Air source heat pump – Operating principle, applications and comparison with other heating methods (2025)

Table of contents

1. Introduction to air source heat pumps

2. The operating principle of an air-source heat pump

3. Intended uses
   

4. Suitable applications
   

5. Comparison with other forms of heating
   

6. Well-known manufacturers and most popular models in Finland 2025
   

7. Summary and recommendations for different needs
   
   

Introduction to air source heat pumps

What is an air source heat pump?

An air source heat pump (ASP) is a device that transfers heat energy from the outside air to the inside air for heating, and if desired, also in the opposite direction for cooling. In simple terms, an ASP “pumps” heat : in winter it collects heat from the outside air and transfers it to the inside air, while in summer the device can be set to cool, transferring heat from the inside to the outside. A typical ASP consists of two parts: an outdoor unit installed on the outside wall of the building and an indoor unit installed inside, which are connected by refrigerant pipes. The outdoor unit contains the compressor component of the device and the cell responsible for collecting heat; the indoor unit, in turn, blows warm (or cool) air into the room.

Air source heat pump and energy efficiency

The popularity of air-source heat pumps has grown strongly due to their energy efficiency. There are already over a million air-source heat pumps in use in Finland, which indicates that the technology has become an established heating solution for households. More and more detached houses and cottages are equipped with air-source heat pumps, because the device can significantly reduce heating costs. An air-source heat pump brings savings from the first day of use: a well-designed system can typically cover 30–60% of a building's annual heating energy needs. Compared to electric heating, a heat pump can produce the same heat at least 2–3 times more energy-efficiently , so the payback period for the device is often only a few years. For example, the seasonal coefficient of performance (SCOP) of a modern air-source heat pump can be around 5, which can reduce heating electricity consumption by up to 70% compared to direct electricity. At the same time, using an air-source heat pump reduces the carbon footprint of housing: adding a heat pump to support an existing heating system can reduce heating CO₂ emissions by 20–40% annually.

Air source heat pumps are therefore purchased primarily for energy savings and comfort . The device provides affordable heat in winter and, if necessary, functions as an air conditioner in summer. A relatively small investment can improve living comfort all year round, which has increased the popularity of the devices in both new and old buildings. The following chapters will take a closer look at the operating principle of the air source heat pump, its application possibilities in different locations, and compare the air source heat pump to other forms of heating. In addition, the popular air source heat pump models in Finland in 2025 are presented and a summary is provided with recommendations for different needs.

Principle

How does an air source heat pump work?

The operation of an air-source heat pump is based on the thermodynamics of a refrigeration system . The core of the device is a closed refrigerant circuit in which a heat-binding and heat-releasing substance circulates. The most important components of the system are a compressor, two heat exchangers (one in the outdoor unit, the other in the indoor unit) and an expansion valve. The compressor's task is to circulate the refrigerant and change its pressure. The compressor's electromechanical work compresses the refrigerant, causing its pressure and temperature to rise significantly. The hot, high-pressure refrigerant is led to the indoor unit's cell (condenser), where it cools and condenses into a liquid, releasing thermal energy into the room air with the help of a fan. The liquid refrigerant then passes through the expansion valve to the outdoor unit's cell (evaporator). The expansion valve reduces the pressure of the refrigerant, causing it to evaporate strongly and its temperature to drop. The outdoor unit's cell is flushed with outdoor air using a fan, and as the refrigerant evaporates, the cell absorbs heat from the outdoor air. In the final stage, the compressor sucks this refrigerant vapor back in and the process repeats itself in a continuous cycle. This is how the heat pump transfers heat from the outdoor air to the indoor air.

Technical principle: A heat pump uses phase changes of matter (from liquid to gas and back) to transfer heat. When the refrigerant evaporates, it binds a large amount of energy (latent heat) and when it condenses, it releases the same energy. The phenomenon is comparable to the evaporation and condensation of water: for example, the coolness of wet clothes on the skin is due to the fact that the evaporation of water binds heat from the environment. An air-source heat pump uses electrical energy only to run the compressor and fans – the heat energy itself is not generated by an electrical resistor, but existing heat is recovered from the environment . Therefore, the efficiency of an air-source heat pump (COP, Coefficient of Performance) is typically 2–4, i.e. one kilowatt of electricity produces 2–4 kW of heat indoors. The seasonal coefficient of performance (SCOP) of the device takes into account the varying conditions throughout the year; the best current models reach SCOP values ​​of around 5.

It is important to note that the performance of a heat pump varies depending on the outdoor temperature . The colder it is outside, the greater the temperature difference the device has to create, which reduces the efficiency. For example, the nominal output and COP value indicated at an outdoor temperature of +7 °C are reduced by about half when the outside temperature is -20 °C below zero. In the most severe frosts (close to -30 °C), the efficiency of an air-source heat pump can approach the level of direct electric heating. Nowadays, the energy labels of heat pumps indicate the SCOP value (Seasonal COP) for cold climates, which gives a more realistic picture of the annual efficiency of the device in northern conditions than the COP figure alone. For this reason, the air-source heat pump is sized and used so that it does not have to run at full capacity all the time – the efficiency is better at part load. In a well-insulated house and in mild weather, the pump can operate more energy-efficiently than in a poorly insulated building or in severe frosts. Often, an air-source heat pump is installed to support another heating system, so that during the coldest periods, additional heat (e.g. electric radiators or a fireplace) can be used to support the pump if necessary.

