Micro-springs: what the second layer of springs does, and what it does not
Micro-springs, mini springs, comfort springs: they are all the same idea. A layer of small pocket springs, three to five centimetres tall, placed above the main spring unit or on top of a foam core. They are how spring counts reached 3,000, 5,000 and beyond. Here is what they actually do.
What they are
Ordinary pocket springs but small: a few centimetres tall, a couple of centimetres across, in their own fabric pockets, in a sheet that sits in the comfort layers. A king-size layer might hold 1,000 to 2,000 of them. The wire is thin, because each spring only has to carry a small share of your weight.
What they add
- A responsive, lively feel in the comfort layer, where foam is either still (memory foam) or bouncy (latex). Micro-springs give a little give-and-return that people describe as "hotel-like".
- Air. A layer of springs breathes in a way a slab of foam cannot, so a micro-spring layer under a fibre or foam top helps a mattress run cooler.
- Contouring. Because they are small and independent, they follow the body more closely than the main unit, especially at the shoulder.
- Durability of feel. Springs do not take a body impression the way lower-density foam does.
What they do not do
- Support. A 4 cm spring cannot hold you up. Support comes from the main unit or the core underneath. A mattress with a micro-spring layer and a weak main unit is a soft mattress with a lively top.
- Justify the count. A "3,000-spring" mattress is usually 1,000 main springs plus 2,000 micro-springs. It is honest to state both; it is misleading to add them together as if they were the same thing. See 1,000 vs 2,000 pocket springs.
Where they belong
Between the comfort layer and the main spring unit, or on top of a foam core as the responsive element in a foam-based mattress. In the traditional premium trade they sit under a pillow-top with natural fillings; in hybrids they sit under foam or latex. They are a comfort-layer material, not a support material.
Micro-springs versus foam
| Micro-spring layer | Foam layer | |
|---|---|---|
| Feel | Lively, responsive | Still (memory) or bouncy (latex) |
| Airflow | High | Low (memory), medium (latex) |
| Body impression over time | Little | Depends on density |
| Motion transfer | Some | Little |
| Cost | Higher | Lower |
Reading the spec
Ask for the main spring count and the micro-spring count separately, the height of the micro-springs, and what sits above and below them. A spec that says "3,000 springs" and nothing else is hiding the split.
How we use them
The Hotel Bed has 1,000 micro-springs between its gel memory foam and its support foam, above a 2,000-spring five-zone main unit; we count them separately on the page. The New Parent uses a micro-spring layer on a foam core as its only springs, for a little life in a mattress built for stillness.
The short version
- Small springs in the comfort layer: lively feel, airflow, contouring.
- Not support. The main unit or the core does that.
- Ask for main and micro counts separately.
- Best under fibre or foam in a premium build; a good way to make a foam mattress breathe.
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