Solutions
Humidity from Fresh Air
Fresh air is essential for ventilation, but in the UAE it can introduce a significant amount of heat and moisture into the building.
What you are seeing
Indoor humidity may rise when hot and humid outdoor air is introduced through a fresh-air system, FAHU, ventilation opening or direct outdoor-air connection. This can lead to uncomfortable conditions, condensation and additional load on the air-conditioning system, even when the indoor temperature remains low.
Why it happens
The amount of moisture carried by outdoor air depends on its temperature and humidity, not only on the airflow volume. During humid UAE conditions, even a controlled supply of fresh air can introduce a substantial moisture load. A conventional fresh-air or air-conditioning system may cool the incoming air without removing enough moisture to maintain stable indoor humidity. The result can be a space that is cool but still feels damp.
The ONYX NOVA approach
ONYX NOVA assesses the required fresh-air volume, outdoor design conditions, existing ventilation system and the way fresh air is distributed and mixed inside the property.
ONYX Aero is designed for projects requiring filtered fresh-air supply, exhaust air, dehumidification and total-heat recovery within one solution. Its separated incoming and outgoing air streams exchange energy, helping reduce the thermal and humidity load of outdoor air before active treatment.
ONYX Core can treat a controlled amount of outdoor air when it is correctly mixed with indoor return air at the unit inlet. The permitted fresh-air volume depends on the selected model, outdoor conditions, mixing arrangement and duct design. It must not be treated as the unit's total supply airflow.
ONYX Alpha can provide balanced fresh-air and exhaust ventilation with energy recovery, helping reduce the load created by untreated outdoor air. However, Alpha is not a dehumidifier and must be combined with an appropriate humidity-control solution where active moisture removal is required.
The final configuration is determined through an engineering assessment of airflow, temperature, humidity, energy recovery, ductwork and compatibility with the existing HVAC system.
Technical note: Final equipment selection and expected performance depend on site conditions, system design, outdoor-air conditions and professional assessment.
Suitable product families
Product families typically considered.
Core
ONYX Core 48
Concealed ducted dehumidification and air treatment
View detailsCore
ONYX Core 70
Concealed ducted dehumidification and air treatment
View detailsCore
ONYX Core 120
Concealed ducted dehumidification and air treatment
View detailsAero
ONYX Aero 70
Fresh-air treatment, ventilation and dehumidification with total-heat recovery
View detailsAlpha
ONYX Alpha
Fresh-air ventilation with total-heat recovery
View detailsRelated reading
Understand the background.
How does outdoor fresh air increase indoor humidity?
Fresh air is necessary for indoor air quality. Untreated, outdoor air in the UAE also carries a significant moisture load indoors.
Read articleCore versus Aero: which system is appropriate?
Core is recirculation-led with controlled fresh-air mixing. Aero is fresh-air-oriented with integrated energy recovery.
Read article