The components of an air source heat pump form a closed system that usually does not require intervention by the user. The compressor and the outdoor unit fan are located outdoors in a sealed unit that circulates outdoor air for heat collection. The indoor unit is usually installed high on a wall in a large room, from where its fan distributes heat or cool air to a wide area. The indoor unit also has an air filter that cleans the recirculated room air of dust and impurities. The filter must be cleaned regularly to maintain sufficient airflow and good air quality. Modern air source heat pumps also have electronics and automation that control the compressor speed (inverter technology) and optimize the defrost cycles in the outdoor unit. This ensures the most consistent and efficient operation in different conditions.

The indoor unit of an air source heat pump is usually a wall-mounted device that blows warm or cool air into the room. The indoor unit contains a heat exchanger coil (condenser in heating mode), a fan and an air filter.

In summary, the operating principle of an air-source heat pump can be stated as follows: the device uses a refrigerant to transfer heat from outside to inside (or vice versa) by utilizing the work done by the compressor. This method of operation, also known as the refrigerator principle, enables significantly more efficient heat generation than traditional electric heating elements. As technology has developed, the efficiency of air-source heat pumps has improved even further, and new environmentally friendly refrigerants (such as R32) have reduced the climate impacts of the devices – the greenhouse emissions of the R32 refrigerant are up to 67% lower than those of the old R410A. Efficient utilization of an air-source heat pump requires proper sizing, installation location and use: an open floor plan enhances heat distribution, and automatic adjustments (e.g. night settings, temperature drop) help keep consumption under control. When installed and maintained correctly, an air-source heat pump is a reliable, safe and long-lasting (typical service life is 15–20 years) heating and cooling device.

Intended uses

An air source heat pump is a versatile device that can be used for heating, cooling and improving indoor air quality . The following are the main uses of the pump:

• Heating: The primary purpose of an air source heat pump in Finland is to heat a building. In winter, the device produces even heat and maintains a pleasant room temperature in an energy-efficient manner. The pump reacts to changes in the indoor temperature with thermostat control and is able to produce heat even in severe frosts, as long as it is assisted by backup heating if necessary. An air source heat pump is generally not recommended as the only heating system, but when used correctly, it covers a large part of the heating requirement and significantly reduces the energy consumption of, for example, an electric heater. A good air source heat pump can produce all the heat needed by a building during a mild winter, but on the coldest days, another heat source is needed as a backup. In models equipped with an automatic function, it must be ensured that the device does not switch to cooling unnecessarily, for example when heating a fireplace - it is often better to use heating mode only manually during the winter season.
  
  

• Cooling: Increasingly, air-source heat pumps are also used as air conditioners in summer heat. The same device that heats in winter can be used to cool a home effectively in summer. With the cooling function, the process is reversed: the indoor unit's cell acts as an evaporator, which cools the room air, and the outdoor unit blows the heat energy out. Air-source heat pump cooling is usually significantly more energy-intensive than old-fashioned window-type air conditioners; the pump transfers heat out with an efficiency of a few COP units. The typical electricity consumption of the cooling function is quite low and does not significantly eat into the savings achieved during the heating season. As a side effect of cooling, the device also removes moisture from the indoor air, which increases living comfort in hot weather. This is important, because excessive indoor humidity can feel uncomfortable - the air-source heat pump also acts as an effective dehumidifier in summer.
  
  

• Air purification and exchange: An air source heat pump circulates room air through filters , which cleans the indoor air of dust, pollen and other particles. The indoor unit of the device usually has a washable dust filter, and some models also have activated carbon or ionization filters that improve air quality. For example, Panasonic models have Nanoe X technology, which neutralizes impurities and odors from indoor air. However, it should be noted that a traditional air source heat pump does not replace actual ventilation , as it does not bring fresh air from outside into the room, but circulates existing indoor air. Some newer models may have a limited air inlet, but the ventilation effect of the ILP is mainly based on air mixing and filtering. In any case, cleaner and moving indoor air increases comfort. Careful placement of the device can also even out temperature differences from room to room in apartments, which improves overall efficiency (e.g. by blowing heat into the staircase, it spreads upstairs).
  
  

• Energy saving: The main reason for using an air source heat pump is to save energy and costs . When an ILP is installed in a house with direct electric heating, for example, the electricity bill can be reduced by 20–30% during the heating season. Correspondingly, the oil consumption of an oil-heated house is significantly reduced when part of the heat is produced by an air source heat pump. The heat produced by the device is so-called “free energy” insofar as it comes from the environment – ​​only the electricity used by the compressor and fans is paid for. In practice, a well-sized pump can produce savings of hundreds of euros per year in heating costs. The investment in an air source heat pump (purchase price and installation) usually pays for itself in about 5–7 years in energy savings alone. After this, the device continues to produce net benefits throughout its remaining lifetime. In addition to saving energy, using a heat pump reduces the need to burn wood in the fireplace or use electric radiators, which can increase the convenience of living and keep the indoor temperature more even.
  
