LG’s Therma V range of air source heat pumps offers excellent efficiency and advanced technology for UK homeowners.

There are several models in the Therma V range: the Hydrosplit, Split – Low Temperature, Split – High Temperature and Monobloc.

We’ll start by looking at the Therma V R32 Hydrosplit, described by LG as ‘simple’ and ‘safe’. The system comes in outputs of 12kW, 14kW and 16kW and two different indoor unit options: a wall-mounted Hydro Box and a floor-standing Hydrosplit IWT (indoor unit + water tank). The Hydrosplit IWT features an integrated water tank, so there’s no need to install a separate one. This model only requires water piping indoors, making it safer than alternatives that require indoor refrigerant piping.

Perfect for new-build homes, the Therma V Split – Low Temperature is LV’s recently updated model that features a sleek new exterior design for the Hydro Box indoor unit and upgraded functionality. There’s also an updated IWT indoor unit available with this pump. A highlight of the Low Temperature Split is its user-friendly interface, which features a 4.3-inch colour LCD display, a glass front case and a reactive touchscreen LED panel. Like other models in this range, the Split – Low Temperature offers a Seasonal Auto Mode, enabling smart heating and hot water operation based on the outside temperature.

The Therma V Split – High Temperature offers reliable performance and high capacity, even at low temperatures. This makes it suitable for older, less-insulated properties and refurbishment projects. It can provide 80°C hot water and heating in temperatures as low as −15°C and 75°C down to −20°C. The external unit can be installed up to 10 meters from the home itself, providing greater flexibility during installation.

The Therma V R32 Monobloc is available in outputs of 3kW to 16kW, making it suitable for most homes. This is an all-in-one outdoor unit, meaning you won’t need to install another inside your house. This makes the Monobloc a good option for homes with limited indoor space. This model offers a number of features that help you save money, including LG’s Revolutionary Scroll Compressor, which improves overall reliability and efficiency.

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Technical information

  • Guarantee options: Seven years
  • Price range: From £3,255 to £6,300
  • Efficiency: A+ to A+++
  • Max power: 16kW

LG Therma V air source heat pumps demonstrate the latest in efficiency and smart technology, helping your home to become four times more energy efficient.

There are several models in the Therma V range, including:

  1. Split — Low Temperature
  2. Split — High Temperature
  3. Hydrosplit
  4. Monobloc

Each model has different specs as well as unique benefits, so you can select a heat pump that’s suitable for you and your home.

Split – Low TemperatureSplit – High TemperatureHydrosplitMonobloc
Refrigerant typeR32R410AR32R32
Heating capacity kW5.5, 7, 91612, 14, 165, 7, 9, 12, 14, 16
Minimum operating temperature−25°C−20°C−25°C−25°C
Maximum flow temperature (heating)65°C75°C (80°C down to −15°C)65°C65°C
ErP efficiency rating (heating)A+++A+A+++35°C: A+++ 55°C: A+
Dimensions (h x w x d) of outdoor unit (mm)834 x 950 x 3301,380 x 950 x 3301,380 x 950 x 330907 x 1,239 x 404
Dimensions (h x w x d) of indoor unit (mm)850 x 490 x 315 (Hydro Box) 1,810 x 602 x 680 (IWT)1,080 x 520 x 330850 x 490 x 315 (Hydro Box) 1,812 x 601 x 685 (IWT)n/a

Key features

  • Highlights: Up to four times more energy efficient than traditional fossil fuel boilers, helping you save money and reduce your carbon footprint.
  • Key benefit: The range offers several advanced features, including an emergency operation feature to ensure continual heating if something goes wrong with the unit, user-friendly controls, individual heating control zones and smart sensor capabilities to optimise energy usage.
  • Maximum flow temperature:
    • Split – Low Temperature, Monobloc and Hydrosplit: 65°C
    • Split – High Temperature: 80°C
  • Minimum temperature:
    • Split – High Temperature: −20°C
    • Split – Low Temperature, Monobloc and Hydrosplit: −25°C

Pros and cons

Every air source heat pump has unique advantages and disadvantages. Installing a new home energy system is a large investment, so you need to ensure you’re making the right choice. The LG Therma V air source heat pump range has the following pros and cons.


