Overview of the different types of decentralised ventilation systems

Planning efficient ventilation systems is essential for modern buildings. A key challenge here is to balance adequate fresh air supply with energy efficiency. Decentralised ventilation systems offer flexible, adaptable solutions. In this article, we take a look at the different types of decentralised ventilation systems and examine how they work, as well as their advantages and disadvantages. Whether passive air transfer units, decentralised ventilation systems with or without heat recovery – our expertise will give you a comprehensive overview of the wide range of options.

Passive air transfer units (ALD)

How they work: passive air transfer units use the natural difference in air pressure between inside and outside to ensure a continuous supply of fresh air. They require no electricity and no mechanical components. Advantages:

• Energy independence: Because they don’t require active ventilation, there are no operating costs for electricity or maintenance costs for moving parts.
• Sound insulation: Modern air diffusers usually provide a high level of sound insulation, making them ideal for noisy environments.
• Easy installation: Particularly suitable for new buildings and renovations, as they do not require complex ventilation shafts.

Fields of application: ALD systems are ideal for residential buildings and less complex buildings where basic ventilation is required but there are no high demands on heat recovery. They are particularly suitable for apartment buildings or smaller projects where cost efficiency is a priority. With the AIR 000 series, Ventomaxx offers one of the most comprehensive product series of air transfer units on the market. The fully modular concept allows for a nearly unlimited range of applications.

Decentralised ventilation systems with heat recovery

How it works: These systems actively use fans and contain integrated heat exchangers that use the heat from the outgoing air to preheat the incoming fresh air. This significantly reduces the energy required for heating. Advantages:

• Energy savings: Heat recovery can recover up to 90% of the heat contained in the outgoing air, which drastically reduces the heating requirement, particularly in energy-efficient new buildings and renovations.
• Good air quality: The continuous air exchange ensures consistent air quality without losing heating energy.
• Comfort: A higher level of thermal comfort is achieved by heating the incoming air, which minimises cold draughts.

Areas of application: These systems are ideal for energy-efficient new buildings, passive houses and renovations where strict energy requirements apply. They are a preferred choice in particular in buildings that are to meet KfW standards or the passive house standard. They are also particularly popular in commercial properties, offices and educational institutions due to their efficiency and high level of comfort. Decentralised ventilation units from Ventomaxx with heat recovery are available as the WRG RONDO, WRG PLUS and WRG MAKANI® R / Q series. They stand for high-quality, decentralised ventilation comfort with extremely energy-efficient heat recovery and above-average protection against outside noise.

Decentralised ventilation systems without heat recovery

Functionality: These systems also work actively, but they do not have a heat exchanger. They effectively ventilate rooms by extracting stale air and supplying fresh air without using the heat from the outgoing air. Advantages:

• Lower purchase price: Because they don’t have a heat exchanger, these systems are less expensive than heat recovery models.
• Easy to install: Without a heat exchanger, the systems are more compact and easier to install, which simplifies planning and implementation.
• Effective ventilation: Even without heat recovery, they provide constant air exchange, which helps to improve air quality.

Areas of application: These solutions are suitable for buildings or rooms in which permanent basic ventilation is necessary but there are no strict requirements for energy efficiency. Examples include workshops, storage rooms or public buildings where temperature control plays a subordinate role. The ECO COMFORT series, optionally available with a PLUS DESIGN or IQDESIGN cover, are the solutions from the extract air sector for all rooms with odour and moisture contamination with the highest comfort requirements (rest rooms, kitchen, bathroom, toilet, etc.). Fully integrated into the outer wall, the extract air units have a very high passive sound insulation of up to 55 dB, Dn,e,w.

The key aspects at a glance

Decentralised ventilation systems provide a versatile and efficient solution for ventilating buildings. Unlike centralised ventilation systems, which use a centralised fan to move air, decentralised ventilation systems operate independently to provide fresh air to individual rooms. There are different types of decentralised ventilation systems, each offering different advantages. All three ventilation solutions have their specific advantages and are suitable for different applications:

• passive outside air inlets are ideal for simple ventilation requirements where energy efficiency is less relevant, but sound insulation and easy installation are paramount.
• Decentralised ventilation systems with heat recovery offer maximum comfort and energy savings, but are more expensive and require more thorough planning.
• Decentralised ventilation systems without heat recovery represent a cost-effective alternative for buildings where temperature control is less important.

The choice of the appropriate system depends on the specific requirements of the project. TGA specialist planners should therefore carefully weigh up the factors of energy savings, comfort, installation and operating costs in order to find the optimal solution for their construction projects.  