  

In summary, an air source heat pump is a multifunctional device that increases living comfort in all seasons. It offers an economical heating solution for winter, relief on hot summer days by cooling, and improves indoor air quality by filtering pollutants. These benefits are achieved in an environmentally friendly way: the heat pump utilizes renewable energy (outdoor heat) and thus reduces the building's carbon dioxide emissions compared to traditional heating methods. An air source heat pump works best as a partner to an existing heating system – it is a flexible solution that can be integrated into a variety of applications, from the main heating of detached houses to the maintenance heating of summer cottages or the cooling of office spaces.

Suitable applications

Air source heat pumps are suitable for many different applications and building types. One of the advantages of ILP is that it is relatively easy to install in almost any building – it does not require extensive modifications to the building's structures. The following is a review of typical applications for which an air source heat pump is suitable:

• Single-family homes: Most air-source heat pumps are installed in small houses, especially in electrically heated single-family homes. In such houses, ILP significantly reduces heating electricity consumption. In open-plan single-family homes, one indoor unit can spread heat over an area of ​​30–100 m². If the house has a maze-like layout or is two-story, several indoor units (multi-split system) can be considered to cover the entire living area. An air-source heat pump is usually not enough on its own as the only form of heating in a house, but it is an excellent supplementary heating option alongside electric heating, an oil boiler or even a pellet stove. Many single-family homeowners also consider the cooling option a big plus. In a single-family home, the pump's outdoor unit can easily be placed on the wall of the house or on a sturdy ground support above the snow line (at least ~80 cm above the ground).
  
  

• Terraced houses and apartment buildings: Residents of terraced houses and apartment buildings have also started to install air source heat pumps (or rather air conditioning pumps) in their apartments, although mainly for cooling . In apartment buildings, the use of an air source heat pump for heating is often not necessary (since the houses are usually connected to district heating), but ILP has been in demand as an apartment-specific cooling device, especially on the upper floors. Installation requires permission from the housing company, as the outdoor unit has to be attached to the facade or balcony. Many housing companies have allowed modern, quiet devices because they significantly improve living comfort in the summer heat. In terraced houses with more private wall space, installing an ILP is easier and it can be used for both heating and cooling, depending on the size and layout of the apartment. It is worth noting that an air source heat pump is not compatible with central ventilation in the sense that it does not distribute heat in the ventilation ductwork – each apartment uses its own indoor unit.
  
  

• Summer cottages and holiday homes: An air source heat pump is a very popular heating solution for cottages , especially for maintenance heating in the winter. The basic temperature in a cottage can be kept at, for example, +10 °C with the help of an ILP in winter, which prevents cold moisture condensation on the structures and makes it easier to use the cottage for holidays. The device often has a maintenance temperature setting (e.g. +8…+12 °C), which keeps the cottage warm in an energy-efficient way. When you arrive at the cottage, the temperature can be raised quickly by increasing the pump's power. In summer, an air source heat pump helps keep the cottage cool on hot days. Since many cottages do not have an electrical connection rated for high heating, an ILP is a great solution: it consumes only a little electricity when producing heat. The remote control option is also appreciated in cottage use – many models can be controlled with a phone app, so you can raise the temperature to a comfortable level already on the way to the cottage. Please note that when installing in a cottage, the outdoor unit should be placed out of reach of snow loads and falling ice (e.g. under the eaves).
  
  

• Garages and outbuildings: An air source heat pump is also well suited for heating garages, warehouses and other outbuildings . Especially in spaces where the need for basic heat is moderate and continuous, ILP offers an inexpensive way to keep the temperature on the plus side. In a garage, a temperature of around +5…+15 °C is often desired so that the car and belongings stay dry – an air source heat pump is well suited for this task. It works excellently as such a main heating system in smaller spaces. Installation is simple, as a separate water-circulating radiator network or chimney is not required. Many heat pump models can withstand cool maintenance operation very well and their technical operation is not disrupted, even if the space to be heated is only a few degrees warmer – although the efficiency is better when a slightly higher temperature is maintained. For outbuildings, ILP also benefits from cooling: for example, the dressing room of an outdoor sauna or workshop can be cooled in the summer if necessary, if they are occupied.
  
  

• Business premises and commercial premises: Small offices, shops, cafés and other commercial premises make extensive use of air source heat pumps for both cooling customer premises and energy-efficient heating. Especially in premises where there is no district heating or where independent cooling is desired, ILP is a cost-effective solution. In commercial premises, the pump's ability to react quickly to fluctuations in heat loads is valued - for example, the scorching sun or an increase in the number of customers raises the indoor temperature, in which case the inverter-controlled pump automatically increases its output. Similarly, in the evenings and at night, when the premises are empty, the heat pump can be set to standby mode to save energy. Many entrepreneurs also choose an air source heat pump because it improves indoor air quality (dust filtration) and reduces draft compared to electric fans. Server and equipment rooms are one special example: an air source heat pump is a common solution for cooling small server rooms all year round.
  
