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LG Libero Smart S12ET NSJ 12000 BTU Review | 46 Data compared

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  • Avg. price: ~£330
  • Cooling capacity: 3.5 kW
  • Seasonal cooling efficiency (SEER): 6.6
  • Maximum indoor-unit sound power level: 59 dB

LG Libero Smart S12ET NSJ 12000 BTU review. Compare 46 technical specifications and user reviews to see how this product ranks in the Air Conditioners category and whether it is worth buying.

7.8

Overall score

What it is: An overall evaluation of products in the Air Conditioners category, based on technical analysis and user reviews.

When it matters: When you need a quick reference for identifying the best products in the Air Conditioners category.

Score components:

80.0%

7.5

Technical Score

20.0%

9.0

User score

Very good
7.5

Technical Score

What it is: An assessment of technical performance for products in the Air Conditioners category across these key areas: Performance, Features, Design.

When it matters: When you want to compare products in the Air Conditioners category by technical performance, specifications, and available features.

Score components:

40.0%

4.9

Performance

40.0%

9.4

Features

20.0%

9.0

Design

Very good
9.0

User score

What it is: A rating that combines user reviews with the total review volume for products in the Air Conditioners category.

When it matters: When you want to know how products in the Air Conditioners category perform in everyday use and how reliable owners find them over time.

Score components:

70.0%

8.8

User reviews

30.0%

9.5

Popularity

User score:
United Kingdom
amazon
4.4
(111)

(Reviews last updated: August 2026)

Exceptional
  • 8.9
    Compactness

    Score components:

    30.0%

    7.2

    Indoor unit width

    30.0%

    10

    Indoor unit depth

    20.0%

    9.1

    Indoor unit height

    20.0%

    9.6

    Indoor unit weight

  • 8.3
    Bedroom comfort

    Score components:

    40.0%

    ?

    Night mode

    25.0%

    ?

    Timer

    20.0%

    ?

    Maximum timer duration

    15.0%

    10

    Automatic mode

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Best prices in UK

Best rankings

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Available: ranking among products currently available (including other versions of this product).
All: ranking among all products in the database.

Verdict

The LG Libero Smart is a wall-mounted split air conditioner and heat pump featuring a Dual Inverter Compressor, eco-friendly R32 refrigerant, and integrated Wi-Fi for remote operation via the LG ThinQ app. Available in multiple capacities including a common 12,000 BTU (3.5 kW) configuration, it achieves high seasonal efficiencies with a SEER of up to 6.60 (A++) for cooling and a SCOP of 4.0 (A+) for heating. Main pros include multi-mode versatility (cooling, heating, dehumidifying, and ventilating), customized energy saving via 40% to 80% Active Capacity Control, immediate thermal relief via Jet Cool/Fast Heating, a dual-protection anti-dust filter, and whisper-quiet operation down to 19 dB(A) in Silence Mode. On the downside, consumers may find that advanced features require voice assistant hardware purchased separately, professional installation is required to manage split-system line piping, and heating efficiency can naturally decline during extreme winter sub-zero temperatures.

Technical Specifications of air conditioner LG Libero Smart S12ET NSJ 12000 BTU

Technical Score

What it is: An assessment of technical performance for products in the Air Conditioners category across these key areas: Performance, Features, Design.

When it matters: When you want to compare products in the Air Conditioners category by technical performance, specifications, and available features.

Score components:

40.0%

4.9

Performance

40.0%

9.4

Features

20.0%

9.0

Design

7.5
LG Libero Smart S12ET NSJ 12000 BTU has a technical score of 7.5 points, which is higher than 52.8% of products in this category.
User score

What it is: A rating that combines user reviews with the total review volume for products in the Air Conditioners category.

When it matters: When you want to know how products in the Air Conditioners category perform in everyday use and how reliable owners find them over time.

