Monobloc / Through-the-Wall Air Conditioners

Monobloc air conditioners — also known as through-the-wall units — house the compressor, both heat exchangers, and the fan in a single indoor cabinet, eliminating the need for a separate outdoor condensing unit entirely. Instead of refrigerant pipework running to an external unit, the system exchanges heat directly with outside air through two small wall apertures (typically 162mm, rising to 202mm on higher-capacity models), fitted with self-closing external grilles. This makes them the specification of choice wherever a conventional split system's outdoor unit isn't practical or permitted.

Where monobloc units are specified over split systems

• Flats, apartments and leasehold properties — where freeholder or management company consent for an external condenser is difficult or impossible to obtain.
• Listed buildings and conservation areas — where an external condensing unit would affect the façade or fall foul of planning restrictions; the discreet exterior grille has a far lower visual and planning impact than a wall-mounted outdoor unit.
• Refurbishments with no viable outdoor unit location — mid-terrace properties, upper-floor flats, or rooms with no adjacent external wall suitable for condenser mounting or pipe runs.
• Projects needing to avoid F-Gas-certified installation — because the unit arrives factory pre-charged with refrigerant and has no refrigerant connections made on site, installation does not require an F-Gas qualified engineer, unlike a split system.

Key specifying points

• No refrigerant connections on site. Unlike a split system, there's no pipework to run, braze, or pressure test, and no vacuum/commissioning process — installation is closer to fitting a large through-wall unit than a conventional AC install.
• Not to be confused with portable AC. Monobloc/through-the-wall units are fixed, permanently installed appliances built into the wall structure, offering split-system levels of efficiency and quiet running — not a freestanding unit with a single exhaust hose vented through a window kit.
• Genuine heat pump, not cooling-only. Current-generation units (e.g. Panasonic RAC Solo) operate as reversible air-to-air heat pumps, providing heating down to -15°C outdoor temperature as well as cooling — check the model's SCOP rating rather than assuming a cooling-only spec.
• DC Inverter control. As with split systems, output is modulated via inverter-driven compressor and fan speed rather than fixed on/off cycling, for tighter temperature control and lower running costs.
• Room sizing by capacity, not by brand assumption. Capacity ranges typically span circa 1.7kW to 3.0kW across a manufacturer's range — check the nominal cooling/heating figures against room size rather than treating all models in a range as equivalent.
• Confirm required accessories before ordering. External grille kits, insect protection kits, and side-exit or extension frameworks are frequently sold separately from the indoor unit — check the specification table for what's included versus required as an add-on.

Related collections: for properties where an outdoor condensing unit is feasible, see our Split System Air Conditioners; for supplementary or standalone cooling with no fixed installation, see our Portable Air Conditioners.