  

In general, it can be said that an air source heat pump is suitable for all types of buildings that have an available electricity connection and a need for either increased heating or cooling. It does not require water-based heat distribution (such as radiators or underfloor heating), which makes it particularly attractive for renovation projects where the heating system needs to be improved without major renovations. ILP also brings much-needed relief in electricity consumption to apartments with direct electric heating (radiators or ceiling heating). The only sites for which a traditional air source heat pump is not directly suitable are those where the heating need is very small or non-existent (e.g. cold storage facilities that are deliberately kept at freezing temperatures) - but even in these cases, an ILP could maintain a small amount of heat if necessary. Overall, an air source heat pump is a flexible and scalable solution, which explains its popularity from single-family homes to apartment buildings and commercial buildings.

Comparison with other forms of heating

An air source heat pump represents a heat pump technology that utilizes renewable heat from the environment (outdoor air) for heating. It can be compared to both traditional direct heating forms (electricity and oil) and other heat pumps (e.g. geothermal) and district heating. The following compares the air source heat pump to these alternatives in terms of cost, efficiency and environmental impact.

• Direct electric heating: Conventional electric heating – such as electric radiators, ceiling heating or underfloor heating cables – converts electrical energy into heat with an efficiency of 1 (100%). In contrast, an air source heat pump uses 1 kWh of electricity to transfer several kWh of heat from the outside to the inside, so its efficiency is many times higher . As previously stated, an ILP can typically reduce the energy consumption of an electric heater by ~30–60% depending on the situation. This means significant cost savings, especially when the price of electricity is high. The advantage of direct electric heating is the low price of the equipment and the freedom from maintenance, but the operating costs are high. An air source heat pump requires an initial investment (approximately €1,500–3,000 installed), but pays for itself in reduced electricity bills within a few years. From an environmental perspective, direct electric heating produces emissions depending on the electricity production – in Finland, electricity is increasingly cleaner, but because electric heating consumes a lot of kWh, its carbon footprint is larger than that of an ILP, which significantly reduces the need for electricity . On the other hand, an electric radiator always operates at rated power even in severe frosts, while the power of an air-source heat pump decreases as the frost increases. Therefore, direct electricity works well as a backup heating system alongside ILP. In practice, ILP is almost always a profitable addition to a direct electric heater: it offers the same comfort with much lower energy consumption.
  
  

• Oil heating: A house heated by an oil boiler with a water circulation system can also be equipped with an air-to-air heat pump. The efficiency of oil heating is usually ~85–90% (boiler efficiency), and fuel oil is a fossil fuel that produces carbon dioxide emissions when burned. Adding an air-to-air heat pump directly reduces the amount of oil needed. Fuel costs : One liter of fuel oil produces about 10 kWh of heat, so if the price of oil is, say, €1/l, the price of a kilowatt-hour of heat will be ~€0.10. If the price of electricity fluctuates (e.g. €0.15/kWh), the price of heat produced by an air-to-air heat pump could be ~€0.05/kWh (COP=3) – clearly cheaper than oil. The rise in oil prices and taxation make the heat pump even more attractive. Environmental impacts : Oil heating produces about 260 g CO₂ per kWh of heat produced, while the electricity used by an air-to-air heat pump in Finland has much lower emissions on average. With a heat pump, an oil-fired heater can reduce the carbon dioxide emissions of its home by up to 20–40%. In addition, the service life of the oil boiler is extended when it is less stressed. Air-to-air heat pumps are a popular solution in oil-fired houses before switching to fully renewable heating systems. The disadvantage is that the oil boiler still needs to be kept in working order as a backup – but the pump handles the base load for a large part of the year. Compared to oil heating, ILP also improves indoor air (no combustion gases inside) and reduces dependence on oil price fluctuations.
  
  

• Geothermal heat (ground source heat pump): A ground source heat pump works on the same principle as an air source heat pump, but it collects heat from the ground or rock through a borehole. A ground source heat system is a comprehensive heating solution that usually covers the heating of the entire house and the production of hot water. The investment cost is high (typically €10,000–20,000 including drilling), but the efficiency of a ground source heat pump is excellent all year round – the annual coefficient of performance (SCOP) is usually 3–4 in northern conditions, meaning it saves up to 60–75% electricity compared to direct electric heating. Ground source heat is therefore even more energy efficient than an air source heat pump, especially during the coldest times of winter, because the borehole temperature remains higher than the outside air. The operating costs of ground source heat are very low (mainly electricity price x 1/3 kWh per kWh of heat). In terms of environmental impact, ground source heat is a very good choice: it reduces CO₂ emissions from heating dramatically, especially when the electricity production is renewable. In terms of ease of use, geothermal heat is equivalent to traditional central heating – the system is discreet and fully automatic. Compared to an air-source heat pump, a geothermal heat pump does not affect the indoor air circulation (ground heat is connected to water-circulating floor or radiator heating). If the house already has a water-circulating heating system, geothermal heat can be a good solution to replace it. But if there is no water circulation (only electric radiators), an air-source heat pump is significantly cheaper to install. In summary: geothermal heat is a large investment, but in the long run it is the most efficient and environmentally friendly form of heating. An air-source heat pump is cheaper and more flexible, but usually only covers part of the heating.
  
