ONNI LONDON+ · Guides
What a hybrid mattress is
A hybrid is a mattress with two different systems doing two different jobs. Underneath, a pocket spring system carries the load. Above it, foam layers shape to the body. Neither does the other's work.
The spring system
A pocket spring is a steel coil sealed inside its own fabric pocket. Because each one is separate, it compresses only where weight is applied. Press one and its neighbour barely moves, which is why movement on one side of a pocket sprung bed is not felt on the other.
Two numbers describe them. Gauge is the thickness of the wire, and a lower gauge number means thicker wire and a firmer spring. Count is how many there are. A higher count means each spring covers less area and the surface follows the body more closely.
Count is worth treating carefully. It scales with the size of the bed, so a super king will always carry more springs than a double of the same design, and a very high number can be reached by using two thinner layers rather than one better one. The useful question is the count for the size you are buying, and what gauge the wire is.
The comfort layer
Above the springs sit the foams. These do not support you, they shape to you: filling the gap at the waist, letting the shoulder in, spreading pressure at the hip. This is the layer that decides how a bed feels, and the layer that wears out first.
How a hybrid compares with all foam
| Pocket spring hybrid | All foam | |
|---|---|---|
| Support comes from | Steel coils | Foam density |
| Airflow | Open space around every spring | Closed cell structure |
| Movement transfer | Contained to where the weight is | Absorbed across the surface |
| Edge | Holds shape when you sit on it | Tends to compress |
| What ages first | The foam above the springs | The whole mattress |
The reason hybrids exist is that foam is very good at contouring and not very good at holding a body up for twenty years, and steel is the reverse. Putting each where it is strongest gives a bed that follows the body at the surface and holds its shape underneath.
What zoning adds
Zoning varies the spring response along the length of the mattress rather than making it uniform. The hips meet firmer springs than the waist, the shoulders are allowed in further than the ribs. A body is not evenly heavy, so an evenly firm surface is wrong somewhere by definition.
How the Perennial is built
, twenty centimetres of individually pocketed springs in seven zones, up to 2,000 springs in a super king. Heavier two millimetre wire under the hips and shoulders, one point eight millimetre elsewhere. Above it, a fifteen centimetre comfort layer that lifts out and changes.
Thirty five centimetres in total. The springs are guaranteed for 25 years. The comfort layer is the part designed to come out.
Every layer, with its job.