Score components:

70.0%

8.8

User reviews

30.0%

9.5

Popularity

User score:
United Kingdom
amazon
4.4
(111)

(Reviews last updated: August 2026)

9.0
LG Libero Smart S12ET NSJ 12000 BTU has a user score of 9 points, which is higher than 86% of products in this category.
Popularity
What it is: An indicator based on the number of reviews received by products in the Air Conditioners category.
When it matters: When you prefer products in the Air Conditioners category that have been chosen and reviewed by many other buyers.
9.5
LG Libero Smart S12ET NSJ 12000 BTU has a popularity of 9.5 points, which is higher than 83.7% of products in this category.
Ratio quality/price

What it is: An indicator that combines the overall score of products in the Air Conditioners category with their prices.

When it matters: When you are comparing products in the Air Conditioners category and want a good balance between quality and price.

Score components:

60.0%

7.8

Overall score

40.0%

7.7

Price

7.8
LG Libero Smart S12ET NSJ 12000 BTU has a quality-to-price ratio of 7.8 points, which is higher than 90.5% of products in this category.
Split configuration
What it is: Split configuration states how many indoor units are paired with the air-conditioning system, such as mono, dual, triple, quad, or penta split.
When it matters: It matters when you are planning climate control for one room or several rooms from a shared outdoor unit.

Importance: LOW

mono split
Cooling capacity
What it is: Cooling capacity is the rate at which the air conditioner can remove heat from a room, expressed in kilowatts.
When it matters: Adequate capacity is essential for cooling the intended room size without excessive run time or poor temperature control.

Importance: HIGH

Good value: At least 3.5 kW

3.5 kW
LG Libero Smart S12ET NSJ 12000 BTU delivers a cooling capacity of 3.5 kW, which is higher than that of 45.9% of air conditioners and the same as that of 20% of air conditioners.
Indoor-unit capacity configuration
What it is: Indoor-unit capacity configuration shows how the system’s BTU/h capacity is distributed across its indoor units.
When it matters: It matters when sizing a multi-split system for rooms with different cooling loads.

Importance: LOW

12,000 BTU/h
Seasonal cooling efficiency (SEER)
What it is: SEER expresses the air conditioner’s average cooling efficiency over a typical season.
When it matters: A higher SEER generally means less electricity is needed to deliver the same seasonal cooling.

Importance: HIGH

Good value: At least 6.1

6.6
LG Libero Smart S12ET NSJ 12000 BTU has a SEER rating of 6.6, which is higher than that of 67.3% of air conditioners and the same as that of 3.2% of air conditioners.
Seasonal heating efficiency (SCOP)
What it is: SCOP expresses the air conditioner’s average heating efficiency over a typical season.
When it matters: A higher SCOP generally means less electricity is needed to provide the same seasonal heating.

Importance: HIGH

Good value: At least 4.0

4
LG Libero Smart S12ET NSJ 12000 BTU has a SCOP rating of 4, which is higher than that of 4.4% of air conditioners and the same as that of 49.4% of air conditioners.
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Inverter compressor
What it is: An inverter compressor can vary its operating speed instead of relying only on full-power on and off cycles.
When it matters: Variable compressor output can improve temperature stability, efficiency, and part-load noise.

Importance: HIGH

Good value: yes

yes
Does LG Libero Smart S12ET NSJ 12000 BTU use an inverter compressor? yes. 12.4% of air conditioners do, while 87.6% do not.
Heating function
What it is: A heating function reverses or supplements normal operation to warm the room.
When it matters: Heating extends seasonal usefulness and can replace a separate spot heater in mild weather.

Importance: MEDIUM

Good value: yes

yes
Can LG Libero Smart S12ET NSJ 12000 BTU heat the room? yes. 7.3% of air conditioners can, while 92.7% cannot.
Active air purification
What it is: Active air purification uses a dedicated treatment function beyond ordinary passive filtration to improve indoor air quality.
When it matters: It is useful when reducing fine particles, allergens, odors, or other airborne contaminants is a priority.

Importance: LOW

Good value: yes

no
Does LG Libero Smart S12ET NSJ 12000 BTU actively purify the air? no. 27% of air conditioners do not, while 73.1% do.
Dehumidification mode
What it is: Dehumidification mode removes moisture from room air with reduced emphasis on cooling.
When it matters: This mode improves comfort in humid weather and can help control indoor dampness.

