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The hidden costs of staying cool at home with air conditioning

Altroconsumo's advice: the temperature should not be lower than 26 degrees and pay attention to the location

5 July 2025

Alcuni condizionatori sulla facciata di un palazzo a Roma. ANSA

3' min read

Penguin, split but how much do you cost me? Staying cool indoors is a priceless pleasure. No, there is a price and it can be very expensive. In fact, this summer, intensive use of the air conditioning system, day and night, can cost over 400 euros. In all cases, air conditioning is not a luxury, but a necessity when the elderly live at home and are at risk of heatstroke, while for younger people it is the only way to get a cool night's sleep. The coolness is there but the electricity bill flies and, according to calculations by Altroconsumo, Istat data and energy sources, the use of the air conditioner alone between June and August can raise the electricity bill by up to 400 euros more than in the winter months. A heavy increase that can be felt, especially in a context of generalised price rises.

In other words, considering an average electricity cost of around 0.35 euro/kWh, including taxes and system charges, the weight in the bill of the air conditioner alone can be put down to three orders of magnitude, depending precisely on how it is used. Someone who owns a small 9,000 Btu/h air conditioning unit and uses it for a couple of hours a day this summer will spend an extra 52 euros. With a more powerful 12,000 Btu/h unit kept on for eight hours a day, the bill increases by 280 euros, while with a multi-split system used for ten hours a day it easily exceeds 400 euros.

We start with the electricity consumption of a standard air conditioner, which varies between 750 and 1,100 watts per hour, but consumption can go up if the appliance is old, poorly positioned or forced to work in very hot environments such as when facing south. In three months, it can go from a low consumption of around 150 kWh for those who only switch it on a couple of hours a day up to 800 or even 1,200 kWh for multi-split or centralised systems that are used intensively.

There is no shortage of good news because compared to 2024 this summer, the average cost of electricity has remained more or less unchanged, a year ago it was around 0.31 euro/kWh compared to the current 0.32 euro/kWh; and even if the heat seems to have arrived a little earlier, the average temperatures are roughly in line with last year.

The Ways to Save

This equipment must be chosen carefully and requires a good level of maintenance. An oversized air conditioner in relation to the indoor environment will unnecessarily consume more energy, while an undersized one will be inefficient. This is why it is important to carefully evaluate the power in BTU/h in relation to the square metres to be cooled, but also the energy class, quietness and smart functions that help optimise consumption.

"To really limit consumption, the ideal is to set the air conditioner to no less than 26 °C, use it with the dehumidifier on sultry days, and clean the filters at the beginning of the season," explains Stefano Casiraghi, an Altroconsumo expert. "In this way you can save as much as 20-25% on your energy bill without sacrificing comfort. And remember to screen windows facing the sun with external blinds"..

The correct installation of the air conditioner plays a fundamental role: a badly positioned outdoor unit or incorrect pipe insulation can compromise efficiency and increase consumption. In many cases it is advisable to rely on a certified technician, especially if installing a fixed or trial split system. On the maintenance side of splits and outdoor units, on the other hand, it is essential to clean the filters regularly to avoid dust accumulation that reduces performance and can also generate unpleasant odours. In the event of a drop in performance, it may also be necessary to intervene with a recharge of the refrigerant gas. Those who cannot or do not want to install a stationary air conditioner can consider portable alternatives. They are not the most efficient choice, but for small rooms or for renters they can be a good compromise. The new models are quieter, have programmable functions and are also improved in terms of consumption: here is a comparison of which portable air conditioners are really worthwhile.Finally, it is good to consider installing awnings to minimise direct heat input, in this case the sun's rays: if blocked before entering the house through especially sunny windows, the savings in terms of air conditioner use are significant.