  

• District heating: District heating is the most common form of heating in many cities, where hot water produced in a centralized plant is distributed through a network of pipes to the heat exchangers in buildings. District heating is an easy and worry-free solution for the user: it does not require its own equipment (except for the heat exchanger) or fuel refills. The costs consist of a connection fee and a consumption-based tariff. Compared to an air-source heat pump, district heating is consistently reliable – its output does not depend on the outdoor temperature and heat is always available as needed. The efficiency of energy production is high, because district heating often uses cogeneration (electricity and heat are produced in the same process) or waste heat. The environmental impacts depend on the method of heat production: in Finland, district heating is still partly fossil (natural gas, coal), but there is an increasing shift to biofuels, heat pumps (e.g. large regional heat pumps) and even nuclear energy (small reactors in the future). An air source heat pump does not usually compete with district heating, because if the house is already on district heating, it does not make economic sense to use a separate heat pump for heating. The exception is cooling : in a district heating house where cooling is needed, the solution may be to install an air source heat pump for cooling only. District heating is reliable and relatively environmentally friendly in large urban areas, but it is not available in sparsely populated areas. There, an air source heat pump is often an easy and affordable option if you do not want to invest in geothermal heating. Compared to district heating, the advantage of ILP is precisely the cooling option and the fact that the customer controls their device themselves (they are not as dependent on price increases from the energy company).
  
  

• Air-to-water heat pump: Although this was not specifically asked, another type of heat pump is worth mentioning, the air-to-water heat pump (IVLP) , which collects heat from the outside air like an ILP, but transfers it to a water-circulating heating system. An IVLP is a kind of intermediate form between an air-to-water heat pump and a ground-source heat pump. It can also heat domestic water and the entire house's water-circulating network, but its output decreases when the outside temperature drops in the same way as an ILP. The investment is higher than an air-to-water heat pump, but lower than a ground-source heat pump. The environmental impact and savings are good, but in the most severe frosts, an IVLP needs an electric heater to help. We mention this because sometimes the terms can be confused: an air-to-air heat pump usually refers to an air-to-air pump (ILP), which is what this report is about, while an air-to-water pump is a separate device.
  
  

A summary of the comparison of different heating methods is presented in the table below. It shows the typical characteristics of each option in terms of cost, efficiency and environmental impact:

Table 1: Comparison of different heating methods (air source heat pump vs. alternatives)

(The prices and figures in the table are indicative average values ​​for 2025. Figures may vary for individual properties.)

The table shows that the air source heat pump is in a sort of intermediate position: as an investment it is cheaper than geothermal or air-to-water pumps, but in terms of efficiency it is better than direct electricity or oil. It is also a flexible form of additional heating, as the ILP can be installed as a parallel system in almost any house. Compared to other heat pumps, its weakness is its inability to produce all the heat all year round – in severe frosts, a second heat source is needed to help it. In terms of cost, the ILP is often a “low-hanging fruit”: with relatively low costs, a large part of the heating energy is recovered from the environment. From an environmental perspective, every kilowatt-hour produced with a heat pump instead of direct electricity or oil is a win – heat pumps utilize renewable heat and significantly reduce emissions.

However, there are situations where another form of heating may be more justified: For example, in a new house in the middle of the city, district heating may be the most economically sensible, or in very large buildings, geothermal heat may produce the lowest operating costs. Often, a solution can also be found in combinations, such as hybrid systems (ILP + electricity, ILP + fireplace, ILP + oil). From the perspective of living comfort, the cooling potential provided by an air-source heat pump is unique compared to, for example, oil or district heating – as heat waves become more common, this also weighs in the balance.

Well-known manufacturers and popular models in Finland 2025

In 2025, air source heat pumps from several manufacturers will be available on the Finnish market, some of which have established themselves as reliable quality brands and some represent newer entrants. The most popular brands in the Finnish air source heat pump market include Mitsubishi Electric , Panasonic, Toshiba , Daikin and traditionally Fujitsu . In recent years, Chinese manufacturers, such as Gree and Midea (Innova) , have also increased their popularity in the more affordable price range by offering models suitable for Nordic conditions. Below, each of the best-known manufacturers and their popular models are briefly discussed, and their features, price levels and consumer reviews are compared. A detailed comparison is presented in the table at the end of the report.

