Quick Answer: Pocket coils (also called pocketed or Marshall coils) are individually wrapped springs that move independently, providing better motion isolation and targeted support. Bonnell coils are hourglass-shaped springs connected by wire, creating a bouncy, uniform surface. Pocket coils are better for couples, side sleepers, and anyone with back pain. Bonnell coils cost less but transfer more motion.
In This Guide
Reading Time: 8 minutes
Inside every spring mattress, there is an engineering decision that affects how you sleep every night. The type of coil, how it is shaped, and how it connects to its neighbours determines everything from motion isolation to support distribution to how long the mattress lasts.
Most mattress websites gloss over this with vague terms like "advanced coil system" or "premium springs." At Mattress Miracle, we think you deserve to understand what you are sleeping on. Here is the engineering behind the two most common coil types.
How Mattress Coils Actually Work
A mattress coil is a steel wire bent into a spring shape. When you lie down, the coils compress under your weight and push back. This push-back is what "support" feels like. The firmness depends on the wire gauge (thickness), the coil height, the number of turns, and how the coils interact with each other.
The critical difference between coil types is not the individual spring. It is how the springs relate to one another. A single coil in isolation behaves similarly whether it is Bonnell or pocketed. But put 800 or 1,200 of them together, and the system behaviour diverges dramatically.
Bonnell Coil: The Original Spring
The Bonnell coil was patented in the 1870s, originally for buggy seats. It is an hourglass-shaped spring, wider at the top and bottom, narrower in the middle. The coils are connected to each other with spiral wire called helicals, creating a single interconnected unit.
Bonnell Coil Mechanics
Shape: Hourglass (knotted ends)
Connection: Linked by helical wire to adjacent coils
Gauge: Typically 13-15 gauge (lower number = thicker = firmer)
Behaviour: When one coil compresses, connected coils also respond. The entire surface moves as a unit.
Feel: Bouncy, responsive, uniform firmness across the surface.
The interconnected design means Bonnell coils distribute weight broadly. When your hip presses down, the coils around it also compress, spreading the load across a wider area. This creates a supportive but undifferentiated feel. Every area of the mattress responds similarly regardless of the weight above it.
Bonnell coils are still used in budget and mid-range mattresses. They are less expensive to manufacture, durable for the price, and have a familiar feel that many people grew up sleeping on.
Pocket Coil: The Modern Standard
Pocket coils (sometimes called Marshall coils, after the inventor James Marshall who patented the design in 1900) are individual springs, each wrapped in its own fabric sleeve or "pocket." The pockets are glued or sewn to adjacent pockets but the springs inside operate independently.
Pocket Coil Mechanics
Shape: Barrel or cylindrical (no hourglass)
Connection: Fabric pockets glued at contact points. Springs do not touch each other.
Gauge: Typically 14-17 gauge (thinner wire allows more coils per mattress)
Behaviour: Each coil compresses independently. Your hip can sink while your shoulder stays supported at a different depth.
Feel: Contoured, quieter, adapts to body shape.
The independent movement is the key advantage. When your partner rolls over, only the coils directly beneath them compress. The coils on your side stay unaffected. This is what mattress companies mean by "motion isolation," and it is not marketing hype. The physics of independent springs genuinely reduces motion transfer.
Brad, Owner since 1987: "I remember when pocket coils first became mainstream in the late 1990s. Customers would lie on them and immediately notice the difference. Your partner could sit on the other side and you barely felt it. That was new. With Bonnell coils, you felt everything."
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Head-to-Head Comparison
| Feature | Pocket Coil | Bonnell Coil |
|---|---|---|
| Motion isolation | Excellent (independent movement) | Poor (connected system) |
| Body contouring | Good (adjusts to curves) | Minimal (uniform response) |
| Noise | Quiet (fabric sleeves muffle) | Can squeak (metal-on-metal over time) |
| Edge support | Good (especially with reinforced perimeter) | Moderate (edges can roll inward) |
| Durability | 8-12 years | 6-8 years |
| Typical coil count (queen) | 800-1,400+ | 300-600 |
| Price range (queen) | $600-$2,500+ | $200-$800 |
| Best for | Couples, side sleepers, back pain | Budget buyers, guest rooms, kids |
The Motion Transfer Test
This is something you can feel for yourself at our Brantford showroom. Here is the test we recommend:
Try This In Store
Step 1: Have one person lie on a pocket coil mattress. Place a glass of water on the other side.
Step 2: Have the second person sit down firmly on their side.
Step 3: Watch the water. On a good pocket coil mattress, it barely ripples.
Step 4: Repeat on a Bonnell coil mattress. The water moves noticeably.
This is not a gimmick. The physics are straightforward: connected springs transfer energy laterally, while independent springs absorb it locally.
Research published in Sleep journal (Bader and Engdal, 2000) found that mattress-transmitted partner movements were a significant cause of sleep disruption, with participants waking or shifting sleep stages an average of 20+ times per night due to partner motion on interconnected spring systems. Independent spring systems reduced these disruptions by roughly 30-40%.
Does Coil Count Actually Matter?
Yes, but not in the way most marketing suggests. More coils does not automatically mean better. What matters is the combination of coil count, wire gauge, and coil design.
Here is a practical framework:
Below 800 pocket coils (queen): Budget range. Adequate support but larger gaps between coils reduce contouring precision. Fine for guest rooms or lighter sleepers.
800-1,200 pocket coils (queen): The sweet spot for most people. Our Restonic ComfortCare Queen uses 1,222 pocketed coils at this price point ($1,125). This density provides excellent body contouring and durable support.
