Cases - DUKA Ventilation https://dukaventilation.com/ Find the right ventilation solution for your home Tue, 02 Jun 2026 11:49:29 +0000 en-GB hourly 1 https://wordpress.org/?v=7.1 https://dukaventilation.com/wp-content/uploads/2025/11/android-chrome-192x192-1-100x100.png Cases - DUKA Ventilation https://dukaventilation.com/ 32 32 Study of radon reduction using DUKA One https://dukaventilation.com/investigation-of-radon-reduction-with-duka-one/ Mon, 01 Jun 2026 12:50:14 +0000 https://dukaventilation.dk/?p=162465

Study of radon reduction through the use of DUKA One in a detached house with a basement

In a detached house with a basement in Silkeborg, Denmark, radon measurements were carried out. The basement was used for several living purposes, including an office, a TV and games room, and a guest room. Although the basement was not used as a permanent bedroom, residents regularly spent extended periods in the rooms above.

After several years of consideration, the homeowner opted to have a radon measurement carried out. The measurement was conducted over a period of two months and showed an average radon level of 800 Bq/m³. This level is significantly above the 100 Bq/m³ that Danish authorities recommend as the upper level for radon in indoor air.

The investigation

The aim of the study was to determine whether the installation of decentralised ventilation could help to reduce radon levels in the basement. The study was carried out by monitoring changes in radon concentration following the installation of two DUKA One and two Pro 50 ventilation units.

Solution selection

Before the installation, various options for reducing radon levels were considered. One of the initial measures was increased manual ventilation, particularly during periods when the family was at home. However, this solution proved difficult to maintain in practice, partly due to the cold and increased heating consumption during the autumn.

Against this background, a more permanent solution was sought. In consultation with DUKA and drawing on knowledge of existing ventilation products, the DUKA One Pro 50 was assessed as a possible solution. The solution was chosen, among other things, because it could be installed without major disruption to the entire property, and because it could simultaneously ensure continuous air exchange in the basement.

Installation and measurement method

Two DUKA One ventilation units were installed in the basement. The installation was carried out by a local electrical contractor. As part of the project, the OBH Group, a consulting engineering firm with expertise in indoor climate, was involved in the measurement process.

Following installation, the radon level was measured with three digital radon meters placed in different locations in the basement. The measurements were initiated on the same day as the installation and continued throughout the winter. The preliminary results were used to assess the development of radon concentration at different ventilation levels.

Results

The initial measurements showed a significant drop in radon levels following the installation of the ventilation units. As early as the day after installation, a reduction of 81 % was recorded whilst the units were operating at ventilation level 1.

In the subsequent period, the radon level was measured at three different speed settings:

Radon meters
Reduction of Radon Level at Speed Stage 1
Reduction of Radon Level Speed Step 2
Reduction of Radon Level on Speed Step 3
Measure 1
 80,3%
87,3%
90,3%
Measurement 2
74,9%
88,2%
91,3%
Measure 3
73,9%
87,9%
92,5%
Average reduction of Radon level
76,4%
87,8%
91,4%

At ventilation level 1, an average reduction of 76.4 % was recorded over six days. At ventilation level 2, which was used for seven days, the average reduction was 87.8 %. At ventilation level 3, which was used for six days, the average reduction was 91.4 %.

The results indicate that the measured radon level in the basement fell significantly after the installation of the ventilation units. Furthermore, a correlation was observed between a higher ventilation level and a greater average reduction in the radon level.

Supplementary observations

In addition to the measured reductions in radon levels, residents experienced an improvement in air quality in the basement. According to the homeowner, the air in the living spaces felt fresher, even when the doors had been closed for extended periods.

This observation is subjective and should be seen as a supplement to the measured raw data.

Assessment

Preliminary measurements show that the installation of two DUKA One ventilation units in this particular basement was associated with a significant reduction in radon levels. The average reduction ranged from 76.4 % to 91.4 %, depending on the ventilation level.

It should be noted, however, that the study is based on one specific property and a limited measurement period. The results can therefore not be directly generalised to all buildings with elevated radon levels. The effect of ventilation can depend on several factors, including the building's construction, soil conditions, leaks in the foundation, air exchange rate, location of ventilation units, and usage patterns.

