The air conditioning

The number of citizens who purchase an air conditioner is increasing. Very few homes are built with centralized air conditioning, this is a serious mistake, especially in very hot areas like Andalusia. Centralized air conditioning is much more energy efficient than the so-called "splits" also avoid having to place the devices on the facades of buildings.

In summer it is enough to be at 25 ºC inside the home. It is not recommended to have a difference of more than 12ºC with respect to the outside temperature.


Nearly 50% of the energy consumed in the home is used to heat the houses. Its use, obviously, depends a lot on the climate of the area where the house is located. There are areas where heating is barely used and some even do not have this system, since it is unnecessary.

Centralized heating, as we mentioned in the case of air conditioning, is much more efficient and economical from an energy point of view than individual systems.

In winter, a temperature of 20ºC is enough to have a comfortable home.

Heating systems

Boilers and water radiators

Depending on the type of combustion there are different types of boilers:

  • Atmospheric: when the combustion is carried out in contact with the air of the room where the boiler is located. Since 2010, the purchase of this type of boilers has been prohibited.
  • Airtight: when air admission and gas evacuation take place in a closed chamber, without any contact with the local air in which it is installed. This type of boiler has higher performance than the atmospheric ones.
  • Boilers with automatic flame modulation: they reduce the starts and stops of the boiler, saving energy by adapting the heat to the needs, through a flame power control system.
  • Low temperature boilers: they work with low water return temperatures of around 40 and 60ºC, and with a low smoke temperature between 90 and 120 ºC, with higher efficiencies. Its main application is in facilities where a high number of hours can be worked at low temperatures in the hot water circuit.
  • Condensing boilers: recover part of the heat of combustion, particularly the latent heat of the water vapor that is produced during the process. Its optimal operating temperature is between 30 and 50ºC of the heating circuit. Another property is that they emit almost cold smoke at temperatures of 40-60ºC.

Alternative heating systems:

  1. Underfloor heating systems: hot water radiators are replaced by a plastic tube through which hot water circulates, embedded in the floor slab. In this way the ground becomes a heat emitter. The temperature to which the water must be heated is much lower (generally between 35 and 45ºC).
  2. Electric systems:
    • Radiators and Convectors
      • These are independent equipment in which heating is carried out by means of electrical resistances. From the global point of view of greenhouse gas emissions, they are not advisable due to the nature of the electricity generation park in Spain.
    • Electric radiant thread
      • As in the previous case, heating is carried out by passing electric current through a wire or resistance (Joule Effect). It is an expensive system to use and inefficient from the global point of view of the electrical system.
  3. Heat pump system: Normally it is about independent equipment, although centralized systems are much more efficient, in which the heat transferred by the heat pump is distributed by a network of air ducts and grilles or diffusers ( the most usual), or through tubes with hot water through which air is passed. The so-called "inverter" equipment regulates the power with variation of the electrical frequency, save energy and are more efficient with low outside temperatures.
  4. Electric heating by accumulation: It is based on the heating of refractory material by electrical resistances, the heat is stored inside the accumulators and is released when it is needed, by passing air through the refractory material, through natural convection in the case of static or fan-driven accumulators, in dynamic ones, which accelerates the output of hot water.

Practical tips to save energy in heating

  • Turn off the heating at night when you go to bed, when you get up, do not turn it on until your house has been ventilated and you have closed the windows.
  • Use programmer thermostats, these instruments are very easy to use and can lead to savings of between 8 and 13%.
  • If you leave the house for a few hours, you should leave the temperature at 15ºC.
  • The air that is stored inside the radiators makes it difficult to transmit hot water to the outside. It is convenient to bleed this air at least once a year, at the beginning of the heating season. As soon as air stops coming out and only water starts coming out, the purge will have finished.
  • Radiators should not be covered because it makes it difficult for air to escape.
  • The ventilation time of each of the rooms in a house should not exceed 10 minutes if we do not want to lose the heat accumulated in our home.
  • Do not put the heating above 20ºC. It is not healthy and also wastes energy!

Practical tips to save energy in air conditioning

  • Disconnect the air if you leave home or the room where it is located.
  • Not all homes need an air conditioner, perhaps a fan will suffice.
  • Do not put the air conditioning at less than 25ºC.
  • When you turn on the air conditioner, do not set the thermostat to a lower temperature than normal, it will not cool sooner and will waste unnecessary energy
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