Mitsubishi Electric: Mitsubishi has long been one of Finland's best-selling air source heat pump brands, known for its excellent energy efficiency and ability to operate reliably even in severe frosts. In particular, models that utilize Mitsubishi's Hyper Heating technology, such as LN series (MSZ-LN) and later The FT series have been perennial favorites. In these devices, the nominal heating output remains good even at -25 °C and the reliability extends to -35 °C. Mitsubishi models usually come standard with Wi-Fi remote control and a so-called fireplace function , which circulates the heat from the fireplace throughout the house with a blowing function. Consumers appreciate Mitsubishi Electric pumps for their reliability, efficiency and ease of use – user reviews repeatedly praise the device's efficient heating capacity in winter frosts and quiet operation. Mitsubishi's price range is mid-high; typically installed pumps cost around €2,000–3,000, but in return you get top quality and a long service life. The brand is also known for its extensive service network in Finland, which provides security for a long time.

Panasonic: Panasonic is another Japanese quality brand that is very popular in Finland. Panasonic's HZ series "Flagship" models and the basic CZ/XZ series (in the Etherea range) have established themselves in many homes. Panasonic's devices are known for their quiet operation and top-class air filtration capabilities - for example, the Nanoe X ionizer is used in many models to purify indoor air. Panasonic's best models in terms of power also reach operating temperatures of -25 °C and SCOP values ​​are around 5, meaning they receive an A+++ energy rating. In consumer feedback, Panasonic is particularly praised for its sound characteristics: the sound level of the indoor unit can be only ~19 dB(A) at the lowest power, which makes the device almost imperceptible. The price level is mid-range: around €1,500–2,500 when installed, depending on the model. Panasonic's strengths also include a wide range - there are small models for apartment buildings and more efficient models for single-family homes. The environmental friendliness is demonstrated by the fact that the manufacturer has switched to R32 refrigerant in all its popular models, which further reduces the climate load of the device. Overall, Panasonic is a brand with excellent value for money : in the light of consumer reviews, it is still a very popular and reliable choice (many models receive 4–5/5 stars from users, for example for efficiency and finish).

Toshiba : Toshiba is also a well-known brand that has been manufacturing heat pumps for a long time. In Finland, Toshiba has made a special profile with models designed for Nordic conditions , such as the Daiseikai series . In 2025, Toshiba is launching its new 10th generation Daiseikai flagship model, which is expected to have top-notch performance. Already existing models, such as the Toshiba Polar and Premium+ , have gained popularity: they offer efficient heating even in severe frosts and very quiet operation. Toshiba uses advanced inverter technology to optimize the operation of the compressor, and the devices usually have Wi-Fi remote control as standard, like competitors. Toshiba also has a special focus on indoor air quality - for example, the AllergenClear and Plasma ionization functions in some models help allergy sufferers with cleaner air. In consumer reviews, Toshiba gets points for quietness and durability . Attention has also been paid to design: Toshiba offers indoor units that blend into the interior , and new models are even coming with wood-trimmed indoor unit options for the design-conscious. The price range is mid-to-high (approx. €1,800–2,500 installed, depending on the model). Toshiba has been chosen as a test winner in some Nordic comparisons due to its balanced performance. In consumer reviews, Toshiba pumps are generally classified as “very good” (approx. 4/5 stars), with particular mention of the device’s quietness and reliability in freezing temperatures.

Daikin: Daikin is a large international manufacturer that has also increased its market share in Finland in recent years. Daikin is known for its innovative solutions – for example, the new Nepura series air-source heat pumps have introduced unique features to the market. One of Daikin's specialties is the outdoor unit layout: in Nepura models, the defrost water from the outdoor unit can be directed directly to the drain via the base plate, which is not usually standard with other brands. Daikin also offers exceptionally long warranties for its devices when the customer registers the product – this shows confidence in quality. Popular models in 2025 are Daikin Stylish and Perfera (N series) , which represent stylish design (e.g. different color options for indoor units) and top-class energy efficiency. The Daikin Perfera N30 is classified as a top model in 2025 due to its excellent heating and cooling performance. It also has a built-in air purification function for allergy sufferers. User reviews of Daikin pumps emphasize the quietness and reliability of the devices – many also find Daikin's customer service and service network to be very good. In terms of price, Daikin is in the premium class alongside Mitsubishi (often in the €2,000–3,000 range). The company is one of the few that also has its own heat pump production in Europe (many others produce equipment in Asia). Overall, Daikin is an emerging favorite , especially for design- and quality-conscious customers.

Fujitsu General: Fujitsu (and its European brand name General ) is a long-standing heat pump manufacturer, with equipment installed in Finland since the 1990s. Fujitsu is known for its durable and high-quality pumps. In 2025, Fujitsu will continue to strive to remain among the top brands by renewing its range. In particular, Fujitsu Slim Excellence has been mentioned as a new product that offers efficient heating in a slimmer indoor unit size. Fujitsu's strengths include advanced inverter control , quiet operation and long service life. The devices are designed to operate in demanding conditions and many installers consider Fujitsu a "safe choice" due to its technical reliability. User reviews highlight the reliability and ease of use of Fujitsu pumps - the durability of the devices is praised, as is the support and service provided by the company. Fujitsu uses the same environmentally friendly refrigerants (R32) as other leading brands and is committed to improving energy efficiency. The price level is mid-range; Fujitsu's basic ILP model can be purchased installed for ~1500–2000 €, more powerful models for around 2000–2500 €. In Finland, Fujitsu may be a little less prominent in marketing than Mitsubishi or Panasonic, but its reputation as a "do-it-yourself" device lives on, especially among industry professionals.

