What is the ideal heating temperature during the day?

According to the Institute for the Diversification and Saving of Energy (IDAE), the ideal temperature for being at home in winter is between 20 ºC and 21 ºC.

Keeping the thermostat in this range and wearing seasonally appropriate clothing, such as a light jumper, allows you to achieve ideal thermal comfort without using too much energy.

Is it mandatory to set my home heating to 19 ºC?

This limit, set by Royal Decree-Law 14/2022 to ensure temperatures do not exceed 19 ºC, applies exclusively to public, administrative, commercial and cultural buildings.

In private homes, there is no legal obligation to keep the temperature at 19 ºC, although building regulations do set out indicative and voluntary limits.

How much does consumption increase by turning the heating up one degree?

If you are wondering how much you can save by turning down the heating, data from the IDAE suggests that for every degree we lower the temperature in our homes during winter, consumption drops by around 7%.

Following this logic, we can deduce that setting the thermostat to 19 or 20 ºC generates greater financial savings than setting it to 21 ºC.

So, is it better to set the heating to 19, 20 or 21 ºC?

As we saw at the beginning of the article, the recommended sweet spot for combining comfort and efficiency is between 20 and 21 ºC. In winter, every degree over 20 ºC will potentially increase your heating system's consumption. It is up to each person to find the perfect balance for their home.

Does turning the heating up to 25 ºC make the house heat up faster?

The belief that setting the heating to 25 ºC heats a room up faster is a complete myth. Heating systems emit heat at a constant or modulated rate regardless of the temperature set. Turning the dial up to 25 ºC does not speed up the process; it only causes the system to keep using energy until it reaches an excessive and inefficient temperature.

What temperature should you set the heating to at night?

As we sleep tucked up under the covers, we can afford to programme the heating to a substantially lower temperature than during the day.

To guarantee a healthy and restful night's sleep, the IDAE's general recommendation is between 15 and 17 ºC.

Is it better to turn the heating off at night or leave it on low?

Turning the heating off completely before going to sleep and turning it on briefly when you wake up is more efficient than keeping it running all night.

An exception could apply to poorly insulated homes or those located in extremely cold areas, where it is advisable to leave it on a minimum setting (between 15 and 17 ºC) to prevent sudden drops in temperature.

What temperature should you leave the heating at when you are not at home?

The heating temperature you should set when you are out will depend precisely on how long you will be away:

• If you are going to be away for between 2 and 12 hours (when you go to work, for example): it is advisable to turn the thermostat down to around 15 ºC or to the 'Economy' setting, which is included on many models.
• If the house is going to be empty for several days (when you go on holiday, for example): it is best to turn the heating off or keep it on the minimum anti-frost setting of 7 ºC.

The ideal temperature: how to achieve it depending on your heating system

The equipment you have in your home will determine its response time and energy management:

• Boiler and radiators: Gas or oil boilers heat water that flows to iron, aluminium or steel radiators, providing a progressive and comfortable distribution of heat.
• Heat pump: Aerothermal systems and heat pumps extract energy from the outside air, standing out for their extremely high efficiency and speed when heating rooms.
• Underfloor heating: Underfloor heating distributes heat evenly through pipes under the floor, operating at low temperatures and providing high thermal inertia.
• Electric radiators: Electric heaters and radiators are easy to install and suitable for small flats or mild climates, although their direct electricity consumption is higher.

Do not confuse the thermostat temperature with the boiler water temperature

The thermostat temperature, which indicates the temperature of the room itself (the ambient temperature of 20–21 ºC we mentioned earlier, for example), is one thing, and the temperature of the boiler or radiators is another. In conventional boilers, the water can flow at around 60–80 ºC, while in condensing boilers and aerothermal systems, it operates at between 35 and 50 ºC.

Thermostat, thermostatic valve and boiler: what each one controls

Each component serves a specific purpose within the installation:

• Boiler: Generates heat and regulates the flow temperature of the water to the heating circuits.
• Room thermostat: Measures the air temperature in a central location and gives the overall command to turn the system on or off.
• Thermostatic valve: Located on each radiator, this regulates the flow of water entering the emitter to adjust the temperature room by room.

Do all rooms need to be at the same temperature?

Not necessarily. The temperature should be adapted to what each room is used for. For example, the living room temperature in winter will need those 20 ºC to 21 ºC we mentioned, as it is the main living area. Meanwhile, the bedroom temperature should be kept cooler, between 17 ºC and 18 ºC. Hallways or other unused rooms can be kept even cooler.

How to maintain different temperatures in each room

To manage the temperature of your house room by room, it is best to install thermostatic valves on the radiators in each bedroom or in the living room.

This will allow you to regulate the flow of water between the radiators in different rooms and direct the flow as needed.

Programme different temperatures for day and night

If your heating system has a thermostat with a daily timer, you can automate temperature changes according to the recommendations.

It is very simple: you just have to set the system to go up to 20–21 ºC shortly before your alarm goes off or before you get home from work, and then drop to 17–18 ºC a couple of hours before you go to bed.

Where to place your thermostat for reliable temperature readings

The location of your thermostat is crucial: ideally, it should be placed on an internal wall in the main room (such as the living room), away from direct sunlight, draughts and sources of heat or cold (such as radiators and windows) so as not to trick the thermal sensor.

Why might you feel cold even if the thermostat says 20 ºC?

If you set your heating to 20 ºC during the day, it might still feel cold if the relative humidity drops below 40% or if there are draughts from windows that create the 'cold wall effect', which is the sensation of cold we feel when we get close to an exterior wall with a window.

For perfect comfort, the ideal humidity level should be between 40% and 50%.

Check this before turning up the heating if you feel cold at 20–21 ºC

Before increasing the temperature setting, carry out these basic checks:

• Wear light, warm clothing suitable for being indoors.
• Check that the radiators have been bled and are free of obstructions such as furniture or curtains.
• Close blinds and curtains at dusk to improve insulation.

Calculate how much it costs to turn up the heating by one degree

Thanks to the SPAHOUSEC II report, we know that the average annual consumption of natural gas in Spain varies depending on the equipment in each home. The general average consumption is around 5,097 kWh/year, but in homes with gas heating, hot water and cooking, this figure rises to 7,921 kWh/year. In these homes, heating accounts for 57.1% of the total, which is around 4,522 kWh/year.

If we take into account the current price of our Conecta Gas tariff, which is €0.0845/kWh in September 2026, we can do the maths:

4,522 kWh/year x €0.0845/kWh = €382.10/year on heating alone

So, if turning up the temperature by one degree increases consumption by 7%, we can deduce that for every degree, your bill could go up by around €26.75 a year. You can check your estimated costs depending on the temperature in the following table: