FAQ

Opening windows allows oxygen to enter the space. However, this does not always provide adequate air exchange.

To achieve proper ventilation, you would need to fully open the windows for at least 5 minutes every hour. This would apply during the day and at night, regardless of weather conditions.

According to the World Health Organization (WHO), around 99% of the global population breathes air that exceeds recommended air quality guideline levels.

Therefore, when you open windows, you do not bring in only oxygen. You also bring in allergens, dust, and pollutants.

At the same time, the energy used for heating or cooling escapes from the space.

In addition, it is unrealistic to expect someone to open and close windows every hour, including throughout the night.

For this reason, window ventilation is neither practical nor sustainable in real-life conditions.

CONFIRMATION

To learn more about this topic, read the blog post “Heat Recovery Ventilation: “Heat Recovery Ventilation: 8 Benefits for Your Home.”

This article explains the challenges of window ventilation and the advantages of advanced ventilation systems.

Therefore, Marquis Intelligence residential ventilation solutions use heat recovery to provide continuous fresh air with lower energy losses.

Marquis Intelligence residential ventilation systems reduce humidity, mould, and allergens.

At the same time, they protect the home from polluted outdoor air.

In addition, the systems are energy-efficient, quiet, and tailored to different types of residential spaces.

CONFIRMATION

In a newly built 100 m² flat in New Belgrade, Marquis Intelligence installed a ventilation system in just three days.

The solution included a highly energy-efficient heat recovery unit, integrated HEPA filters, and central bipolar air ionisation devices.

You can read more in the Marquis Intelligence Mini Case Studies series:
Apartment ventilation for 100 m² in New Belgrade (MI-MCS-03.3Q-25)

No. Although Marquis Intelligence often installs these systems in luxury villas and high-end residences, the company also designs solutions for flats, studio apartments, and smaller residential spaces.

Therefore, every project follows the client’s budget, needs, and expectations.

CONFIRMATION

In the blog “Residential Ventilation by Marquis Intelligence”, you can find more information on how and why Marquis Intelligence residential ventilation systems matter, regardless of size or property value.

From the Marquis Intelligence perspective, every residential space is equally important. Smaller properties can often be even more demanding. Marquis Intelligence applies the same methodology and attention to detail across all projects – whether it is a large commercial development such as Skyline Belgrade, Delta House (New Belgrade), or The Beaumont Hotel (London), or a small family flat.

Marquis Intelligence delivers both centralised and decentralised ventilation systems with heat recovery for flats and houses.

However, the best solution is not the same for every property.

First, the team analyses the size of the space and the number of rooms.
Then, it reviews the available installation options.

As a result, Marquis Intelligence proposes the most suitable technical and cost-effective solution.

In addition, the company designs every system individually.

Each solution follows the client’s real needs, preferences, construction type, and energy requirements.

CONFIRMATION

You can read more about house and apartment ventilation on the Marquis Intelligence blog:
Residential Ventilation by Marquis Intelligence.

Moreover, you can read more about the choice between plate and rotary heat recovery units in the text:
Plate or Rotary Heat Recovery Unit in Residential Central Ventilation?

Marquis Intelligence supplies and installs residential ventilation systems as turnkey solutions.

First, the team analyses the space.

Then, it selects the appropriate technology and designs the system.

After that, Marquis Intelligence procures the equipment, installs the system, sets the operating parameters, and completes commissioning.

As a result, the client receives a complete solution that is ready for use immediately after the works.

In addition, Marquis Intelligence provides maintenance and technical support after installation.

CONFIRMATION

In a private penthouse in Beogradska Street, in the very centre of Belgrade, Marquis Intelligence installed a complete ventilation system with filtration and ionisation.

The solution also included concealed ceiling elements.

Moreover, the company delivered the entire project as a turnkey solution.

During handover, the team performed measurements to verify the operating parameters.

Yes. Marquis Intelligence combines ventilation systems with a range of technologies, depending on the client’s needs.

These include different types of filters (coarse, fine, EPA, HEPA, and ULPA filters), molecular filters, UV lamps, bipolar air ionisation, and other advanced solutions. As a result, Marquis Intelligence ventilation systems deliver clean and safe air as part of one integrated approach.

CONFIRMATION

Marquis Intelligence has implemented these combined solutions across many facilities.

They include the National Assembly of the Republic of Serbia, the Clinical Centre of Vojvodina in Novi Sad, and the Institute in Sremska Kamenica, as well as smaller residential properties and a wide range of industrial and hospitality buildings.

Yes. You can integrate ventilation systems into existing properties. In practice, there are two main options: installing a central ventilation system or using a decentralised ventilation system. Marquis Intelligence can also deliver discreet solutions that do not require major construction works and fit seamlessly into already finished interiors.

CONFIRMATION

A strong example of retrofitting ventilation into an existing property, without any wider renovation, is a flat in New Belgrade. There, Marquis Intelligence installed a ventilation system with heat recovery, HEPA filters, and molecular filters, without compromising the interior design.

