FAQ

What are the most common questions our consultants get when choosing a FLIXX heat pump or air conditioner?

What types of heat pumps are there?

• Air-to-water
• Air-to-air
• Geothermal (ground-source / soil-to-water)

How heat pumps work

• Air-source heat pumps are the most popular type, extracting heat from outdoor air. They are relatively easy to install and well-suited for temperate climates.
• The operating principle of an air-to-water heat pump is based on redistributing heat rather than generating it. The unit absorbs heat from the ambient air, amplifies it via a compressor, and transfers it to the heating system. Essentially, it works like a “reverse refrigerator.”
• Geothermal systems harness the earth’s natural heat, ensuring high efficiency even at very low outdoor temperatures.

The main differences between a heat pump and an air conditioner.

While an air conditioner is designed solely for cooling a room, a heat pump can operate in both cooling and heating modes.

What is an air conditioner?

An air conditioner is a cooling unit installed in a room to lower the indoor temperature (similar to automotive AC systems). The device takes in room air, cools it down, and recirculates the chilled air back into the space.

What is an Air Source Heat Pump?

An air-source heat pump utilizes thermal energy from the ambient air to provide heating or cooling. Through a built-in evaporator, the heat pump collects this thermal energy, which is then processed by the compressor.

Advantages and disadvantages of heat pumps and air conditioners

Air-to-water heat pump

·  Multifunctionality: heating and cooling in one device.

·  Energy efficiency: especially in heating mode, as the equipment draws heat from natural sources to maintain a comfortable indoor climate.

·  Eco-friendly: Uses environmental resources to generate energy, reducing the load on power grids and reducing the carbon footprint.

·  Durable: With stable maintenance, they last longer than air conditioners or traditional heaters.

Cons of heat pumps:

• High installation cost: The initial investment can be significant.
• Require more space to accommodate the unit: The system needs enough space both inside and outside the building.
• Reduced productivity in freezing temperatures: With a significant drop in temperature, the efficiency of thermal equipment can decrease, although advanced models are equipped with additional features to increase productivity in such conditions.

• Multifunctionality: Provides both heating and cooling in a single device.
• Energy efficiency: Especially high in heating mode, as the equipment draws renewable heat from natural sources to maintain a comfortable indoor climate.
• Eco-friendly: Utilizes environmental energy sources, reducing strain on power grids and lowering your carbon footprint.
• Durability: With regular maintenance, they outlast standard air conditioners or traditional heaters.

Disadvantages:

• High installation cost: The initial investment can be significant.
• Space requirements: The system requires adequate space both inside and outside the building.
• Reduced capacity in freezing temperatures: Efficiency can drop during severe cold snaps, although advanced models feature built-in backup systems to maintain performance.

What is important to know when buying an air-to-water heat pump

Don’t focus solely on power ratings; real-world performance in freezing conditions is what matters most. It is essential to check operating temperature ranges, the availability of auxiliary heaters, and compressor specs.

It is also critical to verify power consumption during peak loads. A low COP (Coefficient of Performance) in sub-zero temperatures can wipe out your energy savings. Equipment certified for cold climates adds an extra layer of reliability.

Common Mistakes:

• Choosing the cheapest models.
• Ignoring the building’s heat loss.
• Failing to perform a proper load calculation.

An uninsulated building will overload even the most powerful heat pump. Therefore, calculations must account for heat loss, regional climate, and the number of floors. There are no one-size-fits-all solutions — only an individual approach.

Monoblock vs. Split Heat Pump: The Main Differences

It is important to understand that both systems differ fundamentally in their design. In a monoblock, everything you need is assembled into a single outdoor unit. In a split system, the components are divided between an outdoor unit and an indoor unit.

Here’s a table to help you compare:

Parameter	Monoblock (All-in-One)	Split System
Layout	Single outdoor enclosure	Indoor and outdoor units
Installation	Simpler	More complex
Risk of Freezing	Present (requires precautions)	Almost none
Indoor Noise	Almost non-existent	Almost non-existent
Pipeline Length	Up to 10–15 meters	Up to 50 meters

A monoblock heat pump is an ideal solution if you want to simplify installation. We often install such models in private houses where indoor space is limited.The main advantage of a monoblock heat pump is its ease of maintenance. It is compact and can be installed both outdoors and in a utility room.

