Searching for “flexible air duct” often leads to a marketplace page. You’ll see dozens of near-identical listings. Real guidance on what to actually buy is usually missing. This guide fills that gap. It covers what flexible duct is, the types and sizes sold in Pakistan, how to judge quality, installation basics that affect your energy bill, and where to source it reliably.
What Is a Flexible Air Duct?
A flexible air duct (often just called “flex duct”) is a bendable tube. It carries conditioned air between your HVAC unit and the vents in each room. A coiled wire helix forms its core, wrapped in layers of polyester, aluminum foil, or PVC. This layered build lets it bend around obstacles in ceilings, walls, and tight spaces. Rigid galvanized steel ducting can’t do that without custom fabrication.
Pakistani installers use flex duct widely in both residential split/ducted AC systems and small commercial fit-outs. It installs faster and cheaper than sheet metal ducting. That matters most in renovation work, where cutting through existing structure isn’t practical.
Types of Flexible Duct Available in Pakistan
1. Insulated Aluminum Flexible Duct
This is the most common type for air conditioning work. It has an inner core — usually aluminum or a laminated polyester/aluminum layer — plus a middle layer of glass wool or foam insulation and an outer vapor barrier. Choose insulated duct whenever the run passes through a hot, unconditioned space, such as a ceiling void or roof space. The insulation stops cooled air from picking up heat (or losing it, in heating systems) before it reaches the room.
2. Non-Insulated Aluminum Flexible Duct
This is a bare corrugated aluminum tube with no insulation layer. It costs less and weighs less, but suits only short runs inside already-conditioned spaces — kitchen exhausts or ventilation work where temperature loss isn’t a concern.
3. PVC / ECOSOFT Flexible Duct
This plastic-based flexible duct works well for lighter ventilation duty. Installers use it for extractor fans and light commercial ducting where full HVAC-grade insulation isn’t necessary.
4. Glass Wool Wrapped Duct
Commercial and industrial installations across Pakistan favour this type. Fire rating and acoustic performance matter more here than in a typical home installation.
Brands Available Locally
The Pakistani market includes imported options such as , HVAC material distributors in Lahore, Karachi, and Islamabad also supply locally sourced and rebranded ducting.
Common Sizes Sold in Pakistan
Suppliers size flexible duct by internal diameter. Here’s what you’ll most commonly find from Pakistani suppliers and on local marketplaces:
| Size (inches) | Approx. mm | Typical Use |
|---|---|---|
| 4″ | ~100 mm | Kitchen/bathroom exhaust, small extractor fans |
| 6″ | ~150 mm | Single-room AC branch duct |
| 8″ | ~200 mm | Medium room or small hall branch duct |
| 10″ | ~250 mm | Larger rooms, small commercial branches |
| 12″ | ~300 mm | Main trunk runs, larger commercial spaces |
Local suppliers usually sell 25-foot rolls (about 7.6 metres) as standard. Many will cut custom lengths on request.
What Affects the Price of Flexible Duct in Pakistan?
Prices vary significantly by supplier. Rather than quote a figure that may already be outdated by the time you read this, here’s what actually drives the cost:
- Insulated vs non-insulated — the added glass wool/foam layer and vapor barrier push insulated duct prices higher
- Diameter — larger sizes use more material and cost proportionally more
- Brand/import origin — imported brands like typically sit at a higher price point than generic or locally rebranded duct
- Roll length — a full 25-ft roll usually costs less per foot than cut lengths
- Quantity — HVAC contractors and bulk buyers often get better per-unit pricing than single-roll retail purchases
Compare prices from at least two or three suppliers before you commit. Pricing on general marketplaces can vary widely between sellers for what looks like an identical product.
Installation Basics That Affect Performance
Installers can easily get flex duct wrong. A poorly installed run can quietly waste a meaningful share of your AC’s cooling capacity. Industry estimates put the efficiency loss from poor duct installation at around 10% in a reasonably good system, rising to 40% in a poorly installed one. Here are the fundamentals worth knowing before your contractor starts work.
Bends and Support
- Avoid tight bends. Sharp bends restrict airflow, and over time the duct’s inner core can collapse further at the bend point. As a rule of thumb, any bend needs a radius of at least one full duct diameter.