Importance: MEDIUM

Good value: yes

yes
Does LG Libero Smart S12ET NSJ 12000 BTU include dehumidification mode? yes. 6.8% of air conditioners do, while 93.2% do not.
Fan-only mode
What it is: Fan-only mode circulates room air without running the refrigeration cycle.
When it matters: This mode provides lower-power airflow when cooling is unnecessary.

Importance: MEDIUM

Good value: yes

yes
Does LG Libero Smart S12ET NSJ 12000 BTU offer fan-only mode? yes. 6.2% of air conditioners do, while 93.8% do not.
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Color
What it is: Color identifies the main exterior finish of the indoor unit.
When it matters: Color matters when the indoor unit remains visible and should suit the room decor.

Importance: LOW

white
Body material
What it is: Body material identifies the primary exterior housing material of the indoor unit.
When it matters: Housing material affects appearance, rigidity, cleaning, and resistance to everyday wear.

Importance: LOW

plastic
Display
What it is: A display shows temperature, operating mode, timer, or status information on the indoor unit.
When it matters: A built-in display makes current settings easier to check without opening an app or using the remote.

Importance: LOW

Good value: yes

yes
LG Libero Smart S12ET NSJ 12000 BTU includes a display (yes); 18% of air conditioners do not, while 82% do.
Display position
What it is: Display position identifies where the integrated display sits on the indoor or main unit.
When it matters: A well-placed display is easier to read from the usual viewing angle without obstructing the room layout.

Importance: LOW

front right
Physical control methods
What it is: Physical control methods identify the supplied remote and user-facing controls on the unit.
When it matters: Physical controls matter when you want to operate the air conditioner without relying on Wi-Fi, an app, or voice control.

Importance: MEDIUM

Good value: remote control and onboard controls

remote control
LG Libero Smart S12ET NSJ 12000 BTU provides remote control physical controls, ahead of 1.1% of air conditioners and equal to 81.5%.
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LG Libero Smart S12ET NSJ 12000 BTU vs the average air conditioner

  • 2 more fan speeds
    LG Libero Smart S12ET NSJ 12000 BTU provides more fan speed options than the average air conditioner (5 vs 3).
    What it is: The number of selectable fan speeds determines how finely airflow and noise can be adjusted.
    When it matters: More speed settings make it easier to balance cooling intensity, sound, and comfort.

    Importance: MEDIUM

    Good value: At least 3 speeds

    LG Libero Smart S12ET NSJ 12000 BTU provides more fan speed options than the average air conditioner (5 vs 3).5 vs 3
  • 1.6 cm shallower indoor unit
    LG Libero Smart S12ET NSJ 12000 BTU has a shallower indoor unit than the average air conditioner (18.9 cm vs 20.5 cm).
    What it is: Indoor unit depth is the front-to-back distance of the wall-mounted unit.
    When it matters: A shallower indoor unit protrudes less into the room and looks less bulky on the wall.

    Importance: MEDIUM

    Good value: Up to 22 cm

    LG Libero Smart S12ET NSJ 12000 BTU has a shallower indoor unit than the average air conditioner (18.9 cm vs 20.5 cm).18.9 cm vs 20.5 cm
  • 155 m³/h higher indoor-unit airflow
    LG Libero Smart S12ET NSJ 12000 BTU delivers a higher indoor airflow rate than the average air conditioner (750 m³/h vs 595 m³/h).
    What it is: Maximum indoor-unit airflow is the greatest volume of air the indoor unit can circulate in one hour.
    When it matters: Higher airflow can distribute cooled or heated air more quickly, especially in larger rooms.

    Importance: HIGH

    Good value: At least 600 m³/h

    LG Libero Smart S12ET NSJ 12000 BTU delivers a higher indoor airflow rate than the average air conditioner (750 m³/h vs 595 m³/h).750 m³/h vs 595 m³/h
  • 0.3 points higher seasonal cooling efficiency
    LG Libero Smart S12ET NSJ 12000 BTU achieves a higher seasonal cooling efficiency (SEER) than the average air conditioner (6.6 vs 6.3).
    What it is: SEER expresses the air conditioner’s average cooling efficiency over a typical season.
    When it matters: A higher SEER generally means less electricity is needed to deliver the same seasonal cooling.