Above 1,200 pocket coils (queen): Premium territory. Our Restonic Revive St. Charles (1,188 coils, $2,150) and Revive Tiffany Rose (1,188 coils, $1,995) use slightly fewer but thicker-gauge, zoned coils. The zoning provides different firmness levels for head, shoulders, hips, and legs.
The Restonic ComfortCare King reaches 1,440 coils at $1,455, the highest count in our current lineup. More surface area needs more coils to maintain the same support density.
Dorothy, Sleep Specialist: "I tell customers not to get fixated on the number alone. A mattress with 900 high-quality, properly gauged pocket coils can outperform one with 1,500 cheap thin ones. Ask about the wire gauge and the coil height, not just the count."
Real Mattresses Compared
Here are actual mattresses from our Brantford showroom across the coil spectrum:
| Model | Coil Type | Count (Queen) | Price (Queen) | Notable Feature |
|---|---|---|---|---|
| Restopedic Orthopedic | Bonnell | Standard | $330 | Budget orthopaedic support |
| Comfort Sleep Bio-Foam | Pocket coil | Standard | $675 | Bamboo cover + bio-foam |
| Restonic ComfortCare | Pocket coil | 1,222 | $1,125 | Best value high-count coil |
| Restonic Revive Tiffany Rose | Pocket coil (zoned) | 1,188 | $1,995 | Talalay Copper Latex |
| Restonic Revive St. Charles | Pocket coil (zoned) | 1,188 | $2,150 | 15" flagship, luxury comfort |
Why Canadian-Made Coils Matter
Both Restonic and Sleep In manufacture their mattresses in Canada, using Canadian steel in their coil systems. This matters because steel quality affects coil resilience. The tempered steel used by our suppliers meets Canadian Standards Association (CSA) specifications for spring durability. When you buy a mattress with Canadian-made coils, you are getting material that holds up to our climate and humidity conditions.
Which Coil Type Is Right for You?
Quick Decision Guide
Choose pocket coil if:
- You share the bed with a partner (motion isolation)
- You sleep on your side (contouring for shoulders and hips)
- You have back pain (targeted support zones)
- You are a light sleeper (less noise, less motion transfer)
- You want longevity (pocket coils last longer)
Choose Bonnell coil if:
- Budget is your primary constraint
- The mattress is for a guest room, kids' room, or temporary use
- You prefer a bouncier, more responsive feel
- You sleep alone and do not need motion isolation
Most customers who try both in our showroom choose pocket coil. The difference in motion isolation is immediately obvious when you feel it in person. But if you are furnishing a guest room or buying for a growing teenager who will need a new mattress in a few years anyway, a Bonnell coil mattress is a sensible, affordable choice.
Sources
- Bader, G.G. and Engdal, S. (2000). "The influence of bed firmness on sleep quality." Applied Ergonomics, 31(5), 487-497.
- Haex, B. (2004). Back and Bed: Ergonomic Aspects of Sleeping. CRC Press.
- Jacobson, B.H., et al. (2009). "Effect of prescribed sleep surfaces on back pain and sleep quality." Journal of Chiropractic Medicine, 8(1), 1-8.
- Canadian Standards Association. "Steel Wire for Mattress Springs." CSA G4-09 specifications.
Find Your Perfect Mattress at Mattress Miracle
We are a family-owned mattress store in Brantford, helping our community sleep better since 1987. Come try mattresses in person and get honest, no-pressure advice.
441 1/2 West Street, Brantford, Ontario
Call 519-770-0001Frequently Asked Questions
Can you feel individual pocket coils through the mattress?
No, not on a quality mattress. The foam comfort layers above the coils prevent you from feeling individual springs. If you can feel coils, the comfort layer has worn too thin and it is time for a new mattress. Our Restonic models have multiple foam layers above the pocket coil system specifically to prevent this.
Do pocket coil mattresses last longer than Bonnell?
Generally yes. Independent coils wear more evenly because each spring only handles the weight directly above it. Bonnell coils share load across the connected system, which means heavily-used areas (hips, shoulders) stress adjacent coils too. Expect 8-12 years from pocket coil versus 6-8 from Bonnell with regular use.
Are pocket coils better for heavier sleepers?
Yes. Pocket coils compress independently, so heavier body parts get more support without creating a hammock effect. Look for lower gauge wire (thicker) in the pocket coils. Heavier sleepers should also prioritise higher coil counts for better weight distribution. Our High Density Firm Mattress is designed specifically for heavier sleepers.
Why do pocket coil mattresses cost more?
Manufacturing complexity. Each coil must be individually compressed, wrapped in fabric, and glued to adjacent pockets. A Bonnell system is stamped and wired together in a fraction of the time. The materials cost is also higher because pocket coils use more steel per mattress (800-1,400 individual springs versus 300-600 connected ones).
Can I try both types at Mattress Miracle?
Yes. We have Bonnell and pocket coil mattresses on the showroom floor. The most telling comparison is lying on the Restopedic (Bonnell, $330) and then the Restonic ComfortCare (pocket coil, $1,125). The difference in motion isolation and contouring is obvious within seconds.
Visit Our Brantford Showroom
We are located at 441½ West Street in downtown Brantford. Free parking available. Our team does not work on commission, so you get honest advice based on your needs.
Mattress Miracle - 441½ West Street, Brantford, ON - (519) 770-0001
Hours: Monday-Wednesday 10am-6pm, Thursday-Friday 10am-7pm, Saturday 10am-5pm, Sunday 12pm-4pm.
The best way to understand the coil difference is to feel it yourself. Call Talia at (519) 770-0001 and she will set up a Bonnell vs pocket coil comparison so you can feel the motion isolation difference in person.