In a Demand Controlled Ventilation (DCV) system the ventilation airflow is continuously matched with the actual demand. Airflow can be decreased or increased based on temperature, occupancy or air quality. By doing this, the DCV system uses on average less energy compared to a conventional Constant Air Volume flow (CAV) system.
DCV systems are often perceived as a solution for commercial premises. The bigger the variation between the minimum and peak loads, the more energy savings can be expected with a DCV system. This is the case in schools and office buildings, where rooms are crowded during peak hours and empty during nights and weekends. Even if there are obvious advantages with a DCV system, the system itself is somewhat more complex than a CAV system. A competent design and a careful installation, commissioning and maintenance are required to ensure the expected performance. This is why DCV may not seem as an attractive choice in residential use.
However, there are many functional benefits that are in favor of using DCV. Conventional ventilation systems rely on the user to change the airflows. In commercial buildings there can be real estate managers whose job it is to control ventilation, but in residential buildings there are only the private persons living in the apartment that needs to do the job. Working moms and dads, busy teenagers and relaxed retirees, who don’t want to worry about ventilation.
It is a fact that most people don’t actually decrease ventilation when they leave home. This could be handled fully automatically with a DCV system. To make life easier on one hand; to guarantee energy savings on the other. More importantly, DCV system can ensure that people inside the room have enough fresh and healthy air in different situations. It automatically increases the airflow when people come in, someone is taking a shower or starts cooking food. All this can be a significant benefit for both the property owner and the resident. Studies show that the airflow in a DCV system increases with up to 40% towards design airflows several times every day. This means that the recommended design airflows are not enough in a modern society where we shower more often, do laundry every day and have pets inhouse. In spite of that, since we are away most of the day, the average airflow in a DCV system is approximately 40% lower than the design CAV airflow.
Benefits for property owner:
- Lower energy consumption
- Less risk of moisture problems (less damage to building)
- Better air quality for residents (less complaints)
Benefits for residents:
- Better air quality (fresh air, better sleep, better health),
- Ease-of-use (e.g. automatic boost when you go to shower)
- No need to control airflow yourself (continuous air quality measurement)
A great thing about DCV is that it can be applied to various different buildings and ventilation solutions: centralized systems, semi-central systems, de-central systems as well as detached houses or summer cottages. These days you can even replace an old kitchen fan with a modern ventilation unit that exploits heat recovery and DVC functions.
So, Is DCV a smart investment in residential buildings? If you consider the well being of both the building itself, and the people living in it, the answer is definitely yes. When you look at the return of investment, the payback is longer than many real estate owners accepts. However, since the energy from our homes stands for such a big part of the total energy use, it is more of an environmental investment than a financial.
To learn more about different ventilation solutions check out the Guide to Residential Ventilation
P.S. For more information, get in touch with your local Swegon contact or visit Swegon.com