From sunset to sunrise: how much energy does a home use while we sleep?

When evening arrives, the lights go out, the television and computer are switched off, and the smartphone is placed on the bedside table, often charging. The house seems still, but the electrical system continues to operate.

The refrigerator, modem, devices on standby, security systems and climate-control equipment may remain active overnight. Some need to operate without interruption, while others continue receiving power to maintain certain functions. Understanding what happens during these hours therefore helps us read household consumption more accurately.

Let us imagine an ordinary evening. The television is switched off, the computer is closed, the lights in the rooms go out and only the necessary appliances remain on in the kitchen. From this moment, it becomes easier to notice how much electricity is still being used.

Many devices can remain connected to the power supply even when they are not being used directly. The television may stay on standby, as may a games console or computer. The modem continues to provide the connection, while smartphones and smartwatches may spend the night charging.

The appliances that may remain connected include:

There is also an appliance that continues performing its function overnight regardless of what the people in the home are doing: the refrigerator, together with the freezer.

Even when nobody opens the door, the refrigeration system operates to keep the internal temperature stable. It works through automatic cycles, with periods when the compressor runs and others when it stops.

The refrigerator is therefore a useful example for distinguishing necessary consumption from avoidable consumption. Its power supply must remain active to preserve food properly. The same principle applies to other devices whose functions require continuous operation, such as some security systems or specific household equipment.

The fact that a home is quiet and apparently inactive does not mean that every appliance is switched off.

During the night, several areas of the home continue to use energy. In the kitchen, the refrigerator remains on, while in the bedroom smartphones, smartwatches and lamps may remain connected to the power supply.

In the living room, the television, soundbar, games console and decoder may also remain on standby, as can computers, monitors and printers in the study. Night-time consumption is therefore often the sum of many small uses, some necessary and others connected with the choice to leave devices ready for use.

Establishing one night-time consumption figure for every home would be unrealistic. A home with only a few connected appliances will have very different needs from one equipped with numerous electronic devices, climate-control systems and appliances that remain active throughout the night.

The length of the night naturally matters as well. An appliance that remains active for eight hours every night accumulates a significant number of operating hours over the course of a month.

To understand the real impact of night-time consumption, however, it is also necessary to look beyond the individual appliance. Having an overall view of one’s energy supply makes it easier to interpret consumption and identify the items that have the greatest impact. Suppliers such as Acea Energia, for example, offer plans designed for different needs, allowing people to adapt their choice of supply to the requirements of the household. Assessing the supply according to the characteristics of the home and the way energy is used can therefore be another factor to consider alongside the management of individual devices.

Consumption nevertheless remains mainly linked to the appliances in the home and how they are used. Knowing which devices remain active at night helps distinguish necessary functions from those that can be reduced or managed differently.

This step is important above all for one reason. Knowing one’s energy supply makes it possible to combine simple observation of appliances with a more complete reading of household consumption. The supplier, naturally, does not determine how much energy a refrigerator uses or how long a television remains switched on. Consumption is determined by the characteristics of the appliances and how they are used.

At three in the morning, the situation changes again. Household activities have stopped, nobody is using the kitchen and the lights are off. Consumption continues, however, through appliances that need to remain operational.

The refrigerator continues its cycles, the modem keeps the connection active and some devices remain on standby. If a climate-control system is switched on, its operation may have a more noticeable effect on night-time consumption.

This phase makes it possible to distinguish between two categories. On one side are appliances that perform a specific function even while the home is asleep. On the other are devices that remain powered simply because nobody has unplugged them or switched them off completely.

The difference may seem small over a single night, but it becomes more significant when the same behaviour is repeated for weeks.

During summer nights, consumption may increase if temperatures remain high. An air conditioner may stay on for several hours, and its impact depends on its power, the set temperature, efficiency, room size and the insulation of the home.

A fan performs a different function, encouraging air circulation without directly lowering the temperature. A dehumidifier acts on humidity and can be useful in particularly damp rooms. For both appliances, power and operating time affect consumption.

Reducing night-time consumption begins with a simple question: which appliances really need to remain active?

Before going to bed, people can check the devices in the different rooms and switch off those that can be turned off without compromising a necessary function. Some solutions are particularly simple:

The same attention should not be applied to appliances that require a continuous power supply. Refrigerators, security systems and other essential devices must be able to perform their function regularly.

Even at night, part of the electrical system continues to operate. The refrigerator, internet connection, standby devices and climate-control equipment may remain active while everyone sleeps. Knowing which appliances use energy helps distinguish necessary consumption from consumption that can be reduced.