Further measurements over a longer period and in more types of housing will be able to provide a more nuanced picture of in which situations decentralised ventilation can be a relevant method for reducing radon in the indoor environment.

Radon. A brief overview

Radon is a naturally occurring radioactive gas that is formed underground. The gas can penetrate buildings through cracks and leaks in foundations, floor constructions, and cellar walls. As radon can neither be seen, smelled, nor tasted, elevated levels can only be detected through measurement.

The highest radon concentrations typically occur in basements and ground floors, as these parts of the building are closest to the ground. According to nationwide surveys, a significant number of Danish homes are estimated to have radon levels above the authorities' recommended limit.

Danish authorities recommend that the radon content in indoor environments does not exceed 100 Bq/m³. For new construction, the building regulations require that this level is not exceeded. For existing buildings, it is a recommendation.

Radon is associated with an increased risk of lung cancer, particularly with prolonged exposure. The risk is significantly higher for smokers than for never-smokers. According to the World Health Organisation (WHO), radon is the second-largest contributing cause of lung cancer after active smoking.

Sources: Danish Health Authority and Danish Technological Institute

Do you live in an area with high radon levels? Check the map here: DinGeo Radon Map

About DUKA One

DUKA One is a decentralised single-room ventilation solution with heat recovery. The unit works by alternately extracting stale indoor air and supplying fresh outdoor air. During this process, some of the heat from the extracted air is transferred to the supply air via a ceramic heat exchanger.

The solution does not require a traditional duct system throughout the home and can therefore be installed locally in the rooms where ventilation is desired. In this study, the solution was used as a possible measure to reduce radon levels in a basement with elevated readings.

Conclusion

In the property under investigation, a significant reduction in radon levels was recorded following the installation of two DUKA One ventilation units. Preliminary measurements showed average reductions of between 76.4% and 91.4%, depending on the ventilation level.

The results indicate that decentralised ventilation had a positive effect on radon levels in the basement in this case. At the same time, the conclusion should be considered case-specific, as the effect can vary from one home to another. In cases of elevated radon levels, it is always recommended to have specific measurements taken and to assess possible solutions based on the building's conditions.

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]]> 162465 Get the best out of your basement https://dukaventilation.com/get-the-best-out-of-your-cellar/ Mon, 01 Dec 2025 08:38:17 +0000 https://dukaventilation.dk/?p=161370

Black Edition

Get the basement of your dreams

Live your dreams in a basement with a healthy indoor climate

Utilise your basement square metres

A healthy indoor climate in the basement is essential if you want to utilise the full potential of your home. Many basements sit unused or only serve as storage rooms because humidity, cold and poor ventilation make them uncomfortable to spend time in. But with the right indoor climate, basement square metres can be transformed from wasted space to valuable square metres.

When moisture and bad air are removed and ventilation is optimised, you create an environment that is both healthy and comfortable. This means fewer mould problems, better air quality and an overall healthier home to live in.

At the same time, the value of the property increases significantly when the basement becomes an area you can actually use. A healthy indoor climate opens the door to new possibilities: extra living space, home office, hobby room, fitness centre, guest room or simply dry, comfortable storage space. The square metres take on a whole new function and buyers see great potential in a basement that is dry, ventilated and in good condition.

A good indoor climate in the basement is an investment that improves the health of your home, provides more usable space and creates economic value.

DUKA One

Create a healthy indoor climate in the basement - easily, efficiently and without major renovations

Ensuring a healthy indoor climate in the basement can quickly seem like an extensive and unmanageable project. Moisture, bad air and a stagnant indoor climate make the basement a place to avoid. But with DUKA One, With an efficient one-room ventilation solution, it becomes much easier to create a comfortable and healthy basement environment.

The DUKA One is mounted directly in the outer wall and requires minimal installation. The unit automatically switches every 70 seconds between sucking out stale, moist air and blowing in fresh, filtered outdoor air. This continuous air exchange gives the basement the breath of fresh air it often lacks - creating an indoor climate that is both healthier and more stable.