Important consideration: If the water pipes are laid in the open air, they must be carefully insulated, or propylene glycol (antifreeze) must be used in the heating system.

Important consideration: If the water pipes are laid in the open air, they must be carefully insulated, or propylene glycol (antifreeze) must be used in the heating system.

Split system: outdoor and indoor unit

How does it work?

A split system consists of two blocks:

• Outdoor unit is installed outdoors (for example, on a wall, roof or foundation). It contains a compressor that takes heat from the air and transfers it inside.
• Indoor unit is located in the room and connected to the heating system of the house (radiators, underfloor heating or a boiler for hot water).

Both units are connected by pipes through which the refrigerant, a substance that carries heat, circulates.

Advantages of a split system:

Higher efficiency – By keeping the compressor in a warm room, the system loses less heat in winter.
Quiet operation – the compressor (the noisiest part) is installed outside, and there is practically no noise inside the house.
It works better in frost – heat exchange in the room helps to maintain efficiency even at low temperatures.

Disadvantages:

Complex installation – requires a qualified technician to properly install and charge the system with refrigerant.

Risk of refrigerant leakage – if the connection tubes are damaged, the efficiency of the system is reduced.

Monobloc heat pump

How Does a Monobloc Work?

A monobloc is a single device housing all key components in one enclosure. It is installed outdoors, and already-heated water is piped directly into the home’s heating system.

Advantages of FLIXX Monoblock Heat Pumps

• High efficiency and advanced technology. The units maintain excellent performance even at low outdoor temperatures, as the entire product range has been specifically designed for the demanding climate of the Nordic countries.
• Low noise level. The optimized design ensures quiet operation despite the outdoor location of the compressor.
• Easy installation. There is no need to install refrigerant piping between the outdoor and indoor units—only the water pipes need to be connected.
• Minimal risk of refrigerant leaks. The refrigerant circulates exclusively within the sealed outdoor unit, making the system highly reliable and minimizing the risk of leakage.
• Compact design. Since all major components are housed in the outdoor unit, no valuable indoor space is required.

Features (Disadvantages):

• Frost Protection Required: The water pipes connecting the pump and the house must be insulated or protected from freezing (e.g., using special antifreeze valves).

When choosing between a monoblock and a split heat pump, one of the most important factors to consider is the quality of the installation.

For a monobloc, you must insulate the external pipes, especially if the region has cold winters. We always advise using additional electric heating to protect against freezing.

A split system requires a more complex installation, as the refrigerant lines must be installed, evacuated (vacuumed), and carefully checked for leak-tightness. However, refrigerant piping can be routed over long distances, making a split system an excellent choice when the outdoor unit needs to be installed far from the building. We believe that professional installation is the key to long-term reliability and maximum efficiency. Whichever system you choose, installation should always be carried out by qualified professionals to ensure safe, efficient, and trouble-free operation for many years.

Hydraulic Modules for Heat Pumps: Features and Benefits

Hydraulic modules for heat pumps are essential equipment for the optimal operation of heating and domestic hot water systems. They provide a reliable connection between the heat pump and the hydronic system, maintaining stable circulation of the heat transfer fluid and regulating the temperature.

Key Functions of a Hydromodule

Hydraulic modules perform several key functions:

• System Integration: They allow the integration of the heat pump with radiators or underfloor heating systems.
• Heat Transfer Fluid Flow Control: They provide the necessary water pressure and circulation for efficient heating.
• Filtration: They clean the heat transfer fluid from contaminants, prolonging the lifespan of the system.
• Automation: Many models are equipped with temperature and pressure control functions, as well as built-in protection against overheating or freezing.

Water boilers and buffer tanks

What is a buffer tank (Accumulation Tank)? A buffer tank is a steel vessel with hemispherical top and bottom caps. This shape ensures proper pressure distribution and prevents water stagnation. The outer body is hermetically sealed with dense thermal insulation.

Why and when are buffer tanks used? Storage tanks are used in heating systems alongside heat pumps, electric boilers, solid-fuel boilers, and other heat sources. A buffer tank absorbs thermal fluctuations, protects the system from overheating (boiling), and maintains coolant temperature for a period of time even after the heat source is turned off.