Gree (and other new challengers): Chinese Gree is the world's largest air conditioning manufacturer, which has also made a strong entry into the Finnish market in recent years. Gree is known for its affordable but efficient devices. In 2025, Gree launched the new SP-X Nordic range, which is designed specifically for Nordic conditions with a larger outdoor unit and a two-stage compressor. This model offers exceptionally good heating performance at a more affordable price range – its heat output at outdoor temperatures of -15 °C and -25 °C is close to that of more expensive brands. Gree has also received a lot of attention for its Amber Nordic models, which have been tested to work down to -30 °C. Consumers have praised the price-quality ratio of Gree pumps : for a reasonable purchase price (around €1,200–1,800 with installation), you get a device that does almost the same as better-known brands. User reviews often mention Gree for its ease of use and efficiency, while the level of finish may not be as good as that of its Japanese competitors, but it is worth the price. Other Asian players, such as Midea , whose appliances are often sold in Finland under the Innova brand, also fall into the same category: they offer competitive options for budget-conscious customers. In 2025, these brands will be growing in popularity, forcing traditional manufacturers to keep their prices under control. It should be noted, however, that the scope of maintenance and spare parts services may be more limited for new entrants, but this will improve as they become more established.

To summarize the market review : consumers have a lot of choice. High-quality Japanese brands (Mitsubishi, Panasonic, Toshiba, Fujitsu, Daikin) offer top features, reliability and longevity at a slightly higher price. Newer players (Gree, Innova/Midea, etc.) provide more affordable options with basic functions and performance, although the reputation of the brands is still developing. All modern models have certain basic features as standard: inverter compressor, remote control or app control, automatic defrosting, multiple fan speeds and timer functions. The differences are mainly found in smart features, design, volume, and performance in extreme temperatures. The table below provides a comparison of some popular models and brands in 2025.

Table 2: Popular air source heat pump models in Finland (2025) – comparison of features, price ranges and consumer reviews

Note: Price information and performance values ​​are estimates of typical models based on 2025 data. Consumer ratings are based on a compilation of multiple sources (customer feedback and public ratings). Individual models may differ in their values. All listed models use the environmentally friendly R32 refrigerant and meet at least the requirements of the A++ energy class for heating.

The table shows that the premium brands (Mitsubishi, Daikin, Panasonic, Toshiba, Fujitsu) compete very evenly: they all have high efficiency ratios, versatile features and consumers are mostly very satisfied with the quality. The differences are mainly in the design and some special features (e.g. Daikin's condensation removal innovation or Panasonic's Nanoe X cleaning). The cheaper Gree also offers valid basic functions and even top-class heating capacity in freezing temperatures, but the brand's reputation and long-term experience are still developing. It is important for the consumer to ensure good installation and after-sales service: the big brands offer an extensive network of installers, while for the cheaper ones it is worth using experienced heat pump installers and ensuring the warranty is valid.

To summarize the market in 2025, we can say that competition between manufacturers benefits the consumer : devices have become increasingly efficient, quieter and smarter, while their prices have remained reasonable. Almost all manufacturers have a model that is suitable for the Finnish climate. Therefore, individual needs, such as the size of the space, budget and desired additional features, play a role in the selection. The final chapter of the report provides recommendations for different situations, which will help in choosing a suitable air heat pump.

Summary and recommendations for different needs

Air source heat pumps have proven to be an effective way to improve the energy efficiency and living comfort of buildings. In summary, the following key points about air source heat pumps can be stated:

• An air source heat pump transfers renewable heat energy from the outside air to the interior . This allows heating to be carried out much more cheaply than with direct electricity or oil – savings in heating costs are typically in the range of 20–50%, and the device pays for itself in a few years. At the same time, the device provides cooling in the summer season, which traditional heating methods do not.
  
  

• In terms of operating principle, an air source heat pump is like a refrigerator in reverse: it uses electricity to move heat from one place to another. The technology is mature and reliable, but performance varies depending on the conditions. It is important to choose a model that is designed for northern conditions (frost resistance) and to size it correctly for the space to be heated in order to get the most out of it. Usually, one indoor unit is enough for a spacious floor plan (~50 m² of continuous space), but in maze-like houses or two-story solutions, it is worth considering several units to achieve optimal heat distribution.
  
