LG Multi F MU3R19.U21 3-Port Multi-Split Outdoor Unit 5.3kW
Available to order — dispatched on the lead time shown below.
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Retail prices include VAT.
The LG Multi F MU3R19.U21 triple-port outdoor condenser offers versatile multi-room heating and air conditioning from a single, space-saving exterior enclosure. Capable of powering up to three independently regulated indoor fan coils, it is an exceptional solution for UK semi-detached and detached homes seeking whole-floor comfort without cluttering garden areas with several condensers. Powered by LG's R32 smart inverter twin rotary technology, this unit reduces electricity draw significantly compared to older systems, while reaching an outstanding A+++ energy efficiency standard. Its robust casing features protective anti-corrosion condenser fin coatings specifically conceived to battle high-humidity UK climates. Indoors, occupants can select from high-wall Artcool or Standard Plus units, ceiling cassettes, or slim ducted units to fit room decor. Supporting integrated smart home control through LG ThinQ, the MU3R19.U21 allows mobile scheduling and active voice control via Alexa and Google Home. Professional F-Gas commissioning is strictly required.
Need it installed?
We'll match you with a local HVAC engineer.
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
Technical documents & videos
More from LG →Official LG manual
The manufacturer's PDF for this model is being sourced and will be downloadable here.
Full Specifications
Physical dimensions
Exact dimensions for this model are being confirmed with LG — ask us and we will send the cut sheet with mounting and clearance figures.
Description
The LG Multi F MU3R19.U21 triple-port outdoor condenser offers versatile multi-room heating and air conditioning from a single, space-saving exterior enclosure. Capable of powering up to three independently regulated indoor fan coils, it is an exceptional solution for UK semi-detached and detached homes seeking whole-floor comfort without cluttering garden areas with several condensers. Powered by LG's R32 smart inverter twin rotary technology, this unit reduces electricity draw significantly compared to older systems, while reaching an outstanding A+++ energy efficiency standard. Its robust casing features protective anti-corrosion condenser fin coatings specifically conceived to battle high-humidity UK climates. Indoors, occupants can select from high-wall Artcool or Standard Plus units, ceiling cassettes, or slim ducted units to fit room decor. Supporting integrated smart home control through LG ThinQ, the MU3R19.U21 allows mobile scheduling and active voice control via Alexa and Google Home. Professional F-Gas commissioning is strictly required.
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Side-by-side specs for other multi-split system ac in a similar BTU range.
Common questions about the LG Multi F MU3R19.U21 3-Port Multi-Split Outdoor Unit 5.3kW
How many BTU is the LG Multi F MU3R19.U21 3-Port Multi-Split Outdoor Unit 5.3kW?
The LG Multi F MU3R19.U21 3-Port Multi-Split Outdoor Unit 5.3kW has a cooling capacity of 18,000 BTU, suitable for 3 rooms (up to 50m² combined).
What room size is the LG Multi F MU3R19.U21 3-Port Multi-Split Outdoor Unit 5.3kW suitable for?
The LG Multi F MU3R19.U21 3-Port Multi-Split Outdoor Unit 5.3kW is recommended for rooms 3 rooms (up to 50m² combined).
Can I install the LG Multi F MU3R19.U21 3-Port Multi-Split Outdoor Unit 5.3kW myself?
No — this unit requires professional installation by a qualified F-gas engineer. Use our Find an Installer service to get matched with a local HVAC professional.
Is the LG Multi F MU3R19.U21 3-Port Multi-Split Outdoor Unit 5.3kW smart-home compatible?
Yes — the LG Multi F MU3R19.U21 3-Port Multi-Split Outdoor Unit 5.3kW supports LG ThinQ, Amazon Alexa, Google Assistant for app and voice control.
How long does delivery of the LG Multi F MU3R19.U21 3-Port Multi-Split Outdoor Unit 5.3kW take?
This unit is 2-4 working days. Delivery is then 1–2 working days to most UK mainland addresses, and 3–6 working days into the EU.
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Mitsubishi ElectricAnnual energy savings estimate
How much this A+++-rated unit could save versus a standard C-rated model, based on your usage.
This unit
136 kWh/yr
EER 14
Standard model
237 kWh/yr
EER 8
Est. saving
£27.47
102 kWh/yr less
Estimate based on the unit's energy-rating efficiency factor and cooling capacity (18,000 BTU). Actual savings vary with room size, climate and usage patterns.
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
£1276
This AC / season
£425
You save / season
£851
~67% less electricity
| Heating method | Electricity / season | Cost / season | Efficiency | Summer cooling |
|---|---|---|---|---|
| This heat-pump AC | 1575 kWh | £425 | Up to 300% | |
| Plug-in electric heater | 4726 kWh | £1276 | 100% | |
| Electric storage heater | 4726 kWh | £1276 | 100% |
Heat output estimated from this unit's 21,500 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 →
Share your savings
This heat-pump AC costs only £425/season to heat a room vs £1276 for an electric heater - that's £851 saved. https://stockool.store/products/lg-multi-f-mu3r19-u21-3-port-multi-split-outdoor-unit
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