slightly lower overall efficiency than a split where the two units are physically separate. The gap has narrowed a lot in recent years thanks to Inverter technology and integrated heat pumps in newer models.

Is it noisier than a traditional split?

Generally yes, because the compressor — the noisiest part of an air conditioner — sits inside the room rather than outside the building. Newer models have significantly reduced noise with dedicated quiet modes, though they typically remain a notch above a good traditional single-split.