BarcelonaWith the rise in the price of electricity and gas, the cost of turning on the heating or, when summer arrives, the air conditioning multiplies. So it’s a good time to look for alternative systems to heat your home (and also your water) and make them cleaner. Two good examples are the geothermal and aerothermal systems, which are becoming more frequent and which, despite having a high initial cost, are very efficient and in the long run can save money.
Geothermal and aerothermal are very different from each other, but they have in common that they are clean systems, because they save more carbon dioxide emissions than they spend on operation. The facilities and especially the energy source are the elements that differentiate them: geothermal energy gets the energy from the subsoil and aerothermal energy from the heat of the air in the environment.
Geothermal energy consists of a heat pump located underground. The temperature below ground is about 15 degrees, so the pump takes the heat from the basement and sends it home when it needs to be heated, while doing the opposite system – the heat from the home is ‘injects into the basement – when the temperature of the house should be lowered in the summer. This pump, which is usually placed in a closed room, represents the highest cost, usually 10,000 euros or more: depending on the square meters of the house, the pump will be more or less powerful and therefore more or less expensive.
Drilling the ground is the other big cost. The system that captures heat is a tube with a liquid, usually water (sometimes antifreeze) that moves through a circuit thanks to the pump and is heated and cooled. The price is about 30 or 35 euros per meter drilled, although depending on the type of soil it can go up to 40 euros if you have a vertical capture system, the most common and which consists of making a much larger hole. deep, about 200 meters. The horizontal capture system is cheaper, between 20 and 25 euros per meter, but requires much more surface than it has to heat: if the house is 100 square meters, the installation needs about 150 or 200 .
The other part of the cost of geothermal energy is the installation to distribute heat throughout the home, often with underfloor heating, as well as other components of the installation such as the water accumulator and the appliance. which allows the circuit to be reversed for use in heating or cooling. In total, an installation can cost between 15,000 and 30,000 euros, depending on the size of the house, the type of pump and the floor. This means that it takes years to pay off, but the savings in electricity or gas consumption are 80%, which also has a very positive environmental impact.
On the other hand, in the case of aerothermal energy, the cost of the installation is lower, usually between 8,000 and 25,000 euros. Again, the pump is one of the most expensive parts, with a price starting at 1,500 euros, although it can reach 12,000 euros.
The air heat pump absorbs heat from the environment, even when it is cold outside – the absolute absence of heat occurs at -273 degrees, a temperature that never occurs on planet Earth – so there is a remarkable saving because it is not necessary to drill the ground. Now, the performance is not constant, because it will not work the same if the air in the environment is at 10 degrees than if it is at 10 below zero.
Public subsidies
The ideal system for transmitting heat at home is underfloor heating, although it also works well with other methods, such as low temperature radiators and fan coil units (common air radiators in offices or shops). If you take advantage of the traditional radiator installation used with gas or diesel boilers, the yield is 40% lower, but it works the same.
Despite the high cost of installing these two systems, it should be borne in mind that public administrations often provide aid, in the context of policy to encourage the ecological transition. In the case of aerothermal energy, until 31 December next year there will be a grant from the Spanish government of a maximum of 3,000 euros per home.