Buildings account for a staggering 40% of the world’s total energy consumption, making them natural potential targets. Hvac systems alone (i.e., heating, ventilation and air conditioning) account for 38 percent of a building’s energy consumption. Today’s world urgently needs to move in a more sustainable direction, so the opportunity to improve the energy efficiency of HVAC systems becomes impossible to ignore. Let’s take a look at the future development of ventilation.

Energy efficient on-demand ventilation

There are many scientific and technical definitions of ventilation, but the main goal is to introduce clean outdoor air while removing pollutants produced indoors. The energy efficiency of different ventilation systems varies. Demand controlled ventilation adjusts airflow rates against demand based on accurate CO2 measurements. This means that the average airflow rate is lower, there is no over – or under-ventilation, and less energy is required for fan operation, heating, and cooling.

In fact, a demand-controlled ventilation system with CO2 concentration control can save more than 50% of energy compared to a constant air volume system. In addition, the system can also keep the indoor temperature at a comfortable level for building users. Such systems ensure that ventilation levels are always good, even when occupancy levels change over time – the system increases ventilation when CO2 levels are high and decreases ventilation when they are low.

The importance of clean, healthy air

Saving energy is crucial, but it’s not the only important factor to consider. Indoor air quality can also cause health problems – airborne transmission is a major mode of transmission of various respiratory infections, so paying attention to the way buildings are designed, operated and maintained is crucial to minimize the spread of airborne infectious diseases. People are often unaware of the impact of ventilation and indoor air quality on building users. For example, scientific studies have shown that improving ventilation and air quality can:

• Improve health and reduce sick leave rates

• Relief of sick building syndrome

• Improve personnel performance and productivity

• Improved sleep quality

Therefore, it is important to maintain clean air and low concentrations of carbon dioxide in the occupied space, and increased productivity can have a significant impact on the company’s bottom line.

Consider outdoor air quality

People are paying more and more attention to how to prevent outdoor air pollution from affecting indoor air quality. Outdoor air quality can vary greatly at different points of the day or year. When the outdoor air is clean, ventilation should be increased, and when the outdoor air quality is poor, ventilation should be reduced or even stopped. In these cases, indoor air should be recirculated to prevent contaminated air from entering the system.

In the future, ventilation will need to be controlled more frequently based on outdoor air quality. This is because, for many indoor pollutants, it is the average exposure, not the peak, that determines the risk. This means that sometimes it is best to reduce the number of ventilation, indoor air after a few hours after the pollution level increases, then through outdoor air ventilation, thereby reducing indoor air pollution levels. To achieve these goals, monitoring air quality and controlling ventilation are essential.

Look to the future

The European Performance Directive, which will be amended in 2023, stipulates that indoor air quality should be measured and controlled. In the next few years, member states will make the directive mandatory for all new buildings. About 30 percent of new buildings currently use demand-controlled ventilation, but experts predict that figure will rise to 50 percent or more in the next 10 years.

Ventilation is just one of a growing number of indoor air quality-based control measures that will be taken into account in the future, along with the prevention of airborne infections, future ventilation guidelines and building codes. In the coming decades, many new regulations are likely to be introduced around the world to ensure clean indoor air.

A reliable sensor

As mentioned earlier, CO2 measurements can indirectly indicate indoor air quality and the effectiveness of ventilation systems. To measure CO2 levels, you need a reliable sensor, and the sensor position should ensure that the reading accurately indicates the air quality of the room. A common mistake is that the sensor’s mounting position is exposed to the intake airflow (i.e. clean air). Another common mistake is to install a low-quality sensor in the return air duct, which exposes the sensor to a large amount of house dust, potentially leading to failure.

Vaisala CARBOCAP® sensors use sensor elements that maintain long-term measurement stability and are not sensitive to dirt or dust. This sensor is therefore very reliable and ideal for demand control ventilation systems.

Can your building benefit from this?

Demand controlled ventilation helps improve the air quality and energy efficiency of buildings by ensuring that ventilation is only available when it is truly needed. Buildings with variable occupancy loads will benefit, including most office buildings with post-pandemic working practices. But virtually any building that people live in, work in, or visit can benefit from demand-controlled ventilation because of the system’s ability to improve energy efficiency and air quality.