You can read more about this three-day installation in the Marquis Intelligence Mini Case Study:
Apartment ventilation for 100 m² in New Belgrade (MI-MCS-03.3Q-25).

Yes. Marquis Intelligence can install ventilation systems without running air ducts.

In that case, the solution uses decentralised ventilation systems.

These systems can operate with sensor-based control.

In addition, they can be installed in both new-build and existing properties.

However, the building must have a façade suitable for heat recovery units. This means the façade cannot be fully glazed. Instead, it must include wall sections where the devices can be mounted.

CONFIRMATION

Decentralised ventilation systems are generally less energy-efficient than central ventilation systems.

However, the individual heat recovery units do not take up indoor space.

At the same time, the system requires more façade openings across the building envelope.

These units usually have a lower individual capacity than central heat recovery units.

Nevertheless, multiple devices can work together in a coordinated operating mode.

As a result, they can provide the required supply of fresh air.

However, decentralised systems do not support integrated multi-stage filtration and advanced air purification in the same way as central systems.

Typically, they include only basic mechanical filters.

Yes. All ventilation systems require regular maintenance. You need to replace filters and periodically wash the heat exchanger core of the heat recovery unit.

In most cases, maintaining a decentralised ventilation system is more demanding than maintaining a central ventilation system. With a central system, you replace filters at the central heat recovery unit. However, with a decentralised system, you must replace filters on every individual unit. The same principle applies to cleaning the heat exchangers.

CONFIRMATION

For users with central ventilation systems, maintenance is much easier because the service technician only needs access to the room where the central heat recovery unit is installed. With a decentralised system, the technician usually needs to access every ventilated room in the property.

Central heat recovery ventilation systems installed by Marquis Intelligence as a turnkey solution can recover up to 93% of the heat from exhaust air. This level of heat recovery reduces heating and cooling costs, while still delivering a continuous supply of fresh air without unnecessary energy loss.

If required, Marquis Intelligence can also specify heat recovery units certified for passive houses. That depends on the client’s preferences.

CONFIRMATION

It is important to understand that installing a heat recovery unit certified for passive houses does not automatically make the building energy-efficient or classify it as a passive house.

To meet the passive house standard, a building must also comply with many other requirements defined by relevant standards and regulations.

Yes. Marquis Intelligence installs systems with digital control and the option to manage remotely via mobile apps or smart home platforms. That is the same for both central and decentralised ventilation systems.

CONFIRMATION

Most users choose remote control functionality, although they typically use the app mainly to monitor system performance. In practice, due to very low energy consumption and the high level of comfort the system provides, users rarely switch the system off.

Ventilation significantly reduces carbon dioxide (CO₂) levels, which tend to build up in spaces without controlled ventilation — especially at night — and can disrupt sleep quality. The same issue often occurs during poor weather conditions, when people keep windows closed, while CO₂ continues to accumulate due to normal breathing. A central ventilation system removes this excess CO₂ and maintains stable indoor air conditions.

In addition, a ventilation system reduces the presence of allergens, PM particles, and bacteria in the living space. As a result, it improves sleep quality and helps reduce the frequency of respiratory issues. Clean air directly supports comfort, well-being, and long-term health for everyone at home.

CONFIRMATION

When Marquis Intelligence installed its first central heat recovery ventilation system in Krunska Street, in central Belgrade, the investor, who was also the end user, said at the very first contractor meeting:
“The smartest thing I did in this flat is the installation of ventilation. I sleep as if I’m by the sea, and I wake up rested after only five hours of sleep. I actually get proper sleep.”

Marquis Intelligence designs ventilation systems in line with applicable European and German standards. In particular, the following are used:

• DIN 1946-6 – the standard for the ventilation of residential and similar buildings, with clearly defined methods for calculating the required ventilation rates.
• EN 16798 – covering indoor environmental parameters, including ventilation, energy efficiency, and air quality.

The team does not perform calculations manually. Instead, Marquis Intelligence uses a specialised software tool that operates through a central server in Germany and delivers a high level of accuracy.
Only qualified professionals prepare the designs — engineers who have completed relevant training and hold Licence 330, in line with the laws of the Republic of Serbia and current technical regulations.

CONFIRMATION

Marquis Intelligence does not rely on generic calculations. Instead, the team performs object-specific calculations based on real data for each project, including the architectural and technical characteristics of the space.

Yes. Marquis Intelligence delivers the full ventilation implementation process — from design, supply, and installation, to commissioning and verification of the designed performance parameters.

A licensed engineer supervises all works through formal technical oversight and holds the appropriate licence for this type of installation — Licence No. 440, in line with the laws of the Republic of Serbia and applicable technical regulations. This approach ensures compliance with legal obligations, technical standards, and the warranties provided to the client.

In addition, the Marquis Intelligence team has extensive experience coordinating ventilation works with other on-site construction and refurbishment activities to achieve maximum system functionality and efficiency.

