The first great heatwave of 2021 is here, a climatological event that brings us record temperatures both outside and inside the house. If we have air conditioning or if we are considering buying a model to pass these days, it is probably the best system to cool the house quickly, efficiently and with which to maintain a comfortable temperature, although this comfort comes at a cost. .

With electricity prices soaring, also breaking record after record in recent weeks, even the new electricity bill cannot help us reduce the cost of having air conditioning on all day at home. Is it really that expensive to use?

Next, we are going to calculate how much it can be assumed to have the worst-case (most expensive) air conditioning system turned on at home all the time and taking some previous considerations into account. For example, let’s assume that we have a mid-range model with power consumption in the order of 1000 watts (1 KWh) at full capacity. The specific model you have at home may exceed or fall below this number, depending on its efficiency and age.

Also, probably if it is an Inverter type or a smart running model, it will not run at maximum power all the time, but will have intermediate cycles with much lower consumption that will easily drop to 30 or 40%. But for the purposes of these calculations, we will put ourselves in the worst case as we said previously.

We will also assume that we only have one air conditioner in the house. If we have more installed, then we will have to multiply by the total number of devices that corresponds to our specific case. In addition, we will consider that it will work during this heatwave 24 hours a day, which probably will not be true, because at night we can turn it off or leave it on intermittently spending less, but again we we will put in the maximum possible consumption.

We start the calculations

Alright, to begin with, the first thing we need to do is find out the cost of each KWh of electricity we are going to consume, a figure that varies every hour of the day and will depend on each power company, but that we can average today, in the At the time of this writing, with the following values ​​according to what is marked on the website of the Spanish Electricity Network in the three fixed sections: “punta, llano y valle” :

Cost in off-peak hours: 0.13 € / kWh Cost in fixed hours: 0.18 € / kWh Cost in peak hours: 0.27 € / kWh

The peak period is when the cost of tolls and charges will be the highest, it lasts 8 hours and is between 10 a.m. and 2 p.m. and 6 p.m. and 10 p.m. The flat section lasts an additional 8 hours, has an intermediate cost and lasts between 8 and 10 hours, 14 and 18 hours and between 22 and 24 hours. Finally, we will have the valley tariff, another 8 hours, which is the cheapest period and includes between midnight and 8 a.m. as well as during all hours on weekends and on public holidays.

Taking all this into account, our 1 KWh air conditioner will work every day for 8 hours with a consumption of 0.13 € / kWh, 8 additional hours with a consumption of 0.18 € / kWh and 8 additional hours with a ratio of 0 , 27 € / kWh. This comes down to around 1.04 euros, 1.44 euros and 2.16 euros respectively, which together gives us a figure that hovers around 4.64 euros.

Keep in mind that this figure is a worst-case scenario with air flowing all day without rest and with an average consumption of 1000 watts, so in your particular cases the figure may be somewhat different.

How to cut expenses without giving up air

It might not seem like much, but if, as we said before, we have multiple computers turned on, the amount can skyrocket. In addition, we must consider that it is every day, so if the heatwave lasts 4 or 5 days we may speak of an additional 24 euros on our next bill.

Can the expense be reduced? Well, we can try to program the equipment to work with lower target temperature in lower cost times and higher temperature when higher price. For example, we can make them run at maximum during the night and in off-peak hours with lower than theoretically ideal temperatures of 25 degrees, then increase the temperature during peak hours to 26-27 degrees.

We can also set higher temperatures than usual and supplement the cooling with a traditional fan which, with generally much lower consumption, will help us have a more comfortable thermal sensation.

Cover photo | Alexandre lecocq