How to choose a heat pump: what parameters should be considered when choosing

Published 16 Jul 2022
Updated 03 Jul 2023
16 мин чтения
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  1. Main types of heat pumps
    1. Air-to-air heat pumps
    2. Air-to-water heat pumps
    3. System type “water-to-water”
    4. Heat pump “ground-to-water”
  2. Factors that affect the choice of a heat pump
    1. Purpose of the system
    2. Place of installation
    3. Required heat pump power
    4. Heating system
    5. Budget for the purchase and installation of equipment
  3. Equipment parameters
    1. Heat source
    2. Energy consumption
    3. Coefficient of performance
    4. Compressor type
    5. Configuration and equipment
    6. Operating modes
    7. Heat carrier temperature
    8. Noise level
    9. Refrigerant type
    10. System size
  4. Which heat pump is better to choose in ukraine
    1. How to choose the right heat pump?
    2. When the installation of a heat pump is not justified
  5. FAQ
    1. How to choose a heat pump for home?
    2. Which heat pump brand to choose?
    3. How to calculate the final cost of the heat pump?
  6. Video reviews
Heat pump
Heat pump

In the modern world, effective engineering systems are rapidly gaining popularity. This is due not only to extensive functionality, but also to a high level of energy efficiency. One such system is a heat pump.

The energy efficiency of a heat pump is characterized by two indicators:

  1. COP - heat performance coefficient;
  2. EER - energy efficiency ratio.

The higher these indicators, the more efficient the system.

In this article, you will learn what these indicators affect, the capabilities of different types of heat pumps, and much more.

Main types of heat pumps

Air-to-air heat pumps

The air-to-air heat pump looks like a classic air conditioner; it also has one indoor and one outdoor unit. A copper line through which the refrigerant moves interconnect these units. The main function of the outdoor unit in heating mode is to heat the Freon (refrigerant) using the low-grade heat of the outdoor air. In summer, the outdoor unit cools the Freon.

The internal unit is intended for cooling/heating of air indoors.

Air-to-air heat pump
Air-to-air heat pump

Different types of devices can be used as an indoor unit:

  • floor;
  • wall;
  • ducted;
  • cassette.

The air-to-air heat pump is mainly used for southern countries.

This unit is not recommended to be used as the main device for heating, since Ukraine is characterized by low temperatures during the heating season, and the air-to-air heat pump loses its efficiency.

Air-to-water heat pumps

Air-to-water heat pumps
Air-to-water heat pumps

Air-to-water heat pumps heat pump is a versatile system that can simultaneously perform 3 tasks:

  • DHW (hot water supply);
  • heating;
  • cooling.

In addition, the unit is energy efficient equipment, since it uses an inexhaustible source of energy - air.

This type of heat pump uses the energy of air to heat the heat carrier in the system, which is water. Further, the heat carrier is transported to the following elements:

  • Underfloor heating system.
  • Fan coil units (used for heating in winter and for cooling in summer).
  • In-floor convectors (for both heating and cooling) are used in case of having panoramic windows.
  • Tank for hot water supply.

An air-to-water heat pump is a device that, with proper design and installation, creates comfortable conditions for a person throughout the year. We will talk in more detail about how to choose a heat pump and what aspects to pay attention to in the following sections.

System type “water-to-water”

The water-to-water heat pump

uses groundwater as an energy source. A mandatory factor for the implementation of this solution is the presence of a reservoir near the house. During installation, wells are drilled to take away the low-grade heat of groundwater. It is worth noting that in order to carry out this type of work, it is necessary to obtain permission from special services. In addition, the efficiency and durability of the system will depend on the quality of groundwater. The heat pump of this type, as well as the previous version, can implement 3 functions:

  1. DHW (hot water supply);
  2. heating;
  3. cooling.

Heat pump “ground-to-water”

Heat pump
Heat pump "ground-to-water"

A ground-to-water heat pump

is equipment that can perform the functions of water heating, heating and cooling. In this case, low-potential energy of the earth is used. Since the ground temperature is practically unchanged (on average +12°C), the device stably maintains a comfortable microclimate in the house.

The geothermal heat pump is used for houses larger than 200 m2.

The implementation of this heating system is more expensive in comparison with an air heat pump, since additional earthworks are required (drilling wells, immersing the probe, etc.).

Factors that affect the choice of a heat pump

Purpose of the system

Heat pumps are universal devices for creating an energy-efficient and efficient engineering system. Thus, all heat pumps (except air-to-air) perform the following range of functions:

  • DHW (hot water supply);
  • cooling in summer;
  • heating in winter.