- Don’t compress the duct into undersized spaces. Squeezing flex duct into gaps smaller than its own diameter chokes airflow. This shortcut is common in tight ceiling voids, and it costs you cooling efficiency for the life of the installation.
- Support it properly. Flex duct needs support at regular intervals — don’t let it sag between two distant fixing points. Use wide support straps rather than thin wire or cord, which can dig into the duct.
- Extend it to full length. Excess slack bunched up in a duct run increases air friction and reduces airflow. Pull it reasonably taut instead of leaving it loose.
Insulation and Sealing
- Keep insulation continuous. Wherever the duct passes through a hot roof space, the insulation layer needs to stay intact and sealed at every joint. Gaps are where energy — and money — leak out.
- Seal every joint properly. Connections at the AC unit, plenum, and diffuser boots need tape and clamps, not just a push-fit. Proper sealing stops conditioned air leaking into the ceiling void instead of reaching the room.
If you’re hiring a contractor, ask them directly how they handle bend radius, support spacing, and joint sealing. A contractor who can answer clearly usually knows what they’re doing.
Where to Buy Flexible Air Duct in Pakistan
You generally have two routes.
General Marketplaces
Daraz, Ubuy, and similar sites suit small, one-off purchases — a single roll for a kitchen exhaust or a DIY job. Expect the usual marketplace trade-offs: mixed seller quality, limited technical support, and product descriptions that don’t always specify insulation type or fire rating clearly.
Specialised HVAC/Ducting Suppliers
These suit whole-house or commercial installations better. They typically stock a wider range of insulated and non-insulated options, advise on the right size for your system’s CFM (airflow) requirement, and often serve contractors directly with bulk pricing across major cities including Lahore, Karachi, Islamabad, Rawalpindi, Faisalabad, and Multan.
For anything beyond a single small duct run, choose a specialised supplier who can confirm insulation R-value, fire rating, and correct sizing for your system. That extra step is worth it compared to a generic marketplace listing. [LINK to your shop/contact page]
Buying Checklist
Before you order, confirm:
- Insulated or non-insulated — matched to whether the run passes through unconditioned space
- Correct diameter for your AC unit’s airflow requirement (undersized duct restricts airflow; oversized wastes material and space)
- Roll length needed, with a small allowance for bends and connections
- Fire rating, if required for a commercial installation
- Supplier can confirm brand/origin, not just a generic “flexible duct” listing
Frequently Asked Questions
What is the difference between insulated and non-insulated flexible duct? Insulated duct has a glass wool or foam layer between the inner core and outer vapor barrier. This layer prevents temperature loss as air travels through hot or cold unconditioned spaces. Non-insulated duct is a bare tube, suitable only for short runs within already-conditioned areas.
What size flexible duct do I need for my AC unit? Sizing depends on your unit’s airflow (CFM) rating and the length of the run. Ask a qualified HVAC technician to calculate this rather than guessing, since undersized duct restricts airflow and can strain the unit.
How long does flexible duct typically last? Quality insulated flex duct typically lasts 15–20 years with correct installation — proper support, no compression, sealed joints. Tight bends, moisture ingress, or physical damage from compression during installation can significantly cut that lifespan.
Can I install flexible duct myself? A confident DIYer can handle simple, short non-insulated runs, like a kitchen exhaust. Leave full HVAC duct runs to a professional, especially anything requiring correct sizing, insulation continuity, and sealed joints — installation errors are hard to spot once the ceiling closes up.
Is flexible duct as good as rigid metal ducting? Each has its place. Rigid ducting generally has lower air friction over long straight runs. Flexible duct installs faster, costs less, and works far better around obstacles. That’s why most residential AC installations in Pakistan mix both, using rigid trunk lines and flexible branch runs to individual rooms.
Final Word
Flexible duct is a small line item in the overall cost of an HVAC installation. But a poorly chosen or poorly installed run can quietly cost you money every single month your AC runs. Match the right insulated or non-insulated type to where it’s going, get the size right for your unit, and hold your contractor to proper installation standards for anything beyond a simple job.