  • High efficiency: Three LG Therma V heat pumps have an energy efficiency rating of A+++. This range is up to four times more energy efficient than traditional heating alternatives that use fossil fuels.
  • Low carbon footprint: The LG Therma V uses just 25% electricity as it receives the rest of the energy it requires from the air outside, reducing your home’s carbon emissions.
  • Low maintenance and long lifespan: The LG Therma V can last up to 20–25 years if maintained properly.
  • Low-temperature tolerance: This range of air source heat pumps operates at low temperatures of −20°C to −25°C.
  • Automatic compensation: The system will monitor the temperature and adjust its operation to compensate for weather conditions, reducing your heating bills.
  • Emergency operation feature: If anything goes wrong, heat production will continue until it can be fixed so that you can continue to be comfortable in your home.
  • User-friendly controls: This range features a user-friendly interface that enables easy scheduling and monitoring. The ThinQ app enables homeowners to manage their heating and hot water remotely, no matter where they are.


  • Nothing of note

How do LG Therma V air source heat pumps work?

A diagram showing how the LG Therma V air source heat pumps provide heating and hot water for a house.

The LG Therma V range of air source heat pumps can provide heating and hot water even at temperatures as low as −25°C. (Image credit: LG)

The LG Therma V range of heat pumps absorbs natural energy from the air and compresses it to provide your home with heating and hot water. According to LG, this range is up to four times more energy efficient than traditional fossil fuel-reliant boilers. Every 1kWh of electricity the heat pump needs to run generates 2–4kWh “for free” from the air.

Three of the products in this range feature both outdoor and indoor units, but the R32 Monobloc is an all-in-one outdoor unit only. These heat pumps work with radiators and underfloor heating, and they can connect to solar panels with an added accessory.

Therma V heat pumps feature LG Inverter Technology. Being inverter-controlled means they can adapt to demand and only use the energy necessary to perform, making them highly efficient.

With the ThinQ app, you can take control of weekly scheduling, water temperature, emergency heating operation and operating volume.

How do the LG Therma V air source heat pumps compare to others?

The LG Therma V is one of the best air source heat pump ranges on the market. With outputs as high as 16kW, Therma V heat pumps can power most homes, while the more compact all-in-one units are perfect for flats and small properties.

If the outdoor temperature where you live drops very low, this range is a good choice for you as the heat pumps operate down to −20°C and −25°C. You could also consider the Daikin Altherma 3. This compact and powerful heat pump can also operate in low temperatures of −25°C. This model comes in at around £8,000 and only comes with a five-year warranty, however.

If you need more power to heat your home and you’re less concerned about your heat pump operating in low temperatures, consider the Vaillant flexoTHERM 400V. This heat pump’s maximum output is 19kW, ideal for larger homes. Despite its high power output, the flexoTHERM 400V is reportedly one of the quietest models on the market, causing minimal sound disruption.

If you’re a fan of the monobloc all-in-one style, consider Mitsubishi’s range of Ecodan monobloc air source heat pumps. They come in power outputs ranging from 4.5kW to 14kW and have ErP energy efficiency ratings of A+++. A downside to consider is that Mitsubishi only offers a five-year warranty, which is shorter than LG’s seven-year warranty for the Therma V range.

How much do LG Therma V air source heat pumps cost?

The LG Therma V range is very reasonably priced, despite its high efficiency levels and powerful outputs. Here is how it compares to other air source heat pumps on the market:

Manufacturer and productCost (excluding installation and labour)
Daikin Altherma 3From £6,000 to £10,000
LG Therma V rangeFrom £3,255 to £6,300
Mitsubishi Ecodan monobloc rangeFrom £2,600 to £5,815
Vaillant flexoTHERM 400VFrom £7,634

Maintaining your LG Therma V air source heat pump

The LG Therma V range of air source heat pumps doesn’t require much maintenance, but a thorough annual service is recommended, especially before winter.

In general, we recommend making sure that the unit is free from debris and obstruction. Turn off the fan and examine the blades and coil regularly to make sure that it is free from dirt, dust and organic material from the garden (for outdoor units).