    Importance: HIGH

    Good value: At least 6.1

    LG Libero Smart S12ET NSJ 12000 BTU achieves a higher seasonal cooling efficiency (SEER) than the average air conditioner (6.6 vs 6.3).6.6 vs 6.3
  • 9.48x more popular
    LG Libero Smart S12ET NSJ 12000 BTU is more popular than the average air conditioner (9.48 vs 1).
    What it is: An indicator based on the number of reviews received by products in the Air Conditioners category.
    When it matters: When you prefer products in the Air Conditioners category that have been chosen and reviewed by many other buyers.
    LG Libero Smart S12ET NSJ 12000 BTU is more popular than the average air conditioner (9.48 vs 1).9.48 vs 1
  • 12.5% higher user score
    LG Libero Smart S12ET NSJ 12000 BTU has a higher user score than the average air conditioner (9 vs 8).
    What it is: A rating that combines user reviews with the total review volume for products in the Air Conditioners category.
    When it matters: When you want to know how products in the Air Conditioners category perform in everyday use and how reliable owners find them over time.
    LG Libero Smart S12ET NSJ 12000 BTU has a higher user score than the average air conditioner (9 vs 8).9 vs 8
  • 10.5% better value for money
    LG Libero Smart S12ET NSJ 12000 BTU offers better value for money than the average air conditioner (7.77 vs 7.036).
    What it is: An indicator that combines the overall score of products in the Air Conditioners category with their prices.
    When it matters: When you are comparing products in the Air Conditioners category and want a good balance between quality and price.
    LG Libero Smart S12ET NSJ 12000 BTU offers better value for money than the average air conditioner (7.77 vs 7.036).7.77 vs 7.04
  • 51.5% cheaper
    LG Libero Smart S12ET NSJ 12000 BTU is cheaper than the average air conditioner (£330 vs £500).
    LG Libero Smart S12ET NSJ 12000 BTU is cheaper than the average air conditioner (£330 vs £500).£330 vs £500
  • 155 m³/h higher indoor-unit airflow
    LG Libero Smart S12ET NSJ 12000 BTU delivers a higher indoor airflow rate than the average air conditioner (750 m³/h vs 595 m³/h).
  • 0.3 points higher seasonal cooling efficiency
    LG Libero Smart S12ET NSJ 12000 BTU achieves a higher seasonal cooling efficiency (SEER) than the average air conditioner (6.6 vs 6.3).
  • 2 more fan speeds
    LG Libero Smart S12ET NSJ 12000 BTU provides more fan speed options than the average air conditioner (5 vs 3).
  • 1.6 cm shallower indoor unit
    LG Libero Smart S12ET NSJ 12000 BTU has a shallower indoor unit than the average air conditioner (18.9 cm vs 20.5 cm).

Total
Overall
Performance
Features
Design
  • 3 dB higher outdoor sound power
    LG Libero Smart S12ET NSJ 12000 BTU operates with a louder outdoor unit than the average air conditioner (65 dB vs 62 dB).
  • 3 dB higher indoor sound power
    LG Libero Smart S12ET NSJ 12000 BTU operates with a louder indoor unit than the average air conditioner (59 dB vs 56 dB).
  • Does not support an anti-mould function
    LG Libero Smart S12ET NSJ 12000 BTU does not support an anti-mould function, while the average air conditioner supports an anti-mould function.
  • 1.8 cm taller indoor unit
    LG Libero Smart S12ET NSJ 12000 BTU has a taller indoor-unit height than the average air conditioner (30.8 cm vs 29 cm).
  • 3.2 cm wider indoor unit
    LG Libero Smart S12ET NSJ 12000 BTU has a wider indoor unit than the average air conditioner (83.7 cm vs 80.5 cm).
  • 3 dB higher outdoor sound power
    LG Libero Smart S12ET NSJ 12000 BTU operates with a louder outdoor unit than the average air conditioner (65 dB vs 62 dB).
    What it is: Maximum outdoor-unit sound power level measures the greatest acoustic power emitted by the outdoor unit.
    When it matters: A lower value reduces the likelihood of disturbing neighbours or nearby outdoor spaces.