  

• Operation and maintenance: Daily use of an air source heat pump is simple – the thermostat takes care of the target temperature. It is recommended to keep the pump on continuously during the heating season and let it adjust its output automatically, as constant on/off switching reduces efficiency. However, care should be taken in automatic settings to ensure that the device does not cool unnecessarily in winter (avoid “Auto” mode in winter, use “Heat” instead). The filters should be cleaned (vacuumed/rinsed) about once a month or two, depending on the amount of dust, to maintain good airflow. Leaves, snow and ice should be removed from around the outdoor unit regularly to allow air to circulate unhindered. It is a good idea to have professional maintenance (refrigerant check, deep cleaning) done every ~3–5 years or as needed to keep the device efficient and hygienic. Most modern models indicate the need for maintenance or filter cleaning with flashing signs.
  
  

• Summary of applications: An air source heat pump is ideal for single-family homes where you want to reduce your electric heating costs or reduce oil consumption. Residents of terraced houses and apartment buildings (especially on the upper floors) can also benefit significantly from the cooling function of the ILP. In summer cottages, the pump offers convenient maintenance heat and easy cooling. In garages and workshops, the ILP is often the most cost-effective way to keep the temperature in the positive direction all year round. It is no exaggeration to say that almost every electrically heated building benefits from an air source heat pump – with the possible exception of spaces that are used at a minimum level, where the investment does not have time to pay for itself. If the house already has district heating or geothermal heating, the additional benefit of the ILP is mainly in cooling and air circulation, as the cost savings from district heating would be marginal.
  
  

• Recommendations for different needs:
  
  

• For electric heaters (detached house or large apartment): Purchasing an air source heat pump is highly recommended. Choose an efficient Nordic model with enough heating capacity to cover at least 50% of the house's peak power demand. For example, an ILP with a nominal power of 5 kW is good for a 120 m² house. Benefits: significant savings on electricity bills, return on investment in 3–6 years, increased comfort (more even heat). Keep your old electric heating at least a couple of degrees lower than the setpoint so that the pump does the work first.
  
  

• For oil heater: Suggest adding an ILP alongside an oil boiler to cut oil consumption. The “free” heat produced by the pump significantly reduces the burner’s operating time – experience shows that oil can easily be saved by 30% or more per year. Choose a device with good frost resistance so that it can operate for as long as possible before the boiler starts to fail. The savings are both in euros and emissions; in addition, you get cooling in the summer in the same package. Check for possible subsidies: In Finland, there have been subsidies for replacing oil heating – installing an ILP as supplementary heating may entitle you to some subsidies or at least a household deduction (which can be used against labor costs).
  
  

• Geothermal vs. ILP consideration (new house): If you are building a new house and considering geothermal heating but are on a tight budget, one option is to install direct electric heating + air source heat pump initially. This combination is much cheaper as an investment and can achieve perhaps 50–60% of the savings of geothermal heating. If needed later, geothermal heating can be installed in the future. On the other hand, if the house is quite large and water-circulated underfloor heating is planned, geothermal heating is a long-term solution with a higher yield than ILP. You can also do both: some houses have a ground source heat pump in addition to providing cooling in the summer (with fan coils).
  
  

• For apartment building residents: If your apartment suffers from heat in the summer, consider installing an air-to-air heat pump (“air conditioner”). You need a permit from the housing company, but more and more housing companies are now allowing heat pumps when certain conditions are met (noise level of the outdoor unit, location, condensation water management). Choose a model with a small and quiet outdoor unit. ILP is not very useful for heating if the house is, for example, on district heating – keep it off in winter or only when necessary, for example, to control humidity on the balcony on the coldest days. Note that there are also indoor air circulation cooling devices for apartment buildings that do not have a separate outdoor unit (they blow heat out into the exhaust chimney), but their power and efficiency are lower than ILP.
  
  

• For cottages: Choose an ILP with a maintenance temperature setting of +8 °C or +10 °C for cottage use. In winter, put the pump in maintenance mode, which will keep the cottage dry and at a basic temperature with very low electricity consumption (a few euros per month). Before arriving at the cottage, you can increase the temperature using remote control – many modern models support a smartphone app, or get a separate GSM socket for an older model. In summer, you can cool the cottage if you want, but ventilating it with a draft in the evenings is often enough. Remember to protect the outdoor unit from snow/ice falling from the roof. When placing the outdoor unit in a cottage, it is a good idea to take the snow load into account – preferably install the outdoor unit under the eaves or on a wall bracket high enough so that snow or ice falling from the roof does not damage the device. Also, make sure that the cottage has good basic ventilation, as the ILP itself does not bring in new replacement air.
  
  

In conclusion: An air source heat pump is a profitable investment for many households in the 2020s . It combines energy saving, environmental friendliness and living comfort: one device reduces heating costs, reduces emissions and even acts as air conditioning in the summer heat. Current heat pumps are technically advanced and long-lasting – if used and maintained correctly, the device can operate for 15–20 years , during which time it pays for itself many times over. It is recommended to choose a model from a well-known manufacturer that has good reviews in Finnish conditions, and have the installation done by a certified professional. This way you ensure that you get the full benefit of the air source heat pump. Overall, an air source heat pump represents modern thinking: it utilizes renewable energy in our everyday lives and is a concrete way towards more energy-efficient, comfortable and sustainable living.