Which consumes more electricity, the fan or the air conditioning?

BarcelonaWith summer, it’s time to turn on the fan. Or air conditioning. The debate over which of the two types of device is best for soothing the heat will surely never end, but we can know which is best for our pocket.

The first question to consider is whether the air conditioner has built-in technology inverter or not. This technology reduces consumption quite significantly, in some cases up to 40%, as it regulates the speed of the appliance compressor to keep the room temperature stable. Airs that do not incorporate this technology have a constant consumption until they stop when the temperature marked on the thermostat is reached. This regulation avoids excessive consumption when the temperature of the space rises very quickly or when the air conditioning cools too quickly. In the case of appliances inverter, calculating consumption is very difficult, precisely because energy expenditure is not constant. In others, however, it is easier.

Another problem with making home consumption calculations is the bustle of different units. One thing is the watts of power; another is the consumption, which is in kilowatt hours (kWh), and a third, the cooling capacity of the appliance, which is expressed in refrigeration. One kilowatt is transformable to 860 refrigerators.

The fan wears out like a light bulb

The energy consumption between the two appliances has no point of comparison. The vast majority of fans have a power of between 40 and 100 watts, that is, more or less equivalent to a light bulb. With these figures, if we keep a fan running for eight hours straight, the power consumption will be between 0.32 kWh for a 40 watt appliance (40 watts multiplied by 8 hours is 320 watts an hour, or 0.32 kilowatt hours ) and 0.8 kWh if the power is 100 watts. With the average price of light this Friday with regulated rate, which was 0.312 euros per kWh, the cost of the eight hours of fan moves between 9 and 24 cents, without taking into account tolls or taxes.

According to data from the energy company Selectra in 2018, during the summer months a Spanish home has the air conditioning on for about six hours a day for workers and about eight hours on Saturdays and holidays. The calculation, however, includes households in the Basque Country or Cantabria, where it is less hot than in Catalonia, and in Andalusia or Murcia, where it is much hotter, so it is necessary to take the data with caution, with the addition that in Catalonia there is also a lot of climate disparity by counties. Also, not all years are the same: so far we have suffered several heat waves, but other years the temperatures have been more moderate.

Consumption will also depend on the efficiency of the home. In this sense, cooling the room in a well-insulated building will lead to lower consumption. Likewise, if it is oriented to the north – in the south it will have more hours of direct impact of the sun – less energy will also be needed to cool the chamber.

In general, manufacturers estimate that, on average, for every square meter it takes about 100 cold refrigerators to put it at a pleasant temperature, but again we find the problem that this depends on each home, the municipality, the hours of the day and efficiency. That is, about 50 square feet (roughly a large room and a spacious living room) will need an appliance with a cooling capacity of 5,000 refrigerators, or 5.81 kilowatts.

If a family has an air conditioner with this cooling power on for six hours, the cold generated will be equivalent to 34.86 kWh. If you turn it on for eight hours, the figure will increase to 46.48 kWh.

The SEER marks the cost

This is where SEER comes into play – the acronym for seasonal energy efficiency ratio, which is the coefficient between the cold energy generated by the device and the energy consumed in electricity, according to the Japanese manufacturer Toshiba. That is, if for every kilowatt hour of electricity consumed by the appliance two kilowatt hours of cold are generated, the SEER is two. The higher the SEER of the device, the more efficient it will be. In terms of energy label, an air conditioner with an SEER greater than 8.5 (for every kilowatt hour spent on electricity will generate 8.5 kilowatt hours) has the highest rating (A +++), while the lowest ( E) is for a SEER below 3.6.

Therefore, for 34.86 kWh of cold generated, an air conditioner with an SEER of 8.5 will consume 4.1 kWh of electricity, while for 46.48 kWh of cold generated in eight hours, electricity consumption will rise to 5.46 kWh. Translated into euros, it costs between 1.28 and 1.70 euros. That is, the cost of consuming a highly efficient air conditioner is about seven times higher than that of a large fan. With air conditioning with a SEER of 3.6, however, consumption rises to 4.02 euros for eight hours of operation, sixteen times more.


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