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About humidity

Typical questions about humidity

The air in the room is dry but I still have corrosion - why?

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

We can calculate the dew point and configure the dehumidifier to use sensors and operate to keep the right humidity level to avoid corrosion.


Dew point diagram

The room is humid but I do not know what the level of the humidity is.Can you help me?

Yes, we can do a humidity investigation using sensors. We place these humidity sensors in selected positions for a couple of week and can based on the data from these sensors present the humidity levels.

Based on this data we can give our advice for how to proceed depending on the type of humidity challenges using calculation methodology that we have established.


I need to bring the water out of the underground chamber?

We have the equipment and can help you with the installation and install a drainage pump that takes the water out of the chamber.

Do I need to keep warming the room?

No you can lower the temperature. Our technology is just as efficient in cold air as in warm.

This has proven very successful in Churches and cultural buildings not always in use. No unnecessary heating is needed and our FLEX and REX keeps the humidity at just the right level. Saving both from lower heating costs and from an efficient dehumidifier.

Our Products

Flex, Rex and Blackbox

What do I do with the water from the FLEX that is taken out of the air?

The water that is taken out of the air is delivered from the tap at the end of the dehumidifier. A hose can be connected to the tap so that the water can be delivered to a drain. 

If no drain is available a specifically designed container is available. This container will also act as a wagon on wheels to move the FLEX easily around if needed.

Why is the FLEX slightly tilted?

The FLEX is tilted to make the water pour out of the machine without having to use any unnecessary pump. This reduces energy consumption and reduce the number of moving parts.

There is a green lamp flashing at the panel of the FLEX. What should I do?

If the green lamp changes from a steady light to flashing the unit needs service.

There is guidance in thein the manual under chapter 6 Service. Or contact our support at support@airwatergreen.com.

I have a control system today. Can I connect the dehumidifier to it?

Yes, both the FLEX and the REX model Integrate is prepared for communication via Modbus to any standard control or monitoring system.

The model Cloud can be connected via WIFI. Status from the dehumidifier is made available but also data from sensors registering humidity (Rh), temperature etc is available.

How often do recommend to replace the granulate?

We recommend to replace the granulate once a year to keep the full capacity in the dehumidifier. This is included in our Service agreement.

Can I change the granulate myself?

Yes you can. The granulate needed for the exchange is delivered in a package. How do the replacement is described in the manual.

Dehumidification methods

Which one is better depends on the environment. Here we make an effort to describe the pros and cons.

What is heat condensation and what makes it so efficient?

Heat condensation is a new technology invented by Airwatergreen. The technology combines the capability to bring out the humidity (water) from the air and at the same time not wasting energy.

It is designed around a physical phenomena called over-saturation. This means that in one step of the process the humidity is removed from the air in a treatment where the air can not hold more humidity, and the humidity is then released from the air. This step is handled in a closed chamber making it independent to the surrounding temperature. It also keeps all the energy added to the process inside the building or construction (see picture below).

This makes heat condensation very energy efficient and independent of the temperature of the air. Warm, dry air is produced in one end of the unit and water comes out of a tap at the other.

Heat condensation is energy efficient in all temperatures down to sub zero temperatures.

Is heating the air a good method?

Keeping the air warm can hardly be considered as a method for dehumidification as it doesn’t remove any water from the air.

Warming up the air will however bring down the level of relative humidity (Rh) due to the fact that warm air can “hold” more humidity than cold air. No water is removed from the air of the building so the heating needs to be kept on endlessly.

What about ventilation?

Ventilation is not to be considered as dehumidification and maybe not even a way to handle air humidity. This method is quite unreliable as it totally depend on the outdoor climate. Maybe you end up bringing in more humidity to the building instead of removing? Would it be advisable to open the window to ventilate humidity on a rainy day??

Ventilation is used quite often as it is considered a budget solution. But ventilation may create more problem than it sort. This is typically the situation when the ventilation bring in warm humid air into the attic or the coll crawl space during the summer – not an advisable method!

How to use cold condensation?

Waterdrops are created on a cold surface – this is common knowledge. This depends on the fact that cold air can not contain the same amount of humidity as warm air. This fact can be used in dehumidification as it actually brings out the water from the air. But at the same time this phenomena is also the root cause to corrosion and mold build up in may buildings and constructions!

To use cold condensation as a method for dehumidification the air has to be warmed up again after the condensation. Otherwise the relative humidity will remain at the same high level.

This means that this method can only be used down to a certain temperature to avoid ice build-up at the cold surface. And energy is needed to keep the air warm unless you are in a tropical climate.

What is sorption dehumidification?

Sorptions dehumidification is considered as the firts modern dehumidification method created in the 50-th in Sweden to dehumidify in the Swedish climatic conditions. Energy efficiency was not on the agenda at the time and didn’t matter. Over the years this method has used in many installations.

The draw-back with sorption is that it releases vapour – warm air with a high level of humidity that has to be removed. Typically through a hole in the wall.

This makes it difficult to install and a lot of energy is vaste through the hole in the wall. It has been a popular method to use as there has been no alternatives available.