Place of installation

The main components of the system are installed in the boiler room: boiler, buffer tank, hot water tank, pump groups, heat distribution manifolds, automation, etc

Boiler house schematic
Boiler house schematic

Required heat pump power

We have repeatedly mentioned that a heat pump is an energy efficient equipment. However, before choosing a heat pump, it is necessary to discuss the basic requirements for high-quality implementation.

  1. External housing structures must have low thermal conductivity, that is, be well-insulated. Thus, heat will not flow outside.
  2. High-quality double-glazed windows. It is important that the windows do not let the cold in.
  3. The presence of supply and exhaust ventilation with heat recovery. Usually people ventilate the room with windows, but in this way heat is released outside. As a result, the cold from the street gets into the room, which entails not only discomfort, but also an additional load on the heating system is created, which means additional financial expenses. Supply and exhaust ventilation with recuperation allows you to heat the supply of fresh air due to the heat of the exhaust air that is removed. As a result, energy costs for heating the air are reduced and the level of comfort for residents is increased.
  4. The heat pump works effectively at low-temperature mode of the heat carrier (up to 45 ° C), so a prerequisite is the presence of underfloor heating that will cover the entire area of the housing.
  5. Implementation of all functions of the heat pump (DHW, heating and cooling).

For heating, a system of underfloor heating and additional heating devices are used. We know that when using a heat pump, the heating system operates in low temperature mode. At the same time, the floor temperature is from + 24°C to + 26°C. However, in the case of frost, with a low-temperature regime of the system, a warm floor can be ineffective. Yes, there is an option to raise the temperature (not higher than 45 ° C) of the heat carrier, however, the floor surface will become too hot and there will be noticeable discomfort for the human foot.

The underfloor heating itself is ineffective, so Alter Air experts recommend installing additional units:

  • Fan coil unit is the best option because it works both for cooling and heating the room, and it is important for us to implement the full potential of the heat pump.
  • In-floor convector, also capable of two functions, but much more expensive than a fan coil unit.
  • Radiator - heating device.

If your house complies with energy efficiency standards, you can proceed to a thermal calculation, which involves an analysis of the characteristics of the building structure (materials used, thermal conductivity coefficient, level of solar control of a double-glazed window (G-factor)).

As a result, we will find out the amount of heat loss in the building, and we can proceed to the next stage – the selection of the power of the heat pump.

Heating system

In order to install a heat pump, it is necessary to consider what kind of heating system exists at the moment.

In any case, there are two options:

  1. this is a new house that does not yet have a heating system;
  2. it is an old house with an existing heating system.

If this is a new house, then it is possible to install a heat pump, but you need to consider:

  • area of ​​the building (the larger the area, the less likely it is that the air-to-water heat pump can cover the needs of heating, cooling, hot water. Then, it makes sense to consider a geothermal heat pump),
  • energy efficiency of the house (its heat loss),
  • availability of financial investments.

After all engineering calculations, the type of heat pump and the necessary elements of the system are selected.

If currently there is no financial opportunity to install a turnkey heat pump, Alter Air offers a combined heating option for the first time. In this case, at the construction stage, it is necessary to provide for the possible installation of this system in the future – to provide the necessary thermal insulation of structures, low-temperature mode, install underfloor heating. As a temporary source of heat, you can use either a gas or electric boiler, and later switch to a heat pump.

If this is an old house with a heating system, the question arises, how to switch from an existing system to a heat pump?

In most cases, switching to a heat pump is impossible, or rather unreasonable, since the COP will be low. For example, if a gas boiler is installed, this means that there are radiators that are designed for high temperatures (up to + 80 ° C). Also, with an electric boiler: if the system is designed only for radiators, the COP of the thermal boiler will be low. Yes, when installing a heat pump, operating costs will decrease, but the level of energy efficiency will be insufficient. Thus, instead of a possible COP of 3.5, it will only be 1.8. The payback of such a system will be very long.

Therefore, if the existing heating system is not designed for low-temperature conditions, there is no underfloor heating system, then the installation of a heat pump will not be effective.

Budget for the purchase and installation of equipment

Heat pump
Heat pump

The cost of implementing an engineering system depends on the area of ​​the building and the equipment used, so it is quite difficult to determine the average budget.

If we consider the implementation of a boiler room for a 10 kW air-to-water heat pump, this is 8000-12000 €. It is worth noting that this price does not include fan coil units, underfloor heating system, etc.

The installation of a geothermal pump will cost 6,000 € more, since wells must be installed to extract heat from the ground.

On average, the payback period for an air-to-water heat pump is 7-8 years compared to a geothermal one.

Geothermal – up to 10 years compared to a gas or electric boiler.

Equipment parameters

Heat source

Heat sources differ depending on the type of a heat pump.

