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LG S12ER Review | 46 Data compared

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  • Avg. price: ~£360
  • Cooling capacity: 2.5 kW
  • Seasonal cooling efficiency (SEER): 6.5
  • Maximum indoor-unit sound power level: 59 dB

LG S12ER 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.

7.2

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%

6.9

Technical Score

20.0%

8.2

User score

Very good
6.9

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%

4.0

Performance

40.0%

8.7

Features

20.0%

9.1

Design

Good
8.2

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%

8.4

User reviews

30.0%

7.9

Popularity

User score:
United Kingdom
amazon
4.2
(45)

(Reviews last updated: August 2026)

Excellent
  • 8.3
    Compactness

    Score components:

    30.0%

    5.3

    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

  • lg-s12er
  • lg-s12er
lg-s12er
lg-s12er

Best prices in UK

Best rankings

?

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

Verdict

The LG S12ER is a wall-mounted split-system air conditioner and heat pump featuring a 3.5 kW cooling capacity (12,000 BTU) and a 4.0 kW heating capacity, utilizing eco-friendly R32 refrigerant. Powered by an energy-efficient Dual Inverter Compressor, it achieves an impressive A++ energy rating for cooling and an A+ rating for heating, while operating at a whisper-quiet sleep mode noise level as low as 19 dB(A). Key advantages include its Active Energy Control for multi-level power optimization, Jet Cool technology for rapid temperature drops, auto-cleaning functionality to prevent mold, and integrated Wi-Fi connectivity for smart control via the ThinQ app. However, a notable disadvantage is that its performance and maximum airflow can drop slightly during extreme low-ambient outdoor temperatures, and the unit requires professional, multi-person installation due to the heavy split-system configuration.

Technical Specifications of air conditioner LG S12ER

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%

4.0

Performance

40.0%

8.7

Features

20.0%

9.1

Design

6.9
LG S12ER has a technical score of 6.88 points, which is lower than 82% 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%

8.4

User reviews

30.0%

7.9

Popularity

User score:
United Kingdom
amazon
4.2
(45)

(Reviews last updated: August 2026)

8.2
LG S12ER has a user score of 8.24 points, which is higher than 78.1% 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.
7.9
LG S12ER has a popularity of 7.9 points, which is higher than 76.4% 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%

7.2

Overall score

40.0%

7.4

Price

7.2
LG S12ER has a quality-to-price ratio of 7.2 points, which is higher than 60.1% 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

2.5 kW
LG S12ER delivers a cooling capacity of 2.5 kW, which is lower than that of 88.8% of air conditioners and the same as that of 10% 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

6.5
LG S12ER has a SEER rating of 6.5, which is higher than that of 62.2% of air conditioners and the same as that of 4.5% 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 S12ER 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.
Show more
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 S12ER 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 S12ER 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 S12ER 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 S12ER 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 S12ER offer fan-only mode? yes. 6.2% of air conditioners do, while 93.8% do not.
Show more
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 S12ER 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 and onboard controls
LG S12ER provides remote control and onboard controls physical controls, ahead of 83.2% of air conditioners and equal to 16.9%.
Show more

LG S12ER vs the average air conditioner

  • 3 more fan speeds
    LG S12ER provides more fan speed options than the average air conditioner (6 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 S12ER provides more fan speed options than the average air conditioner (6 vs 3).6 vs 3
  • Broader physical control options
    For physical control setup, LG S12ER lists remote control and onboard controls, while the average air conditioner lists remote control.
    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

    For physical control setup, LG S12ER lists remote control and onboard controls, while the average air conditioner lists remote control.remote control and onboard controls vs remote control
  • 1.6 cm shallower indoor unit
    LG S12ER 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 S12ER has a shallower indoor unit than the average air conditioner (18.9 cm vs 20.5 cm).18.9 cm vs 20.5 cm
  • 95 m³/h higher indoor-unit airflow
    LG S12ER delivers a higher indoor airflow rate than the average air conditioner (690 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 S12ER delivers a higher indoor airflow rate than the average air conditioner (690 m³/h vs 595 m³/h).690 m³/h vs 595 m³/h
  • 0.2 points higher seasonal cooling efficiency
    LG S12ER achieves a higher seasonal cooling efficiency (SEER) than the average air conditioner (6.5 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 S12ER achieves a higher seasonal cooling efficiency (SEER) than the average air conditioner (6.5 vs 6.3).6.5 vs 6.3
  • 7.88x more popular
    LG S12ER is more popular than the average air conditioner (7.88 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 S12ER is more popular than the average air conditioner (7.88 vs 1).7.88 vs 1
  • 3% higher user score
    LG S12ER has a higher user score than the average air conditioner (8.24 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 S12ER has a higher user score than the average air conditioner (8.24 vs 8).8.24 vs 8
  • 38.9% cheaper
    LG S12ER is cheaper than the average air conditioner (£360 vs £500).
    LG S12ER is cheaper than the average air conditioner (£360 vs £500).£360 vs £500
  • 95 m³/h higher indoor-unit airflow
    LG S12ER delivers a higher indoor airflow rate than the average air conditioner (690 m³/h vs 595 m³/h).
  • 0.2 points higher seasonal cooling efficiency
    LG S12ER achieves a higher seasonal cooling efficiency (SEER) than the average air conditioner (6.5 vs 6.3).
  • 3 more fan speeds
    LG S12ER provides more fan speed options than the average air conditioner (6 vs 3).
  • Broader physical control options
    For physical control setup, LG S12ER lists remote control and onboard controls, while the average air conditioner lists remote control.
  • 1.6 cm shallower indoor unit
    LG S12ER has a shallower indoor unit than the average air conditioner (18.9 cm vs 20.5 cm).

