Heating a home with aerothermal energy -air conditioning units- is 25% cheaper than doing it with a natural gas boiler, and practically half if the comparison is made with a diesel boiler, according to Toshiba studies. In addition, according to the regulations, renewable energy would be generated.
Air conditioning devices are heat pumps, which transfer energy from a cold source to a hot one or vice versa, that is, they convert the thermal energy of the environment into useful heat. This environment can be the atmosphere, and we speak of aerothermal energy, the subsoil -geothermal energy- or water, referring to hydrothermal energy.
The usual thing is that heat pumps, when working, offer more energy than they receive. On a commercial scale, air conditioning units provide three or four thermal kWh for each electrical kWh of input to exchange energy with the environment. In the laboratory, this performance becomes one to 10, that is, for each electrical kWh they produce 10 thermal kWh.
Toshiba, one of the main manufacturers of air conditioners, with the intention of promoting its products, has compared the cost that a real home incurs to heat itself if it uses aerothermal energy or if it uses conventional boilers, both natural gas and Diesel C, and the results are extraordinarily favorable the first time.
A big house in Vizcaya
The Japanese manufacturer has chosen a 180-square-meter single-family home in Zalla (Vizcaya), a cold area of the country. The cost of heating that this home needs to cover its annual needs -estimated at 20,000 thermal kWh- varies from 687 euros in the case of aerothermal energy, to 937 euros in the case of a natural gas boiler, and 1,293 euros. for a new C diesel boiler and 1,572 euros for an old boiler. In other words, in the worst case, aerothermal energy manages to produce the 20,000 thermal kWh required 25 percent cheaper than the next option.
The explanation for this lower cost lies in the lower need for energy from the machines. Air conditioning -with a performance of 300 percent- only requires 6,667 electric kWh to generate the 20,000 thermal kWh, while the other two technologies require more energy: 20,747 kWh in the case of natural gas and 21,930 kWh in the case of the boiler new diesel C.
In addition, according to the legislation, each kWh that the heat pump manages to capture from the environment and convert into useful heat is considered renewable. Of course, only if it is used for heating, not for cooling, because the countries of southern Europe -and Spain in particular- rejected that option when the European Clean Energy Directive was being negotiated.
Returning to the case at hand, the electricity rate considered is the Conect@Luz de Iberdrola with hourly discrimination, while in the other two the regulated rate (TUR) for gas and diesel for heating have been considered.
Of course, the home had to increase the contracted electrical power from 3.1 kW to 4.4 kW to obtain the desired amount of heating.
Individual counters down another 25%
The installation of heating cost allocators and thermostatic valves saves an average of 24.7 percent in heating consumption in homes in buildings with central heating, according to a study by the University of Alcalá for the Spanish Association of Cost Allocators heating. The average energy savings of the 1,349 homes analyzed correspond to about 7 GWh, equivalent to eight months of electricity consumption in a typical home.
The report confirms that among the measures aimed at saving energy in central heating installations, the use of cost allocators and thermostatic valves is the most efficient. And that this type of measure also avoids an average of 61 tons of CO2 per year.
According to a European Directive, mandatory for member countries and which Spain should have already transposed, a total of 1.7 million homes with a centralized heating system should have installed water and heating meters.
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