Comparison Bosch Compress 7000i AW 9E 9 kW vs Mitsubishi Electric PUHZ-SW100VHA 11 kW

— Indoor unit (hydromodule). The part of a heat pump that is installed indoors. By definition, it is included in the delivery set of "ground-water" units (see "Heat source") — the indoor unit, in this case, is the actual heat pump, only the collector and connecting pipes are brought out. But air models may not have this module.

— Outdoor unit. It is not used in ground-to-water models. However, it is an almost obligatory element of a complete set for air-to-water units. Usually, the outdoor unit also includes a collector for heat extraction. However, there are air heat pumps that can be installed indoors, with air supply and exhaust through ventilation ducts. — however, for such models, only the indoor unit is indicated in the package, although the device can usually be installed outdoors. And there are even monoblock models that combine an indoor and outdoor unit in one case.

— Water heater. A device for heating water and supplying it to the DHW system; see "Water heater" for details. The presence of a built-in water heater, on the one hand, simplifies the installation of the pump and eliminates the need to purchase additional equipment; on the other hand, when buying such a pump, you have to rely on the choice of the manufacturer, while an external water heater can be purchased separately.

The maximum heat output generated by a heat pump is the amount of heat it can transfer from the outdoors into the heating system and/or domestic hot water.

The heat output is the most important spec of a heat pump. It directly determines its efficiency and ability to provide the required amount of heat. Note that this spec is shown for optimal operating conditions. Such conditions are rare, so the actual output heat is usually noticeably lower than the maximum; this must be taken into account when choosing. There are special formulas for calculating the optimal value of the maximum heat output, depending on the specific condition.

Heat output is the amount of heat generated by a heat pump at a source temperature (air or ground - see above) of about 0 °C. This indicator is more visual and closer to reality than the maximum heat output (see above), so it is often indicated in the characteristics as the main one.

The required heat output depends on the area and some features of the room, on the need for hot water and a number of other factors; for its calculation in special sources, you can find the appropriate formulas.

Maximum cooling output delivered by the pump.

The pump operates in the cooling mode removing excess heat from the room to the environment — it plays the role of an air conditioner. The required cooling capacity depends on the area of the building, the specs of its thermal insulation and some other factors; methods of its calculation can be found in special sources. Also note here that conventional heating equipment (radiators, underfloor heating) is not suitable for cooling, for this it is necessary to use special equipment (for example, fan coil units).

Electric power consumed by the heat pump when operating only for heat transfer, without the use of an additional heating element (if any, see below). The ratio of thermal power to power input determines the thermal coefficient COP (see below) and, accordingly, the overall efficiency of the unit. It also affects overall power consumption (and therefore electricity bills), as well as some power and connection requirements — for example, models powered by 230 V and with a power of more than 5 kW cannot work from an outlet and require a special connection to the mains.

Type of power supply used by the heat pump.

- Single-phase (230 V). Many models with such a power supply can operate from a conventional outlet, which makes it much easier to connect. However, high power consumption (3.5 kW and above) requires connection to the mains via a distribution board .

- Three-phase (400 V). Power supply from 400 V mains is suitable for heat pumps of any power, including for models equipped with high-consumption heating elements. In addition, devices with such a supply during continuous operation consume less energy than single-phase devices of similar power consumption. Thus, this option can be envisaged even in heat pumps of low power. The disadvantage of three-phase mains is the necessity to ask for the help of a professional electrician to connect the unit.

The power of the heating element installed in the device (if such a function is available).

It isan electric heater in the form of a tube with an incandescent filament inside. Such a heater plays an auxiliary role; it is used when the heat output of the pump itself is not enough — for example, with a significant drop in temperature outside. The main advantage of heating elements is that their efficiency does not depend on outdoor conditions. And the main disadvantage is the high energy consumption. If the heat pump can transfer much more heat energy than it consumes electricity, then the heat output of the heating element is approximately equal to the consumed one. That is why the specs indicate the power of the heating element in general, without specifying what it is about: the indicated figure corresponds to both the heating power and energy consumption. These parameters are similar to those of the heat pump itself; see above for more details.

The highest temperature to which the pump can heat the coolant. It is worth noting that such indicators can be achieved at a fairly high temperature of air or ground. And since heat pumps are used during the cold season, the actual maximum temperature, usually, is less than theoretically achievable. Nevertheless, this parameter makes it possible to evaluate the capabilities of the unit or its suitability for certain tasks.

The COP (coefficient of performance) is a key characteristic that describes the overall efficiency of a heat pump. It represents the ratio between the thermal power and power consumption of the unit (see above) – in other words, how many kilowatts of thermal energy the pump produces per 1 kW of electricity consumed. In modern heat pumps, this figure can exceed 5.

However, note that the actual COP value may vary depending on the outside temperature and the supply temperature. The higher the difference between these temperatures, the more resources are needed to “pump” thermal energy and the lower the COP will be. Therefore, in the specifications it is customary to indicate the COP value for specific temperatures (and in many models – two values, for different options) – this allows you to evaluate the actual capabilities of the unit.