Silentnight Comfort Breathe Plus 2100 King Size Mattress
The Silentnight Comfort Breathe Plus 2100 is a medium-feel pillowtop mattress built around 2,100 springs in total: 1,500 nano springs for contouring and 600 Mirapocket springs for zoned support underneath.
- Soft pillowtop that stays cool
- Nano springs contour to your body
- 60-night trial & 5-year guarantee
£959
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Silentnight Comfort Breathe Plus 2100 Mattress
More available sizes
Mattress details
Mattress
Silentnight Comfort Breathe Plus 2100 Mattress
Size
Firmness
Medium
Construction
Foam
Pocket Spring
Depth (cm)
30
Layers
7
Layer Details
Pillowtop sleep surface
A cushiony pillowtop in a naturally hypoallergenic fabric, which means immediate softness the moment you lie down. It's also a sensible choice if dust or allergens bother you at night.
Comfort Breathe+
An Airloft comfort layer that Silentnight positions as a cooler, cocooning alternative to traditional foam, claiming 18x more breathability. In practice that means pressure-relieving softness with less heat build-up than a standard foam layer.
1500 nano springs
A layer of 1,500 ultra responsive nano springs that contour to your body. Because springs allow air to move where foam can't, this layer also helps the mattress breathe.
Spring insulator layer
A polyester insulator layer with enhanced breathability, sitting between the comfort layers and the main spring unit. It keeps the layers above from settling into the springs below.
600 Mirapocket spring unit
600 Mirapocket springs sit in individual pockets and respond independently to movement, which means zoned support and better spinal alignment. It also helps limit motion transfer if you share a bed.
Protective Layer
This layer disperses pressure from the spring unit across the mattress. The aim is a longer usable life rather than any change to how it feels.
Durable case
A soft, durable outer case designed to keep the mattress comfortable for years. It's the housekeeping layer rather than a comfort feature.
Layer details from silentnight.co.uk product page, September 2026.
Key benefits
- 75cm each for couples: Two people sharing get 75cm of width apiece, enough to change position at night without negotiating for territory.
- Movement stays on one side: The 600 Mirapocket springs respond independently, which means an early alarm or a restless night is far less likely to travel across 150cm of mattress.
- Length for taller sleepers: At 200cm, the UK king adds 10cm over the UK double, a real difference if one of you is approaching six foot.
- Cooler across a shared bed: Two bodies generate more heat than one, so the Airloft layer's breathability matters more in a king than it would in a single.
- Soft surface, wide platform: The cushiony pillowtop feels softer than the medium rating suggests, and in this width each sleeper settles into their own patch of it.
This size suits you if...
You share the bed every night and have started to feel hemmed in on a UK double, especially if you and your partner keep different hours and want movement kept to one side. It also fits if one of you is tall enough to appreciate the 200cm length, or if a dog has quietly claimed a share of the bed and 135cm no longer stretches to three.
Consider another size if...
Your bedroom falls short of the 2.7m x 2.9m we suggest for a UK king. We'd recommend the UK double instead, which is 15cm narrower and 10cm shorter, and needs at least 2.6m x 2.8m by our guidance.
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FAQ's
Is the Comfort Breathe Plus 2100 UK king good for couples?
It suits couples well. You get 75cm of width each, comfortably more than a UK double offers, and the 600 Mirapocket springs move independently so one person shifting or getting up disturbs the other less. The medium pillowtop feel works for most sleeping positions, although heavier front sleepers may find it a little soft.
Will I feel my partner get up early on the UK king?
Less than you would on most sprung mattresses. The Mirapocket springs sit in individual pockets and compress only where weight lands, so an early riser's side of the bed moves without dragging yours with it. Across 150cm of width, that separation is easier to feel than on a narrower size.
Is the UK king long enough for someone over six foot?
At 200cm it gives a six-footer clear space above the head and below the feet, which the 190cm length of a UK double doesn't. If length is your main concern, the UK king solves it; the UK super king is the same length, just 30cm wider.
What room size do I need for this mattress in a UK king?
We suggest at least 2.7m x 2.9m for a UK king, which leaves room to walk round the bed and open drawers without shuffling sideways. That's our own guidance rather than Silentnight's. Newer master bedrooms can be tighter than they look once wardrobes go in, so measure before you commit.
Does the pillowtop feel different in the king size?
The construction is identical across every size, so the soft first contact and Airloft breathability are the same. What changes is how you use it: with 75cm each, both sleepers settle into their own area of the pillowtop rather than rolling towards a shared dip, and the cooling layer has two people's heat to manage.