For example:

  • Air source heat pumps of the air-to-air and air-to-water types use air energy.
  • The heat source of a ground-to-water heat pump is the ground.
  • The water-to-water heat pump uses the energy of water.

Energy consumption

Before choosing a heat pump, you need to find out how much electricity it consumes and how much heat energy the device produces.

The amount of energy consumed directly depends on the energy efficiency of the house.

Coefficient of performance

The main indicator of energy efficiency in heating mode is COP - heat performance coefficient. The COP depends on the quality of project implementation. For a high COP, it is necessary to fulfill the conditions that we considered earlier, namely the presence of:

  • thermal insulation and high-quality double-glazed windows;
  • supply and exhaust ventilation with recuperation;
  • low-temperature mode of the heating system using underfloor heating and fan coil units.

Air-to-water heat pumps, consuming 1 kW of energy, are able to produce 3 kW of thermal energy (COP=3), and geothermal pumps 5 kW (COP=5).

To characterize the efficiency of the heat pump in cooling mode, EER is used - energy efficiency ratio.

The VAILLANT air-to-water heat pump with a capacity of 10 kW is characterized by:

COP - 2.8, EER - 2.6.

The ground-water heat pump VAILLANT with a capacity of 10 kW is characterized by:

COP - 5, EER - 4.8.

Compressor type

The difference between inverter and non-inverter compressor
The difference between inverter and non-inverter compressor

Mainly inverter compressor is used.

Principle of operation:

When first turned on, the device operates at full power to achieve the required parameters indoors. Further, the compressor speed decreases, but the heat pump does not turn off. With fluctuations in temperature, the unit independently regulates the power, increasing or decreasing it.

Configuration and equipment

Configuration and equipment
Configuration and equipment

The main elements of the heat pump:

  • Outdoor unit. When using a geothermal heat pump, wells are used.
  • Indoor unit.
  • Underfloor heating system.
  • Fan coil units.
  • DHW tank.
  • Expansion tank.
  • Pump groups.
  • Automation and other groups

Operating modes

The heat pump has 3 modes of operation:

  • heating;
  • cooling;
  • DHW (hot water supply).

Heat carrier temperature

The heat pump requires low-temperature operation (up to +45°C), and the temperature of the underfloor heating should be 24-26°C.

Noise level

For an air-to-water heat pump, the noise may come from an outdoor unit that is located outdoors. High noise levels are typical for winter, when the device operates at high power. Thus, 59 dB is the maximum criterion for noise.

Geothermal heat pumps do not make noise, since the outdoor unit is underground, most of the system is hidden underground.


Refrigerant type

The following types of refrigerant can be used:

  • R-410A.
  • R-32.

R-410A is a refrigerant that does not harm the environment.

R-32 is a more advanced type of refrigerant that is also safe for the Earth's ozone layer.

System size

The size of the system is considered during placement and installation. Depending on the dimensions of the equipment, the most convenient location is selected.

Which heat pump is better to choose in ukraine

Air-to-water and ground-to-water heat pumps are best suited for the climate of Ukraine.

The air heat pump is selected for an area up to 200 m2 (suitable for an apartment and for a house).

The geothermal heat pump is used only for houses with an area of ​​​​200 m2.

How to choose the right heat pump?

The efficiency of air-to-water heat pumps depends on the air temperature, which is not stable throughout the year. This type of heat pump operates efficiently until the air temperature drops below -7°C.

Ukraine is characterized by cold winters, so for high-quality and stable temperature maintenance, it is necessary to install an additional heat source. It can be an electric or gas boiler.

Geothermal pumps in most cases independently provide comfortable conditions for people. Since the temperature of the earth is stable throughout the year (+12 °C), these devices can operate up to -22 °C.

When the installation of a heat pump is not justified

Heat pump
Heat pump

Installing a heat pump is not justified if the house or apartment does not have:

  1. thermal insulation and high-quality double-glazed windows;
  2. supply and exhaust ventilation;
  3. underfloor heating;
  4. fan coils.


How to choose a heat pump for home?

Before choosing a heat pump, it is necessary to analyze the technical characteristics of the housing, then calculate the heat loss, and only then proceed to the selection of equipment.

Which heat pump brand to choose?

Our customers often ask themselves the question: which heat pump is better to choose? Alter Air experts recommend considering trusted brands with which we have been cooperating for a long time:

  • Vaillant;
  • Viessmann;
  • Olimpia Splendid;
  • Cooper&Hunter.

How to calculate the final cost of the heat pump?

The final cost of the heat pump includes:

  • design and selection of equipment;
  • installation of the system;
  • all the necessary components for the engineering system (underfloor heating, fan coil units, automation, buffer tank, hot water tank, etc.).

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