Heat Pump Electricity Consumption
In addition to the working principle of heat pumps, one of the most frequently asked questions is about their electricity consumption. In this section, we will explore the electricity consumption of heat pumps and the factors that influence it.
Heat pumps draw their energy from nature, providing heating and cooling needs for the area where they are installed. They take 70% of their energy from nature, while 30% comes from the users' electricity bills. The electricity consumption of a heat pump depends on multiple factors, not just a single reason. Let's examine these factors in detail.
- Compressor Consumption
The main factor that contributes to electricity consumption is the compressor's energy use. Heat pumps, which are renewable energy systems, have mechanical components such as compressors, four-way valves, and expansion valves. For a heat pump to function, these components must complete the circulation process. In order for the compressor to operate and the system to start, the electrical current must reach the compressor. The power drawn by the compressor determines the electricity consumption, and the compressor's hourly power usage is measured in kilowatts (kW).
The type, brand, and size of the compressor affect the energy it draws, either increasing or decreasing the consumption. Basic compressors provide energy based on their efficiency, regardless of the energy needs of the space being conditioned. They tend to use more electricity as they cycle on and off in response to temperature fluctuations.
However, DC inverter compressors adjust their output to the energy needs of the conditioned space, gradually decreasing their power usage once the desired temperature is reached, which makes them more energy-efficient than basic compressors.
- Type of Heat Pump
Heat pumps draw part of their energy from natural sources such as air, water, and soil. Due to the nature of these sources, heat pumps that use water and soil (geothermal) consume less electricity than those that use air.
Air-source heat pumps do not have a fixed electricity consumption. When the outdoor temperature is low, these systems must work harder, consuming more electricity. Additionally, the fans inside air-source heat pumps consume a small amount of electricity, further increasing overall consumption.
Water-source heat pumps draw energy from underground water sources that do not freeze, meaning the water temperature remains more stable than outdoor air temperatures. As a result, water-source heat pumps consume less electricity than air-source heat pumps.
The most efficient type of heat pump is the ground-source (geothermal) heat pump. Regardless of temperature changes, the temperature of the soil underground remains nearly constant, making geothermal heat pumps the most energy-efficient, consuming the least amount of electricity.
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Building's Heating System
Heat pumps transfer heat through various heating systems inside the building, such as underfloor heating, radiators, fan coils, and wall heating. The type of system used in the building has a direct impact on electricity consumption. In a traditional radiator system, the inlet temperature is between 50–60°C, whereas underfloor heating operates at a temperature range of 10–35°C. Therefore, more electricity is used to reach the higher temperature of radiators than to achieve the lower temperatures needed for underfloor heating. Underfloor heating helps reduce electricity consumption when using a heat pump. -
Insulation
Insulation is important not only for heat pumps but also for saving energy in general, even with fossil fuels. Depending on the building’s condition, insulation can save between 20% and 70% of heat energy. This means fuel and cost savings as well.
In the case of a building without insulation, a heat pump with a higher kW rating will be chosen during the calculation phase, while for a well-insulated building, a lower kW heat pump will be selected. Thus, larger heat pumps will consume more electricity.
- Location of the Space to be Climatised
Another important factor when determining the required energy for a heat pump is the location of the space to be conditioned. For example, the heat pump chosen for two houses with the same square footage in the Eastern Anatolia and Aegean regions will differ. In colder regions, heat pumps provide higher efficiency, but they also consume more electricity due to the harsher climate conditions.
