Aerothermal energy seeks its place in homes

The name aerothermal energy is heard more and more. These devices, which run on electricity and are available in any specialized store or chain, are state-of-the-art heat pumps designed to provide heating in winter, cooling in summer and hot water all year round. The technology, which works by extracting the environmental energy contained in the air through a thermodynamic cycle, is postulated as the most efficient alternative for heating and cooling homes in the not too distant future, to perform, thanks to its performance (400% higher than any other thermal equipment), a key role in the decarbonization of the real estate stock.

During 2022, a total of 70,300 units of multitasking heat pumps (aerothermal plus geothermal) were sold, which represents an increase of 48% compared to the previous year. While the marketing of heat pumps only for domestic hot water reached 25,000 units (51.5% more), according to the Association of Manufacturers of Heat Generators and Emitters (Fegeca).

Sales are growing, but Spain remains the fifth European country with the lowest rate of equipment sold. Although they are between three and five times more efficient than their fossil competitors, these devices are still far behind the share represented by gas boilers, present in 40% of homes. The price and size of these devices, as well as their viability are some of the questions regarding aerothermal energy. In new construction it is easy to design a building taking into account renewable solutions like this, but in existing buildings it is more complicated to overcome the technical impossibility, especially in old buildings where the installation of heat pumps is prevented due to space problems and it is prohibited to place equipment on the facades. “In new construction, the option most chosen for the production of domestic hot water and air conditioning is aerothermal energy. The situation changes in rehabilitation, when we have reduced spaces inside or we cannot have the façade or the roof for the placement of the outdoor units,” explains Sonia Pomar, general director of Fegeca. “Noise regulations or the needs for air supplied by the outdoor unit make it more complicated to replace old gas boilers with heat pumps in block residential buildings,” she adds.

Floor characteristics

Inmaculada Peiró, general director of Agremia, the Association of Companies in the Facilities and Energy Sector, also points to the technical characteristics of the property in which the equipment is to be installed: for a 70 square meter apartment, in a city, and with a five-meter kitchen (it is estimated that 70% of the population lives like this), “it is complex to replace a boiler with an aerothermal heat pump, mainly due to the space occupied by the domestic hot water tank because it is similar to the size of a refrigerator.”

At this point, from the Renovables Foundation, its head of Communication and Climate Policy, Ismael Morales, proposes the creation of a heating electrification plan for 2025-2030, replacing fossil fuel systems with heat pumps. “One of the lines of action may be to maintain the heat distribution system, to minimize the carrying out of works, and that includes the mandatory replacement of all boilers that are more than 10 years old or that are not condensing,” he proposes. he. If this action is carried out, we could reach a significant park of installed gas boilers because there are currently nine million units in Spain. “Of these, it is estimated that 65% are of considerable age and have a lower level of efficiency than the equipment currently on the market,” says Peiró.

There is a “but”: at the moment, aerothermal equipment is much more expensive than a condensing boiler, so it is not available to all citizens. The cost of aerothermal heat pumps ranges between 3,600 and 12,700 euros, according to the OCU, to which must be added the installation cost set between 2,000 and 8,000 euros, plus VAT. However, the cost of a wall-mounted condensing gas boiler “would be around 1,500 and 2,000 euros plus VAT,” calculates Pomar.

However, if the long-term investment is taken into account, the outlay pays off. Francisco Zuloaga, Ecodes consultant and expert in renewable heating, believes “if we consider the operating costs, the evolution of gas and electricity prices, the price of housing, and the costs of the heat pump itself, “This appears to be the most advantageous option,” states the publication Cazamitos del Hidrogen of this organization. “There are also numerous subsidies for the aerothermal heat pump and almost no administration now subsidizes gas boilers. In fact, the agreement on the Energy Efficiency of Buildings Directive decrees the end of aid for this type of boilers as of January 1, 2025″, he justifies.

The study The condensing boiler, an opportunity for the decarbonization of homes without limitations, by the Spanish Gas Association (Sedigas), establishes that the replacement of the entire inefficient park of gas boilers with aerothermal equipment would mean a cost of 201,314 million euros, the equivalent of nearly twice the public spending on national health and 15 times more than the replacement of high-efficiency gas boilers.

However, Laureano Matas, secretary of the Superior Council of the Colleges of Architects of Spain (CSCAE), considers that intervening only in the facilities, replacing boilers with heat pumps, without first acting on the envelope of the building to reduce its energy demand, Not only will it not ensure compliance with European requirements, “but the obsolescence that this equipment incorporates will, one day, return us to square one, and that is what we must avoid, optimizing resources.”

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