Springs
Pocket, bonnell and continuous coil springs, and why coil counts inflate
Three spring units drawn at one scale. Every coil count printed under the three panels describes a 150 x 200 cm queen unit, the only size that allows a fair comparison of the three systems.
A mattress spring unit performs two jobs: carrying body weight and isolating the movement of one sleeper from the other. Carrying weight depends on wire gauge and coil geometry. Isolating movement depends on whether neighbouring coils are physically connected. Pocket, bonnell and continuous coil units answer those two jobs in three different ways, and the price gap between the three is narrower than Dubai showroom marketing suggests.
How does a bonnell spring unit carry load, and where does bonnell fail?
A bonnell unit uses hourglass shaped coils, knotted at both ends and tied to their neighbours by helical wires running the width of the mattress. Bonnell wire gauge runs 1.9 to 2.4 mm, the thickest wire in any domestic mattress, so a bonnell unit carries heavy sleepers for 8 to 12 years without losing height.
Coil count on a bonnell unit cannot rise far, because the hourglass profile needs clearance at the waist of each coil. A 150 x 200 cm bonnell mattress holds 300 to 450 coils, which works out at 100 to 150 coils per square metre. Any bonnell mattress advertising more than 500 coils in a queen size has either shrunk the wire gauge or counted something other than coils.
The helical ties are the structural weakness of every bonnell unit. Pressing one bonnell coil drags the neighbouring coils down through the helical wire, so a partner turning over at 3 am moves the entire sleeping surface. Bonnell mattresses in 150 cm width sold for AED 700 to 1,600 on Dubai retail floors in July 2026, and the system remains a defensible choice for a guest room or for one heavy sleeper sleeping alone.
Why does a continuous coil unit feel firm and transfer every movement?
A continuous coil unit is formed from one long steel wire per row, bent into repeating turns down the length of the mattress. Continuous coil wire runs 1.6 to 2.0 mm, and each row behaves as one stiff hinged strip rather than as independent springs, which makes support even along a row and rigid across rows.
Continuous coil construction is where spring count inflation began. Every turn of the wire is counted as a spring on the label, so a unit built from 14 rows of 60 turns is advertised at 840 springs. Those 840 turns belong to 14 pieces of wire, and 14 pieces of wire do not behave like 840 independent springs under a hip.
Motion transfer along a continuous coil row is total, because a row is literally one object. A sleeper pressing at the head of a row lifts and drops the same wire at the foot of that row. Continuous coil mattresses in 150 cm width sold for AED 600 to 1,300 in Dubai in July 2026, the cheapest sprung construction on the market and the firmest feeling of the three.
What makes a pocket spring unit independent, and what is an honest pocket count?
A pocket spring unit uses barrel or cylindrical coils, each sewn inside an individual fabric sleeve, with the sleeves glued or ultrasonically welded to each other at the sides. Pocket wire gauge runs 1.2 to 1.6 mm, thinner than bonnell wire, because each pocket coil carries only the load directly above that coil.
An honest pocket count for a 150 x 200 cm mattress runs 800 to 1,400 coils in the single main support layer, giving 267 to 467 coils per square metre. Zoned units change wire gauge across the width of the mattress, typically 1.6 mm under the hips and 1.4 mm under the shoulders, arranged in 3, 5 or 7 zones down the length.
Pocket units in Dubai started near AED 1,400 for a 1,000 coil 150 cm mattress in July 2026 and reached AED 6,000 for 7 zone units carrying latex and wool comfort layers. EN 1957 sets the durability test that separates the two price tiers: roll a 140 kg loaded cylinder over the mattress for 30,000 cycles, then record height loss and firmness loss against the original measurements.
Which spring system suits a couple, a heavy sleeper or a guest room?
Pocket springs suit couples, because motion transfer between neighbouring pockets stays low. Bonnell suits one heavy sleeper, because 2.4 mm wire outlasts 1.4 mm wire under a 120 kg load. Continuous coil suits a guest room at the lowest price per year of service. The table below sets the four measurable differences side by side.
| Property | Bonnell | Continuous coil | Pocket spring |
|---|---|---|---|
| Wire gauge | 1.9 to 2.4 mm | 1.6 to 2.0 mm | 1.2 to 1.6 mm |
| Coils per m2, queen | 100 to 150 | Not comparable, 14 wire rows | 267 to 467 |
| Motion transfer to a partner | High, through helical ties | Total along each row | Low, sleeves only |
| Service life before 20 mm height loss | 8 to 12 years | 5 to 8 years | 7 to 10 years |
| Dubai price, 150 cm, July 2026 | AED 700 to 1,600 | AED 600 to 1,300 | AED 1,400 to 6,000 |
Comfort layer thickness distorts every row of the table above. A bonnell unit under 80 mm of 35 kg/m3 foam outperforms a 1,200 pocket unit under 40 mm of 21 kg/m3 foam for the first five years, because the sleeper never reaches the spring unit through 80 mm of high resilience foam. Spring type sets the ceiling on mattress quality, and the comfort layer decides how much of that ceiling the sleeper feels.
How do mattress makers inflate a spring count, and what is the honest figure?
Four counting tricks account for almost every inflated spring number on a Dubai showroom label: adding a mini spring topper layer to the main count, quoting the super king count on a smaller size, counting both faces of a double sided unit, and counting turns of continuous coil wire. Each trick is detectable with one question about mattress size.
| Label claim | What the label counted | Honest support figure | Coils per square metre |
|---|---|---|---|
| 3,000 springs, 150 x 200 cm | 1,000 main coils plus a 2,000 mini spring topper layer | 1,000 support coils | 333 |
| 2,000 springs, 90 x 190 cm single | The count measured on a 180 x 200 cm super king unit | Around 570 coils | 333 |
| 1,600 springs, 150 x 200 cm | Coils counted on both faces of a double sided unit | 800 coils per face | 267 |
| 840 springs, 150 x 200 cm | Turns of continuous coil wire, 14 rows of 60 turns | 14 wire rows | Not comparable |
Coils per square metre defeats all four tricks at once. A 150 x 200 cm mattress covers 3.0 m2, so a 1,200 coil unit delivers 400 coils per m2. A 180 x 200 cm mattress covers 3.6 m2, so the identical 1,200 coils deliver only 333 per m2. Good pocket units land between 330 and 470 coils per m2.
Counts above 700 coils per m2 require wire below 1.1 mm, which lets the coils bottom out under a hip and adds cost without adding support. A queen mattress advertised at 3,000 pockets is running 1,000 coils per m2 on paper and is nearly always counting a mini spring layer that stands 30 to 40 mm tall and carries a fraction of the sleeper's weight.
Which three questions expose a mattress spec on a showroom floor?
Three questions separate a specified mattress from a marketed one, and all three demand a number rather than an adjective. Ask which mattress size the quoted coil count describes. Ask the wire gauge in millimetres and how many spring layers the unit contains. Ask the thickness and the density of the foam comfort layer above the springs.
- Which mattress size does the quoted coil count describe, and what is the count on the 150 x 200 cm or 180 x 200 cm size actually being bought?
- What is the spring wire gauge in millimetres, and does the unit stack more than one spring layer, for example a 30 mm mini coil layer above the main coils?
- How thick is the foam comfort layer above the springs in millimetres, and what is the foam density in kilograms per cubic metre?
The third question predicts returns better than the coil count does. A 1,000 pocket unit under 60 mm of 25 kg/m3 foam feels correct for roughly 18 months, then shows permanent body impressions while the pocket springs underneath still measure full height. The comfort layer, not the spring unit, is the component that fails first on nearly every mattress returned under warranty.