CONFIRMATION

Among other examples, in almost all residential ventilation projects, Marquis Intelligence has taken responsibility for all phases of system delivery – from design and implementation to engineering supervision during installation works for ventilation and air purification systems.

No. A kitchen hood is a local extraction system designed to remove smoke, steam, and odours directly above the cooker.
Whole-home ventilation does not replace a hood. However, it supports better overall air quality in the kitchen and throughout the entire home.
In professional kitchens, air treatment from canopy hoods requires dedicated multi-stage systems.

CONFIRMATION

Marquis Intelligence insists that the kitchen area must have an independent extraction and air purification system for air loaded with grease vapours, particles, fumes, and cooking odours.

You can learn why this is essential in the Marquis Intelligence blog post:
8 Facts: Why Kitchen Ventilation Matters for Health..

No. When a central ventilation system is installed in an existing property, the bathrooms and toilets become part of the designed exhaust ventilation system.

Therefore, the existing local bathroom exhaust fans are no longer necessary.

However, in most cases, they do not interfere with the operation of the central ventilation system. As a result, they can remain in place and continue to operate.

The central ventilation system provides continuous removal of humid and polluted air from bathrooms, toilets, and other rooms.

At the same time, it ensures stable and controlled airflow throughout the building.

Occasional use of the existing bathroom exhaust fan does not negatively affect the operation of the central ventilation system.

For decentralised ventilation systems, bathroom exhaust fans are usually recommended.

They help remove moisture and odours more efficiently.

CONFIRMATION

In several apartment renovation projects, Marquis Intelligence installed central heat recovery ventilation systems while the existing bathroom exhaust fans remained in operation.

Their occasional use is comparable to using a kitchen extractor hood.

Therefore, local removal of moisture or odours does not interfere with the operation of the central ventilation system.

In residential central ventilation systems, the two most commonly used types of heat recovery units are plate heat exchangers and rotary heat exchangers. Both systems have clearly defined technical advantages and limitations.

Plate heat exchangers provide complete physical separation of airflows, while rotary systems involve a small degree of mixing between exhaust and supply air.

Moisture transfer in rotary heat exchangers depends on the rotor type and operating conditions of the system. In standard rotors, it mainly occurs under larger temperature differences or in enthalpy versions.

The choice between these two types does not represent a universally “better” or “worse” solution. It depends on multiple design parameters, such as required airflow capacity, available installation space, acoustic requirements of the building, filtration level, and overall energy efficiency of the system.

Marquis Intelligence always approaches the selection of a heat recovery unit as the result of a technical analysis of the building and project priorities, rather than as a predefined technological preference.

CONFIRMATION

detailed comparison of plate and rotary heat recovery units is explained in the Marquis Intelligence technical article:
Plate or Rotary Heat Recovery Unit in Residential Central Ventilation?

Yes, it is still necessary. A split-system air conditioner does not provide ventilation for the space.

Air conditioning systems are primarily designed to cool or heat the air already present indoors, but they do not supply fresh outdoor air or remove pollutants generated inside enclosed spaces.

During occupancy, the following typically occur indoors:

• increased CO₂ concentration,
• development of unpleasant odors,
• increased humidity levels,
• accumulation of particles and other airborne pollutants.

Ventilation systems serve a different purpose than air conditioners – they provide a controlled supply of fresh outdoor air and removal of polluted indoor air.

In modern buildings, air conditioning systems and ventilation systems operate together, but they perform different roles in ensuring a healthy and comfortable indoor environment.

CONFIRMATION

In one apartment in Belgrade where Marquis Intelligence designed and installed a central ventilation system, the space already had heating and cooling systems, as well as air purifiers, before the installation. Despite this, indoor air quality remained poor. Elevated concentrations of carbon dioxide (CO₂) and nitrogen oxides (NOx) were recorded.

No. Ventilation cannot replace heating and cooling systems.

The primary function of ventilation is to provide fresh air supply and remove polluted indoor air, while heating and cooling systems are designed to control indoor temperature.

In modern buildings, ventilation systems often include heat recovery units, which allow partial recovery of heat from exhaust air and thereby reduce energy losses.

However, such systems cannot fully replace heating or cooling systems. Instead, they serve as a complementary solution that contributes to energy efficiency and improved indoor air quality.

CONFIRMATION

In Marquis Intelligence residential ventilation systems, the heat capacity of air and the airflow rates defined according to DIN 1946-6 are not sufficient to heat or cool a building exclusively through ventilation.

Even when the supplied air is additionally heated or cooled, the ventilation system itself is not designed to assume the role of a dedicated heating or air conditioning system.

Yes. Ventilation and clean air represent added value in the real estate market, especially in luxury apartments and villas, as well as in commercial properties.

Buyers are becoming increasingly aware of the importance of air quality, particularly in urban environments, which directly affects property value.

CONFIRMATION

According to The Wall Street Journal article “The Newest Must-Have Home Amenity for the Rich: Purified Air”,  the value of a luxury home in San Francisco increased by more than 10% after the installation of an air purification and ventilation system.