·  What is an indirect heating tank (Water Tank / Boiler)? An indirect heating tank is integrated into the domestic water supply system like a standard storage water heater. It features one or two internal heat exchangers connected to a heat pump, solid-fuel boiler, electric/gas boiler, or solar collectors.

Summary (Differences between a buffer tank and an indirect water heater):

• A buffer tank stores thermal energy for the heating system.
• An indirect heating tank prepares domestic hot water (DHW) for showers and taps by utilizing heat from an external source (like a heat pump).

·  Combined buffer tank: A hybrid thermal accumulator that combines the functions of both a buffer tank and a DHW water heater, providing space heating and domestic hot water simultaneously.

·  What is a heat pump water heater? A heat pump water heater is an innovative water-heating solution operating on heat-pump principles. It is designed to supply hot water to residential and commercial properties lacking access to centralized hot water systems.

In addition to heating water up to 75°C, it can also heat small areas (e.g., via underfloor heating). Available in capacities from 150 to 300 liters to suit almost any requirement.

Operating Principle: The system utilizes ambient environmental heat. It consists of two circuits: an external circuit that collects heat from outside air and an internal circuit where a heat exchanger transfers that warmth directly to the water.

WHAT IS A HEAT PUMP BOILER ?

A heat pump boiler is an innovative water heating solution that uses the heat pump principle. It is designed to provide hot water to residential and commercial facilities where it is not possible to connect to centralized hot water supply.

It not only heats water up to 75 degrees, but can also be used to heat small rooms, for example, through an underfloor heating system.

The variability of tanks from 150 to 300 liters allows you to choose for almost any need.

The principle of operation of a heat pump boiler is based on the use of the heat of the environment to heat water. The device consists of two circuits: external and internal. The outer circuit collects heat from the environment, in this case from the air, and transfers it to the inner circuit. The internal circuit contains a heat exchanger in which heat is transferred from the external circuit to the water.

About ventilation

Ventilation is the process of indoor air exchange that removes stale air and brings in fresh air. Without proper ventilation, moisture, odors, and carbon dioxide build up, leading to stuffiness, humidity, and mold growth.

What types of ventilation are there? Natural and forced.

Forced ventilation includes: supply ventilation, exhaust ventilation, and supply-and-exhaust ventilation.

• Natural ventilation: Air exchange that occurs without fans or electrical devices. Air moves naturally due to pressure differences (indoor vs. outdoor temperature) and wind pressure.
• Supply ventilation: A mechanical system that supplies fresh air to a room. A special fan draws air from the outside and delivers it inside via air ducts or wall vents. Before entering rooms, the air usually passes through dust filters and can be heated during the cold season.
  • Pros: Stable fresh air supply; climate control options; suitable for airtight spaces.
  • Cons: Requires electricity, regular maintenance, and proper engineering design.
• Exhaust ventilation: A system designed to forcibly remove stale air from a room. Fans extract humid, polluted, or stuffy air through exhaust grilles and ducts (e.g., in kitchens or bathrooms) and vent it outside. This creates a slight negative pressure, drawing fresh air in through windows or special inlets.
  • Pros: Removes moisture and odors; prevents fungus and mold; compact design.
  • Cons: Can create drafts and cool down the room if makeup air isn’t tempered.
• Supply-and-exhaust ventilation: Combines both processes: simultaneously supplying fresh air and extracting stale air. Typically, this is a centralized system with two fans or a single unit that channels fresh air into living areas while extracting it from humid or polluted zones (kitchens, bathrooms). Modern units feature a heat exchanger (recuperator) that transfers heat from outgoing air to incoming air, ensuring minimal heat loss. Cons include higher equipment costs, complex installation, and required maintenance.

How to choose a ventilation system? Consider the following factors:

Pollution sources: Kitchen appliances, office equipment, etc.

Room area: The larger the space, the higher the required air exchange rate.

Purpose: Kitchen, bathroom, living room, office, or warehouse.

Air tightness: Presence of modern plastic windows, insulation level.

Climate: Local outdoor temperature and humidity levels.