Balanced air distribution
AC duct installation in Al Mahjar
In Al Mahjar, south Jeddah, AC duct installation needs careful design because most buildings are modern villas with open-plan spaces and multiple rooms. We size the ducts and branches to match the unit, insulate cold duct against Jeddah's humidity, and balance airflow at each diffuser.
- Sized branches
- Sealed insulation
- Clean return path
Clients We're Proud to Serve
Organisations and companies that trusted Alrabih with their projects.
When you need a properly designed duct fit
- 1
One room cold, another warm
The unit runs but one room is too warm while the next is too cold. The cause is usually unbalanced branches or a diffuser that was never adjusted, not a fault in the unit itself.
- 2
Moisture and sweating on the ceiling
In Jeddah's humid air, uninsulated cold duct sweats on the outside and water collects on the plasterwork. Proper insulation with Armaflex or Kimmco stops the problem before it damages the ceiling finish.
- 3
Installing a concealed unit in a new build
The right time to fit duct properly is during the fit-out, before the false ceiling closes. We agree plenum dimensions, branch sizes and the return-air route at the survey before any work starts.
Who it's for
Fitting a concealed unit in your new villa
Before the false ceilings close, we design the plenums, branches and return-air route to suit the unit and each room in the villa.
Ask on WhatsAppSweating ceiling and uneven airflow in your building
We inspect the existing branches and return-air path, re-insulate the cold duct, and set the dampers so temperature evens out across every section of the building.
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What the duct installation covers
- Supply and return plenums
- Sized branch to each room
- Armaflex or Kimmco insulation
- Diffuser balancing with dampers
- Airflow check before ceiling closes
How we work
How we work
- 1
Site and unit survey
We measure the rooms and study the unit's data and plenum spec, and we settle the return-air route before deciding on branch sizes.
- 2
Design branches and plenum
We size each branch so it takes the right share of air without starving rooms farther from the unit, and we plan a return path with a correctly sized intake opening.
- 3
Fit and insulate
We fix the plenums and branches using SMACNA-standard duct, then insulate every cold surface with a sealed layer that stops sweating in Jeddah's high humidity.
- 4
Balance and hand over
We set each diffuser damper and check airflow in every room with you before the false ceiling is closed, then leave the site clean.
Designed duct or just connected duct?
| Alrabih | The usual way | |
|---|---|---|
| Branch sizing | Calculated per room | Connected without sizing |
| Return air | Routed with a sized intake | Left to chance |
| Duct insulation | Sealed against sweating | Thin or absent |
| Diffuser balance | Damper set per room | All diffusers fully open |
| Pre-closure airflow check | Done with you before closing | Faults found after ceiling closes |
Everything your AC needs, from one team
From system design and duct fabrication to installation, commissioning and maintenance.
Split AC installation
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Some of our work
Ductwork, rooftop units and diffusers, from work we've completed in Jeddah.
Customer reviews
What our customers say
- Muhammadramzan 2641
“MashaaAllah. Services are so good. Behaviour and kindness 100/100. Prices are less then Market. Fully recommended”
- shahzeb armani
“Wow. Prices are so comfortable. Outstanding services. People are so talented and nice”
- Tawfik AlyawerLocal Guide
“U can find all u need for air conditioning”
Your satisfaction matters to us! If you had a great experience with us, we'd love a 5-star rating and a kind review.
Worked with us? Leave a reviewService areas
We come to you anywhere in Jeddah
From Al Shiraa and Al Yaqout in the north to Al Thaghr and Al Quraiyat in the south, with our base in Al Aziziyah.
What sets this district apart
Al Mahjar is a modern residential area of detached and semi-detached villas, most built in recent years with spacious interiors and open-plan designs that need even air distribution throughout. Central ducting here beats split units because it covers one or two storeys efficiently, but poor design leaves warm and cold spots, especially in rooms far from the outdoor unit.
Al Mahjar sits in south Jeddah, a district of modern, detached villas with spacious architectural designs.
Most modern villas in Al Mahjar use one or two central AC units to cover the ground and first floors.
The AC setup in Al Mahjar
- 1
Central duct run from the outdoor unit
Main ducts extend from the outdoor unit through suspended ceilings or floors to all villa rooms.
- 2
Secondary branches to each room
From the main duct, smaller branches run to each room with careful calculation of outlet sizes and distances.
- 3
Plenum box and main filter location
The plenum is mounted near the indoor unit, holding the main filter and dampers that control flow to each branch.
Before the visit
Before our visit in Al Mahjar
- 1
Confirm outdoor and indoor unit locations
Tell us exactly where the outdoor and indoor units will sit (which room or closet), and whether anything blocks the run between them.
- 2
Provide architectural plans or villa layout
The villa's floor plans showing room positions, suspended ceilings and columns help us calculate duct lengths and branches accurately.
- 3
Ensure access to suspended ceilings or floors
Check that we can safely access suspended floors or ceilings to run the ducts without damaging interior finishes.
More districts for AC duct installation
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FAQ
Questions about AC duct installation
Why does duct in Jeddah sweat more than elsewhere?
Jeddah's outdoor air carries high moisture because of its coastal location. When that air touches a cold duct surface, the moisture condenses immediately. Insulating with a thick enough layer of Armaflex or Kimmco, with all joints sealed, raises the outer surface temperature above the dew point and stops the sweating.
Does a longer branch deliver less air to the room?
Yes, a longer branch resists airflow more than a short one. This is why we size each branch individually, so near and far rooms receive balanced quantities of air, and we complete the adjustment with dampers during start-up.
How do you size the return-air opening?
The intake opening must be large enough so the unit does not work against negative pressure that strains it. We check the unit data and plenum requirements and decide size and position at the survey, because placing it behind a closed door or away from occupied areas changes the calculation.
Does a large room need more than one air outlet?
Usually, yes. A long majlis or a wide living room cannot be served by one outlet, because the air cools one end and leaves the other. We spread the outlets along the room, split the branch between them, and keep them away from the return grille so cool air does not go straight back to the unit.
Does the duct material affect sweating and airflow balance?
Yes. Sheet metal duct holds its shape under air pressure, so flow quantities stay as designed. Flexible duct can compress or sag, changing its cross-section and upsetting the balance. We therefore fabricate the main branches from galvanised sheet in our workshop and use flexible duct only for the shortest possible connection at each diffuser.
My villa is very spacious, will one duct run cover it?
It depends on the villa's size, outdoor unit location, and layout. We visit to assess distances, heights and openings before advising on the right number of units and duct runs.
Where exactly does the outdoor duct outlet sit on the villa?
The outlet is usually on the rear or side wall of the villa, away from main windows and the front entrance. It needs to be accessible for later maintenance and cleaning.
Jeddah's high humidity damages cold duct, how do you protect it?
We insulate all cold duct with thick foam to stop condensation forming and leaking onto the villa's interior walls and ceilings.
Rooms far from the unit are cooler than those near it, why?
If the duct outlets (diffusers) are not balanced in each room, nearby rooms get more air and far rooms get less. We need to balance airflow using control dampers on each branch.