Criterion	Passive Air Vents	Decentralized Ventilation System with Heat Recovery	Decentralized Ventilation System without Heat Recovery
Air Supply	Natural ventilation, passive fresh air supply	Mechanical supply and exhaust air with heat recovery	Mechanical supply and exhaust air without heat recovery
Heat Recovery	None	Up to 90% heat recovery	None
Energy Efficiency	Energy loss due to uncontrolled fresh air supply	Very efficient, as heating energy is saved through recovery	Less efficient, as no heat recovery takes place
Installation Effort	Simple and cost-effective, no power connections needed	More complex, requires power connection and installation of heat exchanger	Flexible use in various building types, including older buildings, requires power connection but no heat recovery components
Acoustics / Sound Insulation	Very good sound insulation possible, ideal for noisy areas	Good sound insulation, quiet operation modes possible	Noise emissions from fans possible
Maintenance Effort	Minimal maintenance, occasional filter change	Regular filter changes and maintenance of heat recovery unit required	Regular filter changes, but no heat recovery maintenance needed
Cost (Purchase / Operation)	Low purchase cost, no operating costs	Higher purchase cost, low electricity consumption, savings on heating costs	Moderate purchase cost, higher electricity consumption, no heating cost savings
Application Area	Suitable for new builds and retrofitting, ideal for small to medium-sized rooms	Suitable for energy-efficient new builds and renovations	Flexible use in various building types, including older buildings
Sustainability	Less energy efficient but low-maintenance and durable	Very sustainable through energy savings and reduced CO₂ emissions	No energy savings through heat recovery
Integration into Smart Home Systems	No direct integration possible	Fully integrable, automatic control via sensors	Partially integrable, depends on the system

Further aspects in focus

Environmental aspects and sustainability Climate change and rising energy costs are increasingly drawing attention to the sustainability of ventilation systems. Decentralised ventilation systems play a key role here, as they offer energy-efficient ventilation solutions that help to reduce CO₂ emissions. Energy savings through heat recovery:

• Heat recovery systems are particularly energy efficient and can reduce heating energy demand by up to 90%. This results in significant savings in primary energy and simultaneously reduces a building’s CO₂ emissions.
• The use of renewable energy to power ventilation systems can further improve the carbon footprint.

Materials and resources:

• Many decentralised ventilation systems are made from durable, recyclable materials, which further increases their environmental friendliness. Manufacturers are increasingly focusing on sustainable production processes and trying to minimise the ecological footprint of their products.
• Filters in ventilation systems need to be changed regularly, which requires resources. Some manufacturers offer recyclable or biodegradable filters to reduce environmental impact.

Air quality and health:

• In addition to energy efficiency, decentralised ventilation systems also help to improve indoor air quality, which has a direct impact on the health and well-being of residents. A healthy indoor climate not only promotes productivity, but also reduces health risks associated with poor air quality.

Decentralised ventilation systems are an essential part of sustainable building design. In particular, systems with heat recovery offer enormous potential for reducing energy consumption and CO₂ emissions. TGA specialist planners should evaluate the sustainability of the systems used in order to implement future-proof and environmentally friendly solutions.

More exciting articles

The DIN 4109 standard is an essential factor in the sound insulation of ventilation systems. In a blog post by Ventomaxx, you can learn everything you need to know about DIN 4109 and its sound insulation requirements. Find out more at: DIN 4109: Sound insulation of ventilation systems. BAFA funding plays an important role in the area of ventilation. If you want to learn more about BAFA funding for ventilation in 2024, read Ventomaxx’s blog post. It covers all the important information from the requirements to how to apply: BAFA funding for ventilation in 2024: What you need to know. Another interesting article from Ventomaxx deals with the 5 most common mistakes when planning ventilation systems. Find out how to avoid typical mistakes to create an optimal ventilation solution. Read more here: The 5 most common mistakes when planning ventilation systems. The risk of mould in buildings should not be underestimated. In an informative article, Ventomaxx addresses the question of which mould is actually dangerous and what health risks it poses. Learn more about the different types of mould and how to recognise dangerous mould: Which mould is dangerous?. We are happy to support you in the initial phase of the planning process to ensure that the ideal individual ventilation solution can be implemented together with you. Provide us with your planning documents and we will support you from the beginning of your project to the handover and deliver the required solutions in the form of your customised Ventomaxx fan. Decentralised ventilation systems offer a wide range of options for improving air quality in living and working spaces. From passive outside air inlets to active ventilation systems with heat recovery, the possibilities are wide-ranging. Thanks to innovative technologies and well-thought-out design, these systems enable efficient ventilation and contribute to energy savings. With a particular focus on sound insulation and environmental aspects, decentralised ventilation systems offer a sustainable solution for a pleasant indoor climate. Discover the variety of decentralised ventilation systems and find the optimal solution for your individual needs.