FREQUENTLY ASKED QUESTIONS

FAQ about our products and dehumidification.

Did you know that the average relative humidity in Sweden is 85% in January and 75% in July, according to SMHI? The limit for general corrosion (rust) is 60% relative humidity.

Therefore, air ventilated into buildings should either be heated or dehumidified!

Webinar: how moisture works!

Moisture challenges - frequently asked questions on moisture management

Watch the video on how to read a Mollier diagram.

The energy efficiency of a dehumidifier is measured by the energy required to extract one kilogram of water from the air, in the climate in which it will operate.

On product sheets, you can usually read out the dehumidifier's capacity at different temperatures and humidity levels, stated in relative humidity [%RH]. The capacity is stated in kilograms of water per hour. Multiply this figure by the dehumidifier's power consumption, and you get the cost of dehumidification!

It is important to use the correct temperature and humidity level when making comparisons!
Especially if you also want to save energy by lowering the temperature in the room.

Good humidity levels in most premises are below 60%RH. This avoids mold and corrosion. All older technologies require more energy at lower temperatures. Airwatergreen hot condensation technology is the only one that is completely independent of the climate in which the dehumidifier works.
With the FLEX series, it costs only 2 KWh to extract 1 kilogram of water from the air according to tests by the National Testing Institute, with the REX series about 1.5 KWh per kilogram of water.

See diagram by Statens Provningsanstalt (SP) (RISE)
If you want help with calculating moisture or life cycle calculation for the next dehumidification purchase, email us at info@airwatergreen.com

The important factor for corrosion to occur is the dew point on the pipe. If the pipe is colder than the air in the room, the dew point is lower at/on the pipe and moisture in the air will start to form on the pipe with corrosion as a result. Just like a soda can on a hot summer day.

We can calculate the dew point and configure the dehumidifier to use an external sensor that measures just the temperature of the pipe and in that way control the dehumidifier to work to keep the right humidity level to avoid condensation.

Dew point diagram:

Yes, we can do a moisture investigation using sensors. We place these moisture sensors in selected positions for a couple of weeks and based on the data from these sensors we can present an assessment of the moisture levels over time.

Based on this data, we can advise on how to proceed depending on the type of moisture challenges using a calculation methodology we have developed.

We have the equipment and can help you with the installation and, if necessary, install a drainage pump to take the water out of the space if it is underground and there is no floor drain or sewer.

No, you can lower the temperature. Our technology is as effective in cold air as in hot!

Reducing heating has proven very successful in churches and buildings that are not always used. Lower the temperature in the building and our FLEX or REX will keep the humidity at the right level. This can save a lot of energy both from lower heating costs and from a more efficient dehumidifier.

As an example, a church building can reduce its energy consumption by over 80%, giving a payback period on the investment of just over 1 year.

Below is a description in a Mollier diagram of what happens when the temperature changes without removing water from the air.

  1. The temperature is lowered from 20C to 11C (blue arrow) which means that the relative humidity level goes up from 50%RH to almost 100%RH. If nothing is done about this, corrosion and mold formation will occur.
  2. Reducing water from the air (brown arrow) at the same temperature results in a reduction back to 50%RH. Less than 5g of water per m3 of air needs to be removed.

Dehumidification of materials can be divided into three phases.

  1. Water is sucked capillary from inside the material to the surface.
  2. Transport occurs as capillary transport in the liquid phase in the small pores and in the vapor phase (diffusion) in the larger pores.
  3. Transport takes place in the vapor phase only. The speed is controlled by the difference in vapor content between the material and the surrounding air.

Step 1 is highly dependent on the type of material to be dehumidified. What can usually be influenced most is step 3, i.e. to ensure that the moisture leaves the surface of the material and goes into the air. If you can heat the material that the moisture is in, the process is accelerated.

The easiest way is usually to make sure that the air is kept dry at all times and preferably at a low relative humidity (RH) level. This results in increased vapor content difference and faster dehydration!

See the graph on the right showing the differences in vapor pressure at different RH when the air and material are at the same temperature.

In other words, lowering the RH of the air to 40% speeds up the drying process because the difference in vapor pressure increases (left axis). This results in faster drying!

Heating of the air

The graph on the right shows what happens if you only heat the air. Then the vapor pressure difference can become negative at slightly higher relative humidity levels.
This leads to the moisture in the air condensing on the wall instead.

So it can lead to humidification instead of dehumidification if you are not careful!

Typical questions about dehumidification

Hot condensation is a patented technology that first traps moisture in an adsorbent (desiccant) and then dries it out in a closed hot condensation process.

Water and dry air are supplied. No connections except for water drainage are needed, which makes the installation easy and all supplied energy stays in the room and is not ventilated out.

With Airwatergreen's technology, the dehumidifier works equally efficiently in all climates regardless of temperature and can therefore dehumidify even in sub-zero temperatures. How hot condensation works as a method is described in detail in this report Modeling a novel sorption dehumidification method - written by Per D

Keeping the air warm can hardly be considered a dehumidification method as no moisture is taken out of the air.

However, heating the air will lower the relative humidity (Rh) level because warm air can "hold" more humidity than cold air. No water is removed from the building's air, which means that heating must be kept on forever to avoid excessive relative humidity.

A study conducted at Uppsala University shows that it is about 5 times more energy consuming to maintain the same relative humidity using heating versus using dehumidification. If you want to read the study, it is available for download here.