    Importance: MEDIUM

    Good value: Up to 65 dB

    LG Libero Smart S12ET NSJ 12000 BTU operates with a louder outdoor unit than the average air conditioner (65 dB vs 62 dB).65 dB vs 62 dB
  • Does not support an anti-mould function
    LG Libero Smart S12ET NSJ 12000 BTU does not support an anti-mould function, while the average air conditioner supports an anti-mould function.
    What it is: Indicates whether the air conditioner has an anti-mould function that helps keep internal components dry.
    When it matters: When you want to reduce moisture buildup, stale odors, and mould growth inside the unit.

    Importance: LOW

    Good value: yes

    LG Libero Smart S12ET NSJ 12000 BTU does not support an anti-mould function, while the average air conditioner supports an anti-mould function.
  • 3 dB higher indoor sound power
    LG Libero Smart S12ET NSJ 12000 BTU operates with a louder indoor unit than the average air conditioner (59 dB vs 56 dB).
    What it is: Maximum indoor-unit sound power level measures the greatest acoustic power emitted by the indoor unit.
    When it matters: A lower value supports a quieter room, which is especially useful in bedrooms and workspaces.

    Importance: HIGH

    Good value: Up to 55 dB

    LG Libero Smart S12ET NSJ 12000 BTU operates with a louder indoor unit than the average air conditioner (59 dB vs 56 dB).59 dB vs 56 dB
  • 1.8 cm taller indoor unit
    LG Libero Smart S12ET NSJ 12000 BTU has a taller indoor-unit height than the average air conditioner (30.8 cm vs 29 cm).
    What it is: Indoor unit height is the vertical dimension of the wall-mounted indoor unit.
    When it matters: A shorter indoor unit needs less vertical wall space and fits above doors or windows more easily.

    Importance: MEDIUM

    Good value: Up to 30 cm

    LG Libero Smart S12ET NSJ 12000 BTU has a taller indoor-unit height than the average air conditioner (30.8 cm vs 29 cm).30.8 cm vs 29 cm
  • 3.2 cm wider indoor unit
    LG Libero Smart S12ET NSJ 12000 BTU has a wider indoor unit than the average air conditioner (83.7 cm vs 80.5 cm).
    What it is: Indoor unit width is the horizontal side-to-side dimension of the wall-mounted unit.
    When it matters: A narrower indoor unit fits more easily on limited wall sections and between furniture or openings.

    Importance: MEDIUM

    Good value: Up to 80 cm

    LG Libero Smart S12ET NSJ 12000 BTU has a wider indoor unit than the average air conditioner (83.7 cm vs 80.5 cm).83.7 cm vs 80.5 cm
Total
Performance
Features
Design

Graphic comparison of LG Libero Smart S12ET NSJ 12000 BTU and other products in the Air Conditioners category

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Third-party reviews

United Kingdom
amazon
4.4
111 Reviews

(Reviews last updated: August 2026)

What customers like about LG Libero Smart S12ET NSJ 12000 BTU?

  • Ultra-quiet operation with minimal noise and vibrations from both indoor and outdoor units
  • Highly energy-efficient climate control with A++/A+ energy rating and Active Energy Control
  • Fast and effective cooling and heating performance powered by Dual Inverter technology
  • Seamless Wi-Fi connectivity and instant remote control via the LG ThinQ smartphone app
  • Straightforward and quick installation process
  • Sleek, compact, and modern indoor unit design

What customers dislike about LG Libero Smart S12ET NSJ 12000 BTU?

  • Occasional app connectivity issues or sync drops following software updates
  • Required installation piping and specific connection accessories are sometimes missing from standard retail packages
  • Active Energy Control mode is restricted and does not function while operating in heating mode

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