Living in a flat where the building rules ban external units, or in a listed building where any facade change requires approval? There is a solution: a monosplit without an outdoor unit. It works without the usual external box and still gets installed fixed to the wall. Here is how it works and whether it makes sense for your situation.
A standard air conditioner has two parts: an indoor split and an outdoor unit on the facade. Models without an outdoor unit handle the thermal exchange differently. Instead of an external box, two small holes (roughly 15 to 20 cm in diameter) are drilled through the perimeter wall. The concept is similar to a portable AC unit, but the device is wall-fixed and considerably more efficient. If you're still working out which type of air conditioner suits your home, our air conditioner buying guide is a good place to start.
What Is an Air Conditioner Without an Outdoor Unit?
It's a unit made up entirely of the indoor split. Heat is expelled not through a separate external box, but through two openings drilled into the outer wall of the building. The entire system, motor, compressor and heat exchanger, sits inside the indoor unit. That's why the indoor unit is somewhat bulkier and heavier than a standard indoor split.
When Does It Make Sense to Install One?
This type of unit is the right call when:
- building regulations or a homeowners' association prohibit any visible external unit on the facade
- urban planning or architectural restrictions prevent any modification to the building's exterior
- the building is listed and any exterior work requires special authorisation
Pros and Cons
Pros
- Installable where conventional air conditioners are not permitted. This is the main reason to choose this type of unit.
- No visual impact on the building facade. The exterior stays untouched, which avoids disputes with building management or local planning authorities.
- Simpler maintenance. There's only one unit to service, with no external box exposed to the elements.
- No outdoor noise. The unit makes no sound on the building facade, which matters in dense urban areas.
Cons
- Higher purchase price compared to equivalent standard models with an external unit.
- Larger indoor unit. Because the motor and compressor are built into the indoor split, the unit is bulkier than a conventional indoor split.
- Can only be installed on an exterior wall. The two ducts have to pass through to the outside, so interior walls are not an option.
- Higher indoor noise level compared to a standard split with a separate external unit.
Browse all available models in our air conditioners without outdoor unit category. For maintenance, see our guide on cleaning your air conditioner. If you're looking for a mobile alternative, check our range of portable air conditioners.