When air is constantly in motion, it is much harder for moisture to stick to walls, floors, furniture and stored items. This significantly reduces the risk of moisture damage, mould and mildew. At the same time, you avoid the typical “basement odour” that often settles in clothes, furniture, cardboard boxes and other stored items. With fresh air, the basement becomes a usable and comfortable space again.

A healthy basement indoor climate allows you to utilise the full potential of your home. Once the humidity is under control, the basement square metres can suddenly be used for hobby rooms, storage without worries or as extra living space - and the value of the home increases accordingly.

With DUKA One you get a simple, energy-friendly and efficient solution that gives your basement new life. An investment that both improves the health of your home and increases the possibilities of using the basement actively in everyday life.

Read much more about DUKA One here
Black Edition

When it doesn't always have to be white

Many choose white as the standard colour for ventilation solutions, but with Black Edition you get the benefits of advanced ventilation and Aesthetic minimalism. The black colour makes the unit more neutral - especially in modern, dark or stylish interiors - and prevents the fan from dominating the room. The Black Edition fits perfectly in rooms with dark walls, woodwork, concrete, concrete ceiling or industrial design, but works equally well in classic homes where discretion is a plus.

At the same time, you get all the functionality of the DUKA One: heat recovery, energy-efficient operation, low noise level, easy installation and flexible supply air settings. A black ventilation screen makes it more attractive to place the unit in living rooms, bedrooms or basements - yes, even in basements where you want a more “finished” and residential feel.

DUKA One Pro 50 S Black EditionDUKA One Pro 50 S Wi-Fi Black Edition

Unleash the good indoor climate

Fresh air, good tones and the feeling of freshness

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]]> 161370 New life for a damp basement https://dukaventilation.com/new-life-for-a-damp-basement/ Fri, 27 Jun 2025 06:44:59 +0000 https://dukaventilation.dk/?p=157552
Basement

New life for a damp basement

Trine and Mikkel live in a master builder's villa from 1935 with a large basement. They would like to use the basement for storage and creative space. Unfortunately, they have a very familiar problem in their basement - moisture. And moisture is not the only challenge the basement presents. Water has found its way into the basement several times and they have also had mould.

The basement has therefore undergone a major transformation with mould control, new windows, installation of a heat pump, new tiled floors, treatment of walls with breathable materials.

Although they have done many things to make the basement usable, it is still very damp. One of the ways they experience this is that the textiles Trine has stored in the basement for their creative projects feel damp and clammy.

“The basement is now the place in the house with the best indoor climate” - Mikkel

Simple and easy installation

So the next step in their ‘Get the basement back’ project is to install ventilation. Trine and Mikkel have therefore chosen to install 3 DUKA One Pro 50 S Wi-Fi units with a brick red outer screen that matches the house. 

A diamond drill was responsible for drilling the hole. Mikkel did the rest of the installation himself.

A completely different basement

After installing DUKA One in their basement, Trine and Mikkel can feel a clear difference and say that everything just works. 

The basement is clearly the room in the house with the most fresh air, and one of the ways we can feel it is that the textiles that Trine has stored in the basement are no longer damp. And in general, they are amazed at how well they work.

We kind of want to just install it in the whole cabin now - Quote Mikkel

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]]> 157552 DUKA One provides good indoor climate in Fillip's Tiny House https://dukaventilation.com/duka-one-provides-good-indoor-climate-in-fillips-tiny-house/ Thu, 26 Jun 2025 12:00:36 +0000 https://dukaventilation.dk/?p=157540
Tinyhouse

A new and well-insulated tinyhouse meant that moisture could not escape.

“We solve that with DUKA One” - Filip

Filip and Tina's new tinyhouse has a cosy kitchen, a small living room, a toilet and a bedroom, which together create a beautiful and compact home. This will be the couple's new home after moving out of their apartment in Aarhus. But even before their tinyhouse was finished, Filip could quickly see that dew was gathering on the windowsills and that the air was very dense.

Why should it be the DUKA One S4 Plus Wi-Fi model?
The advantage of choosing a smaller model like the DUKA One S4 Plus or DUKA One Pro 25 S for a tinyhouse or something like a holiday home is that they have a core and motor of just 165 mm, so it can fit in thinner walls.

