Keeping Windows closed throughout the day can help retain heat, but it also prevents indoor air from being renewed. Humidity and odors continue to build up during winter, making ventilation necessary. The challenge is to bring in outside air without cooling the home more than needed.
Ventilation can be less efficient when it is carried out while the heating is running. Opening a window changes the temperature of a room, and the heating system may then have to compensate for the lost warmth. The layout of the home, the doors connecting rooms and the outdoor temperature also influence the result.
One mistake is choosing the coldest part of the day to open the windows. Temperatures are often lower at dawn and in the evening, increasing the difference between indoor and outdoor conditions. When ventilation can be scheduled, the middle of the day may be more suitable. Sunlight can also help retain warmth, depending on the home's orientation and the weather. This does not mean delaying ventilation when it is needed to remove odors or humidity.
Another error is leaving radiators on while airing a room. Heat can escape as cold air enters, and the system may continue using energy without retaining that warmth indoors. Where the controls allow it, the heating can be switched off before opening the windows and turned back on after they are closed. Ventilating in the morning before starting the radiators is another possible option.
Opening every window without planning the route of the air can also cool more of the home than necessary. Ventilation can be organized by rooms, limiting connections with other areas and moving on once each space has been aired. Cross-ventilation may speed up air renewal when used briefly, but leaving several windows open without considering airflow or duration can increase heat loss.
Keeping windows open longer than necessary is a further mistake. Once the air has been exchanged, additional time can cool floors, walls and furniture, which then require more heat to warm up again. Winter ventilation is generally better concentrated into a few minutes than carried out by leaving a window slightly open all morning. Five to ten minutes is often used as a reference, although the appropriate time depends on the home's layout, air circulation and other characteristics.
Finally, leaving the doors of unused rooms open can affect how heat is distributed. Warm air may reach areas that do not need to be kept at the same temperature, while colder rooms can reduce the temperature elsewhere. Closing doors to little-used spaces helps separate environments and limit unnecessary exchanges. The aim is not to keep every door closed permanently, but to control communication between rooms according to how they are being used.
Sources: elDiario.es.