LG Therma V air source heat pump add-ons

If you would like your air source heat pump to connect to your solar panels, you can add an accessory to enable this functionality. Ask your installer for their advice.

What the professionals say

A twin fan LG Therma V air source heat pump installed outside a house with snow on the ground.

LG Therma V air source heat pumps have been praised for their efficiency even in below-freezing temperatures. (Image credit: LG)

“LG has developed a range of flexible air source heat pumps that are run by renewable energy to offer you a highly efficient and cost-effective way to generate hot water and heat your home. The brand’s air-to-water heat pumps are not only reliable and durable but can also reduce your household’s carbon footprint and lower your heating bills, meaning you can do your bit for climate control and keep more of your hard-earned cash in your wallet. If you want to power your home with renewable energy and are thinking of investing in an air source heat pump, LG could have the perfect system for you.”

“If you live in below-freezing conditions, it’s a massive relief not to have to go outside and fix the heating when it’s dangerously cold. Fortunately, even though heat pumps work by absorbing warmth from the air outside, LG’s best model is still able to function happily at temperatures as low as −25°C. So when the snow and icy winds sweep in at full power, you can wrap up with a hot drink, safe and comfortable in the knowledge that your heat pump will keep you warm.”

“LG Therma V heat pump offers a good level of heat and works efficiently even at temperatures as low as −15 C without additional heating sources. LG heat pumps are durable products with a long lifespan. Also, the heat exchangers are processed in such a way that they are protected against corrosion and pollution.”

Customer reviews

“It is claimed that LG heat pumps operate ‘efficiently’ at −25ºC. They do not. The general climate here [near Taunton, not on Exmoor!] is pretty mild. This year [2022] for example the temperatures recorded here did not fall below −4ºC and only touched −4º briefly. The daytime temperature required in the house is 20ºC. When the outside temperature is +5ºC or lower the house temperature never reaches the target 20ºC. I want the heat when it is cold. The warmer the outside temperature is, the easier it is for the heat pump to raise and maintain the inside temperature to the required 20ºC. But at +5ºC or below the LG Therma V seems incapable of recovering sufficient heat. I have no idea whether this is because LG Therma V heat pumps are rubbish or whether the set-up here is wrong. In spite of bringing this to the attention of LG they have failed to do anything to remedy that, as well as failing to respond to my complaint.”

“I have an LG 7kW Therma V. I have had it for just over one year. The total kW used from 19th Dec 2020 to 19th Dec 2021 was 4,058kW. We use the heating all day in winter as we are retired and like to be warm. I have had no problems with the heat pump and it has just had its first service.”

Final recommendation

LG’s range of Therma V air source heat pumps provides heating and domestic hot water for residential homes. There are four models available in several outputs, with a maximum output of 16kW. Each model has different features and benefits, so you’re sure to find a unit type that suits your home and requirements.

There’s a significant focus on user experience, and the newly updated Split – Low Temperature model features a user-friendly LED display that makes controlling and monitoring your heat pump a breeze. What’s more, the heat pumps boost your home’s energy efficiency through intelligent seasonal heat adjustment.

These air source heat pumps can function perfectly well at temperatures as low as −20°C to −25°C, while the emergency heating operation gives you peace of mind should the unit develop a major fault. These features, along with LG’s lengthy warranty of seven years, make the LG Therma V a good choice for most homes.


To provide this LG Therma V air source heat pump review with impartial, accurate information, we read online customer reviews from sites like Google and Trustpilot, professional forums and technical documentation. We also considered the opinions of professionals to see if they recommend the product. 

We then compiled a 100-point scorecard to rate the LG Therma V against, consisting of the following criteria:

  • The warranty period offered by the brand, for a total of 10 points;
  • The overall reputation of the brand based on online reviews, for a total of 15 points;
  • Trustpilot reviews, for a total of five points;
  • Awards and accolades (eg, Which? Best Buy Awards), for a total of five points;
  • Customer service performance, for a total of 10 points;
  • The price range, for a total of 15 points;
  • Efficiency ratings, for a total of 15 points;
  • Installation and maintenance network and reviews, for a total of 15 points; and
  • The total warranty period, for a total of 10 points.