Easy, fast and high quality

The solution to the high humidity can easily be solved by opening windows, “but the idea of insulating well was not that all the heat should just escape through an open window,” says Filip. Therefore, the solution was DUKA One, which is easy, fast and made in high quality.
“It's nice when you work with quality products,” he says as he prepares the inner screen for installation.

Filip talks about several benefits of DUKA One:

  • It works and is easy to install and operate
  • A scalable solution so you can easily add extra DUKA One units later if needed.
  • Quick and easy without breaking the budget.

No possibility of complicated pipework

As this tinyhouse has a flat roof, there is no room for pipework, so a solution that only requires a hole in the outer wall is needed. This means installation is straightforward and hassle-free. A wet room DUKA Ventilator has also been added to the toilet so that the wet room in the home does not give the neighbouring rooms high moisture levels.

Wi-Fi

Weekly programme and Wi-Fi is a must“

There was no doubt that the Wi-Fi model was the right DUKA One to go with as it offered several advantages. With the Wi-Fi version, it's easy to connect multiple devices wirelessly, check if they are running in the DUKA Smart App and create a weekly programme for the devices.

The weekly programme in particular is a hit, as it doesn't matter in a compact home when the humidity level is high. Therefore, it makes sense to be able to set DUKA One to change speed depending on whether someone is home or empty.

Investment

Consider investing in a DUKA One solution

We recommend DUKA One, a ventilation solution that ventilates the room 24 hours a day. For 70 seconds, the unit sucks out stale and humid air, storing heat in the unit's ceramic core. After 70 seconds, the system's motor reverses and blows in fresh air that is heated by the ceramic core. This constantly changes the air, reducing particles and moisture, while saving on heating bills as the heat is recycled. DUKA One is mounted directly in the outer wall and can be installed wherever there is a need for ventilation.

Find the right DUKA One here

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]]> 157540 DUKA One provides a good indoor climate at Bramming gymnastics & sports secondary school https://dukaventilation.com/duka-one-provides-a-good-indoor-climate-at-bramming-gymnastik-idraetsefterskole/ Thu, 26 Jun 2025 10:43:06 +0000 https://dukaventilation.dk/?p=157533
Bramming gymnastics & sports after school

DUKA One provides a good indoor climate at Bramming gymnastics & sports secondary school

“We experience less humidity and it smells better in the rooms” - Otto, Caretaker

As part of an energy renovation at Bramming gymnastics & sports secondary school, they faced a ventilation challenge. For a long time it has been okay with a fresh air vent, but after new and more insulating windows were installed in the student rooms, it can create quite a haze in the student rooms, especially in a 3-man room with three active boys.

Big savings by setting up DUKA One

After Otto, the caretaker at Bramming gymnastics & sports secondary school, heard about DUKA One, he tested it in a single student room. After some time, he and the management quickly came to several conclusions:

  • It works and was easy to install and operate
  • It would cost less than a third to set up, compared to a larger unit that would have to be installed in the attic.

Avoid working under an asbestos roof

Installing a classic ventilation unit with heat recovery in the attic would require more work. Complicated pipework and insulation would take time and effort, which is why it made even more sense to install the popular 1-room heat recovery unit, DUKA One, in each room.
DUKA One only requires a hole in the outer wall and power to the indoor unit. This made it quick and easy, and didn't require a single trip to the attic.

It made sense to choose the Wi-Fi model

There was no doubt that the Wi-Fi model was the right DUKA One to go with as it offered several advantages. With the Wi-Fi version, it's easy to connect multiple devices wirelessly, check if they are running in the DUKA Smart App and create a weekly programme for the devices.

Consider investing in a DUKA One solution

We recommend DUKA One, a ventilation solution that ventilates the room 24 hours a day. For 70 seconds, the unit sucks out stale and humid air, storing heat in the unit's ceramic core. After 70 seconds, the system's motor reverses and blows in fresh air that is heated by the ceramic core. This constantly changes the air, reducing particles and moisture, while saving on heating bills as the heat is recycled. DUKA One is mounted directly in the outer wall and can be installed wherever there is a need for ventilation.