Ventilation should not be considered as dehumidification as no water is removed from the air. The method is entirely dependent on the outdoor climate and how the temperature is outside in relation to the temperature in the space that has moisture challenges. Perhaps you are bringing more humidity into the building instead of removing it?

Ventilation is used quite often because it is considered a cheap and easy solution. But ventilation can create more problems than it solves. A typical situation we often see is when the ventilation lets warm moist air into the cool crawl space during summer - not a suitable method!

Water droplets are created on a cold surface - this is common knowledge. It is due to the fact that cold air cannot hold the same amount of moisture as warm air. This fact can be used in dehumidification because it actually takes the water out of the air. But at the same time, this phenomenon is also the reason why corrosion and mold occur in buildings and structures!

To use cold condensation as a dehumidification method, the air must be reheated after condensation. Otherwise, the relative humidity will remain at the same high level.

This means that this method can only be used at certain temperatures to avoid ice build-up at the cold surface.

Sorption dehumidification is considered to be the modern dehumidification method created in the 1950s in Sweden to dehumidify under Swedish climate conditions. Over the years, this method has been used in many installations.

The method involves trapping the moisture in the air in a slowly rotating wheel and drying the wheel with hot air in step two. The hot air then traps the moisture again, which is then typically led out through a hole in the wall.

Installation can easily become costly depending on how to exhaust the air and energy is lost through the hole in the wall.

Do you have any questions?

Contact us

Questions about the products – FLEX, REX, BLACKBOX, and NEXT

With the new Temp Guard feature in Flex, you can ensure that the space stays frost-free with the built-in heater as a heat source.

Read more about Temp Guard here .

To be absolutely sure of our case, we had the Swedish National Testing Institute (now RISE) test our dehumidifier and compare it with a traditional sorption dehumidifier.

The results of that test show that our dehumidifiers use half as much energy to dehumidify the same amount of water.

Want to read the full test? Click here to read it.

The water taken out of the air is supplied from the outlet on the side of the dehumidifier. A hose can be easily connected so that the water can be delivered to a drain or a tank.

If no drain is available, there are specially designed containers available. A stand-alone model and a container that doubles as a trolley on wheels to easily move FLEX if needed.

The FLEX tilts to create self-draining. The water flows out of the machine without the need for a pump. This reduces energy consumption and minimizes the number of moving parts.

If the green light changes from steady to flashing, the dehumidifier needs service.

There are instructions in the manual under chapter 6 - Service. Or contact our support at support@airwatergreen.com.

We recommend replacing the granules once a year to maintain the full capacity of the dehumidifier. Suitable granules are included in our Filter Kit. This is included as a delivery in our Service agreement or you can order it directly from us.

Yes, absolutely.

The granules you need for replacement are supplied in a package called a Filter Kit. You can order Filter Kits from us. Instructions are provided in the manual (available for download fromthe FLEX and REX download page).
Or visit our YouTube channel and watch the video on how to refill the granules yourself.

Dehumidification of materials can be divided into three phases.

  1. Water is sucked capillary from inside the material to the surface.
  2. Transport occurs as capillary transport in the liquid phase in the small pores and in the vapor phase (diffusion) in the larger pores.
  3. Transport takes place in the vapor phase only. The speed is controlled by the difference in vapor content between the material and the surrounding air.

Step 1 is highly dependent on the type of material to be dehumidified. What can usually be influenced most is step 3, i.e. to ensure that the moisture leaves the surface of the material and goes into the air. If you can heat the material that the moisture is in, the process is accelerated.

The easiest way is usually to make sure that the air is kept dry at all times and preferably at a low relative humidity (RH) level. This results in increased vapor content difference and faster dehydration!

See the graph on the right showing the differences in vapor pressure at different RH when the air and material are at the same temperature.

In other words, lowering the RH of the air to 40% speeds up the drying process because the difference in vapor pressure increases (left axis). This results in faster drying!

Heating of the air

The graph on the right shows what happens if you only heat the air. Then the vapor pressure difference can become negative at slightly higher relative humidity levels.
This leads to the moisture in the air condensing on the wall instead.

So it can lead to humidification instead of dehumidification if you are not careful!

The activated carbon is easily replaced when it is no longer able to absorb hydrogen sulfide. Regular replacement is included as part of the service agreement.
Airwatergreen Blackbox Filter Kit Activated carbon contains enough for one Blackbox.

NEXT consists of two modules, of which only the collector itself is active during most of the operating time. During collection, only an air fan and a pump for the drying agent consume energy.

Regeneration is only started when needed - and then the energy consumption is independent of ambient air temperature and humidity.

Unlike traditional condensation technology, NEXT maintains NEXT efficiency even at low temperatures. NEXT is optimized to deliver good performance at temperatures (2–12°C) typical in the food industry and cold storage.
(Of course, it still works perfectly well at normal room temperature).

The unique thing about AWG's technology (CVP = Controlled vapor pressure) is that it works perfectly as a completely independent installation. You need a 32A fuse and access to a suitable drain. Nothing more!

AWG offers different levels of service agreements. Normally we count on an annual service performed by AWG personnel. In dirty environments, the external air filter may need to be changed frequently - this is easily done by the customer's own staff in a few minutes.

NEXT is based on a modern, powerful PLC that can also be upgraded remotely if necessary. We offer full connectivity to AWG's cloud service, which facilitates both monitoring and preventive maintenance. External sensors can easily be connected to optimize climate control.

AWG has extensive experience in deliveries to both the water and food industries with the special requirements for IT security that exist in those industries.