Double flow ventilation in winter, how can we improve our comfort at home?

Winter is coming and many people already fear two of the complications associated with low temperatures: possible health problems and the energy costs associated with heating. Health, obviously, suffers with the cold and in our homes the traditional climate control systems have always resulted in a large energy expenditure to combat these low temperatures. However, both problems can be solved by using double flow ventilation systems. Moreover, we can say that they are the best current solution to improve indoor air quality and also minimize energy consumption.

The construction sector is looking towards the necessary energy efficiency. Homes and workplaces are being built with better construction materials, a commitment to renewable energies, and an effort to eliminate energy expenditure as much as possible. It is no coincidence that in just over a year it will be mandatory for all buildings constructed in our country to be Nearly Zero Consumption Buildings. One of the measures that will be implicit in this will be the use of mechanical ventilation systems.

What does a double flow ventilation system imply for the home or our workplace?

• Improves the health of the people occupying the spaces.
• The air is filtered, making it much easier to breathe.
• Illnesses are avoided and the air is cleaned of germs, bacteria, and particles.
• It improves climate control in an ecological way. In winter, it’s possible to enjoy a milder temperature.

Before understanding what the double flow system is, it is important to understand what using mechanical ventilation means.

The mechanical ventilation systems are the most efficient way to renew air in buildings. They ensure the necessary health in our homes and workplaces, and there is no need to open windows. Their necessity will become apparent starting in 2020 with the implementation of legislation requiring all buildings to be nearly zero consumption. The need for ventilation systems is outlined in the Technical Building Code, in the Basic Document HS3.

The air in the rooms deteriorates regularly, and what mechanical ventilation systems do is extract it, allowing clean air to enter. In this regard, two important factors make them fundamentally different from traditional ventilation and air conditioning mechanisms:

1. Mechanical ventilation systems are always on, they don’t have an off button. This is because they have nothing to do with climate control systems; the renewal of air must be constant and never stop. Just like other appliances such as refrigerators. In the case of ventilation systems, the expenditure is minimal. In many cases, it is similar to that of a light bulb.
2. It is not necessary to open the windows. In fact, it is not recommended to do so except to go out onto the terrace or look further. The air inside the rooms will be better than outside.

At first, it may seem strange that the air indoors is cooler, but thanks to the renewal, we will never encounter bad odors or a feeling of being in a closed space. We will also live healthier.

The general operation involves one or more ducts that connect the outside with the inside. A unit extracts the air or pushes it. To understand this better, we need to look at the different solutions available.

What two predominant types of ventilation systems do we find?

• Simple flow mechanical ventilation systems. Air is extracted mechanically, with a unit that pushes it from the rooms to the outside. The introduction of outside air is done through ducts that connect with the rooms through ventilation grilles, as modern buildings are much more airtight and air does not filter easily.
• Double flow ventilation systems. In addition to mechanically extracting air, there is another duct that pushes air from the outside. Moreover, filters are installed to clean the outside air. Currently, double flow ventilation is the most efficient and the best solution also for acclimating a space.

Likewise, double flow ventilation solves most of the climate control problems in winter and also in summer, thanks to a heat and cold exchange system.

Advantages of double flow ventilation systems

As seen in the graph above, double flow mechanical ventilation systems are capable of introducing air through separate ducts from those through which the quality-degraded air is extracted.

Unlike simple flow systems -whose intake occurs directly from the outside through grilles-, double flow mechanical ventilation systems can introduce air according to the exact needs of each room. Automatically, both input and output ducts are combined to provide the necessary comfort at home, which is more pleasant, in addition to being healthy.

What are the main characteristics of double flow mechanical ventilation systems?

Automation of the air intake and exhaust

The double flow ventilation can be equipped with temperature and humidity sensors to control the exact situation of the air at all times. In this way, it is possible to know how much water vapor in the air or pollutant particles are present.

The ventilation systems adapt to the exact needs for air renewal, being able to stop the fans when necessary, increasing or decreasing their speed.

All this provides a greater sense of comfort, as well as ensuring health. Current buildings have greater airtightness, which makes air filtration from the outside difficult. This is advantageous for the double flow system, which can always introduce quality air.

Always clean and filtered air

The air found outdoors is not always beneficial for our body. In fact, it can be quite harmful if found in urban areas with a high concentration of traffic.

However, air in a closed room can be much more harmful, as the use of chemicals or cooking fumes can pollute the environment and end up developing stale air.

The double flow ventilation system is not only capable of eliminating low-quality air indoors. But it also filters the outside air before introducing it. This way, pollutant particles, as well as bacteria, are eliminated, and even access for mosquitoes is blocked.

One enjoys a clean and impurity-free environment at home, which has the following benefits:

• Greater concentration at work or at home.
• Better quality sleep and great relaxation.
• Protection against diseases and colds.
• Improvements in skin and in our bodies.
• Greater harmony and decreased irritability.

The CTE warns of the need to use a mechanical ventilation system to guarantee health in homes, partly due to the necessary airtightness of new buildings. However, it is the double flow ventilation that protects health the most and provides the greatest comfort.

Climate control in winter thanks to double flow ventilation

One of the greatest benefits that double flow ventilation provides, making the entire system one of the best ways to bet on energy efficiency, is its way of delivering heat in winter or refreshing in summer.

Thanks to the exchange of the air that exits through the extraction ducts with the air that transports the intake, an effect is produced that tempers the air introduced from the outside. What does that mean? Basically, even when being outside at very low temperatures, the air that enters the rooms is at pleasant temperatures.

All this without expenditure on climate control, in addition to avoiding the stagnation of hot or cold air in a particular zone of the room. This system also enables passive houses to have an efficient climate control system without the need for traditional climate control methods.

Likewise, in summer, the introduced air is also cooled to avoid high temperatures at home and not require the use of air conditioning. More or less, double flow ventilation systems can maintain a room's temperature at around 26ºC in summer and no lower than 21ºC in winter, although these figures will also depend on the geographical situation of the property, the weather at a specific moment, and the building itself.

Furthermore, air renewal provides other evident benefits. One of them, very important in winter, is that heat does not settle in a particular area of a room, as tends to happen with traditional climate control. By introducing warm air from the outside, it is evenly distributed throughout the rooms. Moreover, on a health level, in winter a double flow ventilation system helps combat colds and other respiratory problems.