Find the right DUKA One here

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]]> 157533 DUKA One ensures a good indoor climate in Residential Building of the Year 2019 https://dukaventilation.com/duka-one-ensures-a-good-indoor-climate-in-residential-buildings-of-the-year-2019/ Tue, 17 Jun 2025 06:51:53 +0000 https://dukaventilation.dk/?p=157133
DUKA One

DUKA One brings a breath of fresh air in the Residential Construction of the Year

Venlig Bolig Plus in Frederiksberg has won the award for Housing Construction of the Year 2019. The building consists of 3 clusters of apartments where either 2 students or 2 refugees live together in an apartment. The students will act as mentors for the refugees living in the Friendly Homes.

Each apartment is 33 square metres and consists of a shared kitchen/living room and bathroom as well as two small individual rooms. The building is designed according to the concept of ‘small living’, which places high demands on the utilisation of the square metres. DUKA One is a brilliant solution here, as it does not require pipework but is installed in the outer wall, freeing up important space in the apartments. In the future, apartment heating costs are also kept down as DUKA One units utilise the heat that is already in the apartments. DUKA One ventilates constantly in cycles of 70 seconds. First, used air is extracted for 70 seconds and the heat is stored in the ceramic core. After 70 seconds, the unit reverses direction and blows in fresh air that is heated by the ceramic core.

In the apartments, a DUKA One S6 is installed in each room and a DUKA One S6B in the bathroom. DUKA One S6B is specially developed for wet rooms, where the unit's two motors alternately suck out and blow in for 70 seconds, after which the direction is changed. During extraction, the heat is recycled. The two motors ensure that an even pressure is maintained in the bathroom. If moisture is present, both motors will extract air until the moisture level is below the set limit again.

The structure of the building encourages a sense of community with roof terraces in each cluster and common rooms on the ground floor. These common areas are also ventilated with DUKA One units.

The clusters are constructed from prefabricated modules that can be easily prepared for the DUKA One units at the factory, where the holes for the ceramic core are pre-drilled, making final assembly on site easy.

Housing in Copenhagen - and especially in Frederiksberg - is often expensive, so it has been important to keep construction costs and thus also rents down. The modular construction and DUKA One units have helped to ensure this. Here, a resident has to pay just under DKK 3,000 in rent per month.

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]]> 157133 DUKA One has eliminated the odour in my basement https://dukaventilation.com/duka-one-has-removed-the-odour-in-my-basement/ Fri, 13 Jun 2025 08:20:55 +0000 https://dukaventilation.dk/?p=157012

DUKA One has eliminated the odour in my basement

Despite extensive insulation and renovation of his basement, Jesper from Viborg was still experiencing the unpleasant odour in his basement. He realised that some form of ventilation was needed and after talking to a ventilation professional, Jesper decided to get a DUKA One for the job.

We renovated the basement with a focus on good insulation, but it still had a bit of a basement odour, so we thought it probably needed some form of ventilation. I spoke to a professional who told me about DUKA One and what it can do for basement odours and the indoor climate in the basement.

The difference is easy to spot

It didn't take long for Jesper and the whole family to notice how their new DUKA One ventilated their basement with great success.

We've had it for 4 years and we can really feel the improvement. My family has noticed a big difference in the basement smell and odours.

Poor air quality in basements is often caused by lack of ventilation and can lead to dampness, mould and bad odours. This creates an unhealthy indoor climate that can affect health and the building. Good ventilation prevents problems and ensures a dry, healthy and comfortable basement environment.

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]]> 157012 The difference was clear - the solution was simple https://dukaventilation.com/the-difference-was-clear-the-solution-was-simple/ Fri, 16 May 2025 08:19:35 +0000 https://dukaventilation.dk/?p=156509 After designing my ideal week, I had a much clearer idea of how to create a framework for my week that would empower me to feel more focused by theming days of the week, and even parts of the day. I spent nearly a year turning down every new project (and even getting rid of old ones) so that I could reduce my workload, build in more margin, and create what is now Digital Strategy School. It takes time to build margin into your schedule.

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