LG MU3R19.U21 5.3kW Multi-Split Outdoor Unit
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The LG MU3R19.U21 is a versatile 5.3kW multi-split outdoor unit capable of supporting up to three indoor units. This system is perfect for medium-sized homes where independent temperature control is required across multiple living areas or bedrooms. Featuring LG’s signature dual inverter technology, the unit ensures rapid cooling and heating while significantly reducing energy consumption. Its intelligent load-balancing capability ensures that each connected indoor unit receives the precise amount of refrigerant needed, maintaining optimal comfort levels throughout the day. The unit is designed for durability and quiet performance, making it suitable for residential installations where noise reduction is a priority. With its sleek, weather-resistant casing, it integrates seamlessly into any UK property exterior. This system is a smart investment for homeowners seeking a flexible, efficient, and long-lasting climate control solution that can be expanded or adjusted to meet changing household needs.
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Smart-home ready
Connects natively with the systems below — control by app or voice.
- Free UK mainland delivery on in-stock units
- Manufacturer warranty included
- 14-day returns
Watch & install
Official LG product and installation video — see exactly how this unit is set up and fitted.
Manufacturer instructions
The LG MU3R19.U21 is a professional-grade multi-split outdoor unit that must be installed by a qualified HVAC technician in compliance with local F-gas regulations. The unit requires a stable, level mounting surface with adequate clearance for airflow. Installation involves connecting refrigerant piping between the outdoor unit and up to three indoor units, followed by a mandatory pressure test and vacuum evacuation to remove moisture from the lines. Electrical connections must be made according to the provided wiring diagrams, ensuring proper grounding and circuit protection. Once installed, the system requires a leak check before opening the service valves to release the refrigerant charge. First power-on should only occur after all connections are verified. Refer to the official LG installation manual for specific torque settings, pipe sizing, and electrical requirements.
Fixed units must be installed by a qualified F-gas engineer. Find an installer — we'll match you with a local HVAC professional.
Installation & Owner's Manual
Official LG PDF — download or print before your unit arrives.
Full Specifications
Description
The LG MU3R19.U21 is a versatile 5.3kW multi-split outdoor unit capable of supporting up to three indoor units. This system is perfect for medium-sized homes where independent temperature control is required across multiple living areas or bedrooms. Featuring LG’s signature dual inverter technology, the unit ensures rapid cooling and heating while significantly reducing energy consumption. Its intelligent load-balancing capability ensures that each connected indoor unit receives the precise amount of refrigerant needed, maintaining optimal comfort levels throughout the day. The unit is designed for durability and quiet performance, making it suitable for residential installations where noise reduction is a priority. With its sleek, weather-resistant casing, it integrates seamlessly into any UK property exterior. This system is a smart investment for homeowners seeking a flexible, efficient, and long-lasting climate control solution that can be expanded or adjusted to meet changing household needs.
Compare similar units
Side-by-side specs for other multi-split system ac in a similar BTU range.
Winter heating cost: this AC vs electric heaters
This unit reverses to heat your room in winter. Based on its 6 kW heat output used 5 hrs/day over a 150-day UK heating season at £0.27/kWh.
Electric heater / season
£1187
This AC / season
£396
You save / season
£791
~67% less electricity
| Heating method | Electricity / season | Cost / season | Efficiency | Summer cooling |
|---|---|---|---|---|
| This heat-pump AC | 1465 kWh | £396 | Up to 300% | |
| Plug-in electric heater | 4396 kWh | £1187 | 100% | |
| Electric storage heater | 4396 kWh | £1187 | 100% |
Heat output estimated from this unit's 20,000 BTU/hr rating. A heat pump moves heat (COP ≈ 3), so it uses about a third of the electricity of a direct-electric heater for the same warmth. Actual savings vary with room size, insulation, tariff and usage. See the full comparison →
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