Aerothermal Energy




Photo under license CC BY-SA-NC


Aerothermal energy is energy stored in the form of heat in ambient air. This is done through very efficient heat pumps. Heat pumps can produce energy from the heat of the ground, water sources or using air. We can use them for heating, cooling and hot water production, too. It is a low-investment renewable energy source with quick installation.


Based on the type of source, we can differentiate geothermal (ground-source), water source and air source heat pumps. The EU defines aerothermal energy as those regular heat pumps based on air that have an efficiency over 2.5 (meaning that they produce 2.5 times more energy in the building than the electricity consumed).

Air source heat pumps use the ambient energy in outside-air or exhaust-air for heating, cooling and production of hot water. They can be installed as compact units entirely inside or outside the house (so called mono-bloc). Split systems consist of one unit inside the building and one outside of it. Heat is commonly distributed inside the house by a hydronic distribution system or by air using fan coils or a ducted ventilation system.

Aerothermal heat pumps have relatively low investment costs, in addition, the system’s maintenance costs are low but contain the cost of electricity which is needed for the operation.

About 2.5 kW thermal energy is generated per 1 kW of electricity used by the heat pump. It means about 250% efficiency. Conventional gas boilers have around 70-80%, direct electric heating has 35-45% efficiency.


Main Features

  • Compressor
  • Condenser
  • Expansion valve
  • Evaporator

photo under license CC BY-NC-ND

Advantages and challenges

+ Installation can be finalized in days.

+ It is a low-investment renewable energy source.

+ It produces both heat and cooling, making them perfect for Mediterranean regions with hot summers and cold winters.

+ If the country electricity is produced based on a good percentage of renewables it is much cleaner than other conventional technologies.

+ Heat pumps can also be a great solution in case of supermarkets, shopping centres, schools, etc. in urban areas to reduce greenhouse gas emission significantly.


–  Efficiency of heat pumps using sources from air depends on the temperatures of the air, and may vary during the seasons in the year.

–  During summer, these machines expel heat from houses, making it worse in urban areas with heatwaves.

–  Heat pumps need electricity to deliver the produced energy which can cause greenhouse gas emission depending on the electricity’s source.