.How you maintain or improve ventilation will depend on the space and building. Buildings are ventilated by natural systems such as vents, windows and chimneys, or by mechanical systems such as extractor fans or air conditioning, or a combination of both.
Where it is not possible to bring in more fresh air, a high efficiency particulate air (HEPA) or ultraviolet (UV) air cleaner could in some cases be useful for reducing the risk of infection.Ventilation in the home is most important when someone in your household has COVID-19 or another respiratory infection, or when you have visitors to your household.Opening windows and doors at home is the simplest way of improving ventilation for most people.If windows have openings at both the top and the bottom (such as sash windows), using just the top opening will help incoming fresh air warm up as it mixes with room air, reducing cold draughts.
In warmer weather, use both the top and bottom openings as this will help provide even more airflow. Opening windows and doors at opposite sides of your room or home will also provide a good flow of fresh air (this is known as cross ventilation).Check whether trickle vents (small vents usually on the top of a window) or grilles are open and not blocked.
Air which flows in from these vents will mix with warm room air as it enters, which helps keep the room a comfortable temperature.Windows do not need to be open all the time to improve ventilation.