Installing a new AC unit should mean cool comfort and steady airflow from day one. But if your new air conditioner is not cooling, it can be frustrating and confusing, especially in Dubai’s extreme heat. As an experienced HVAC technician and electrician with over two decades of hands-on work in air conditioning systems, I’ve handled countless cases where new ACs fail to deliver cold air.
The problem isn’t always with the AC brand or unit itself. It often comes down to installation errors, electrical issues, or even minor problems such as airflow blockage or thermostat settings. If your air conditioning system is running but not blowing cold air, producing a damp smell, or constantly running without proper cooling capacity, this guide will help you troubleshoot and understand what’s wrong.
For accurate setup, energy efficiency, and long-term reliability, it’s always best to hire trusted AC installation experts in Dubai who ensure refrigerant tubing, drain lines, and circuit breakers are all correctly configured during installation.
Why Is My New AC Running But Not Cooling?
When a new air conditioner runs but doesn’t blow cold air, the issue could be mechanical, electrical, or related to installation quality. Below are the most common causes.
1. Incorrect Installation or Loose Connections
Improper installation is one of the leading reasons for cooling issues in new HVAC units. Even a small mistake such as a loose refrigerant connection, poor duct tape sealing, or uninsulated refrigerant tubing can reduce the unit’s efficiency.
During AC installation, every indoor unit, outdoor condenser unit, and coil unit must be leveled, sealed, and tested using digital gauges to ensure correct system pressure. If the electrical circuit board or wiring is poorly connected, your compressor or fan motor might not start correctly.
In Dubai’s hot and humid climate, missing insulation or an unsealed condensate drain can also cause frost forming on the evaporator coil, leading to poor airflow and higher energy costs.
2. Low Refrigerant Levels or Leaks
A refrigerant leak is another common reason for poor cooling performance. Even brand-new split AC systems can lose cooling liquid if the copper joints or refrigerant lines weren’t brazed properly.
Low refrigerant or gas pressure prevents the evaporator coils from absorbing heat, causing warm air or even ice buildup inside the unit. This affects the cooling capacity and increases your energy bills.
During professional AC maintenance or post-installation inspection, technicians use digital gauges to check refrigerant charge, inspect suction lines, and verify proper airflow through the evaporative coil.
3. Incorrect AC Sizing or Load Calculation
If your AC unit size doesn’t match your room’s cooling load, it won’t deliver the expected cool air. An undersized system runs continuously but never reaches the set temperature, while an oversized one cycles too quickly, wasting power.
Proper load calculation considers room size, insulation, number of occupants, and even local air pollution levels. Whether you have a mini split AC, window unit, or central air conditioning system, matching the SEER rating and system pressure to your space is essential.
Common Installation Issues That Affect Cooling
Electrical and Wiring Problems
Faulty wiring or voltage fluctuation can stop the compressor, condenser fan, or blower motor from running at full speed. A tripped circuit breaker or a faulty shutoff switch can also disrupt cooling. Always check that your electrical connections, float switch, and external shutoff switch are secure.
Dubai homes often experience voltage drops during peak hours, which can trigger safety cutoffs on the compressor or fan speed control system.
Blocked Airflow or Dirty Filters
A brand-new air conditioner can still suffer from blocked airflow. If the air filter, air ducts, or blower fan are clogged with dust buildup, cool air cannot circulate properly.
Replace or clean your air filter monthly, especially during Dubai’s dusty season. Restricted airflow can also cause a frozen evaporator coil, reduced air quality, and mold growth inside the coil unit.
Some models, such as TCL ACs or Mitsubishi Electric units, include a self-cleaning feature or smart filter design to maintain performance automatically.
Thermostat Settings or Calibration
Sometimes, your AC may not be cooling simply because of thermostat calibration errors. Check that it’s set to “Cool” and the fan speed is set correctly. For inverter or smart systems, verify the auto mode and temperature sensor location.
If the thermostat or indicator light isn’t responding, you might need to reset the system using the reset button or check for electrical faults in the control board.
Mechanical and Component-Related Issues
Faulty Compressor or Capacitor
If your compressor or capacitor isn’t working, the AC won’t circulate the refrigerant properly. This results in warm air and low suction pressure. A qualified HVAC technician can test these components and replace faulty parts safely.
Frozen Evaporator or Condenser Coils
A frozen evaporator coil occurs when there’s restricted airflow or low refrigerant. Similarly, dirty condenser coils or a clogged condensate drain can cause system strain. Clean coils improve heat exchange and reduce energy costs.
Outdoor Unit and Condenser Maintenance
The outdoor condenser unit faces harsh conditions in Dubai, with dust, sand, and high humidity reducing performance. Regular coil cleaning, condensate drain inspection, and fan motor testing are part of good AC maintenance practices.
Energy Efficiency and Modern AC Systems
Modern energy-efficient units such as inverter or VRF systems adjust compressor speed automatically to maintain stable temperatures. However, incorrect setup can lead to high DEWA energy bills, poor airflow, and system imbalance.
A properly installed system prevents heat traps, maintains consistent air quality, and supports energy savings year-round.
Cost and Maintenance Considerations
In Dubai, AC repair or troubleshooting typically costs between AED 2,000 and AED 6,000, depending on system type and issue. An Annual Maintenance Contract (AMC) can help avoid frequent repairs and keep your home cooling system in peak condition.
A full air conditioning appointment or inspection may include:
- Checking refrigerant lines for leaks
- Cleaning air filters and blower fans
- Inspecting drain line and condensate tray
- Measuring refrigerant pressure
- Testing blower motor and fan speed
- Verifying temperature sensor accuracy
When to Call a Professional AC Technician in Dubai
If your new AC still isn’t cooling after you’ve checked thermostat settings, air filters, and fan speed, call a professional HVAC expert immediately. Avoid DIY AC repair attempts that involve refrigerant or electrical components because these require certified handling.
A professional technician can diagnose refrigerant leaks, clean coils, check condensate drains, or use suction from a wet or dry vac to clear blockages. They’ll also ensure your cooling liquid, expansion valve, and furnace filter are functioning properly.
Conclusion
If your new air conditioner isn’t cooling properly, don’t panic. In most cases, installation quality, electrical setup, or refrigerant balance is the root cause. Having your system inspected by a licensed HVAC professional ensures your air conditioning system runs safely, efficiently, and delivers lasting cool comfort.
At Pro Electrician Dubai, our expert technicians specialize in AC installation, troubleshooting, and maintenance for residential and commercial HVAC systems. Whether it’s a split AC, central system, or heat pump, we ensure flawless installation and reliable cooling. Contact us today to schedule your inspection and keep your home perfectly cool all year.
Frequently Asked Questions
Why is my new AC running but not cooling the room?
Usually due to low refrigerant, poor airflow, or thermostat settings. A technician can test system pressure and diagnose the issue.
Could incorrect installation cause my AC not to cool properly?
Yes. Poorly sealed ducts, incorrect refrigerant charge, or wrong system sizing can cause weak cooling from day one.
How can I tell if my new AC has a refrigerant leak?
Look for hissing sounds, ice buildup, or a drop in cooling performance.
Can a clogged air filter stop a new AC from cooling?
Definitely. A dirty filter blocks airflow and affects indoor air quality.
When should I call a technician?
If your AC isn’t cooling even after basic checks, contact a professional immediately to prevent compressor or capacitor damage.