Total
Overall
Performance
Features
Design
  • 1 kW lower cooling capacity
    LG S12ER delivers a lower cooling capacity than the average air conditioner (2.5 kW vs 3.5 kW).
  • 3 dB higher outdoor sound power
    LG S12ER operates with a louder outdoor unit than the average air conditioner (65 dB vs 62 dB).
  • 3 dB higher indoor sound power
    LG S12ER operates with a louder indoor unit than the average air conditioner (59 dB vs 56 dB).
  • Does not support automatic self-cleaning
    LG S12ER does not support automatic self-cleaning, while the average air conditioner supports automatic self-cleaning.
  • 17 hours shorter timer duration
    LG S12ER allows a shorter timer setting than the average air conditioner (7 hours vs 24 hours).
  • 1.8 cm taller indoor unit
    LG S12ER has a taller indoor-unit height than the average air conditioner (30.8 cm vs 29 cm).
  • 8.2 cm wider indoor unit
    LG S12ER has a wider indoor unit than the average air conditioner (88.7 cm vs 80.5 cm).
  • 1 kW lower cooling capacity
    LG S12ER delivers a lower cooling capacity than the average air conditioner (2.5 kW vs 3.5 kW).
    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

    LG S12ER delivers a lower cooling capacity than the average air conditioner (2.5 kW vs 3.5 kW).2.5 kW vs 3.5 kW
  • Does not support automatic self-cleaning
    LG S12ER does not support automatic self-cleaning, while the average air conditioner supports automatic self-cleaning.
    What it is: Indicates whether the air conditioner can run an automatic internal cleaning or drying cycle.
    When it matters: When you want easier maintenance and less residual moisture or dirt inside the heat exchanger.

    Importance: MEDIUM

    Good value: yes

    LG S12ER does not support automatic self-cleaning, while the average air conditioner supports automatic self-cleaning.
  • 17 hours shorter timer duration
    LG S12ER allows a shorter timer setting than the average air conditioner (7 hours vs 24 hours).
    What it is: Maximum timer duration is the longest interval that can be scheduled before automatic operation changes.
    When it matters: A longer timer window offers more flexibility for overnight use and advance scheduling.

    Importance: HIGH

    Good value: At least 24 hours

    LG S12ER allows a shorter timer setting than the average air conditioner (7 hours vs 24 hours).7 hours vs 24 hours
  • 3 dB higher outdoor sound power
    LG S12ER 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 S12ER operates with a louder outdoor unit than the average air conditioner (65 dB vs 62 dB).65 dB vs 62 dB
  • 3 dB higher indoor sound power
    LG S12ER 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 S12ER 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 S12ER 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 S12ER has a taller indoor-unit height than the average air conditioner (30.8 cm vs 29 cm).30.8 cm vs 29 cm
  • 8.2 cm wider indoor unit
    LG S12ER has a wider indoor unit than the average air conditioner (88.7 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 S12ER has a wider indoor unit than the average air conditioner (88.7 cm vs 80.5 cm).88.7 cm vs 80.5 cm
Total
Performance
Features
Design

Graphic comparison of LG S12ER and other products in the Air Conditioners category

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Third-party reviews

United Kingdom
amazon
4.2
45 Reviews

(Reviews last updated: August 2026)

What customers like about LG S12ER?

  • Efficient energy usage due to the built-in Smart Inverter technology
  • Rapid room cooling capability, especially when deploying the high-powered performance modes
  • Extremely quiet indoor unit operation, measuring around 30 decibels on lower settings
  • Versatile functionality offering dedicated cooling, dehumidification, and heat-pump heating
  • Convenient user features such as Comfort Air airflow diversion and an auto-cleaning cycle

What customers dislike about LG S12ER?

  • The physical remote control lacks a backlight, making it difficult to operate in dark rooms
  • Requires an optional separate hardware purchase or setup to unlock full Wi-Fi smart control functionality
  • The outdoor compressor unit can become noticeably louder when running at maximum capacity

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