Coolflex Hybrid CHILL Small Double Mattress
The Coolflex Hybrid CHILL is a medium-feel hybrid built around cooling, with a gel-infused memory foam layer designed to draw heat away from you and a stitched-in pillow top for softness on top of the springs.
- Cool gel foam regulates temperature
- Plush pillow top that springs back
- Helps keep your spine aligned
£449
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Coolflex Hybrid CHILL Mattress
More available sizes
Mattress details
Mattress
Coolflex Hybrid CHILL Mattress
Size
Firmness
Medium
Construction
Foam
Pocket Spring
Hybrid
Memory Foam
Depth (cm)
37
Layers
4
Layer Details
Pillow Top
A plush pillow top with up to 1200 mini pocket springs, working like a stitched-in mattress topper. You get that soft, cushioned first touch without needing to buy a separate topper.
Cool Gel Memory Foam
Memory foam infused with gel microbeads to regulate temperature and improve breathability, designed to draw heat away from the body. In practice, that means the contouring feel of memory foam with less heat build-up overnight.
Comfort Foam
Layers of Comfort Foam that cradle pressure points and relieve pressure across the whole body. Side sleepers should notice this most around the hips and shoulders.
Pocket Springs
Up to 800 individually pocketed springs that move independently to target support where you need it and keep your spine aligned. Independent movement also means less disturbance when a partner shifts position.
Layer details from mattressnextday.co.uk product page, September 2026.
Key benefits
- Real space for one: At 120cm across, the UK small double is 30cm wider than the UK single, which means a solo sleeper can starfish without an elbow hanging off the edge.
- Fits rooms a double cannot: It is 15cm narrower than a UK double, so a box room or studio keeps its walkway, and the door still clears the bed frame.
- Cooling that suits close quarters: Smaller rooms often run warmer, and the gel-infused memory foam is designed to draw heat away, which means less of that clammy overnight build-up.
- Plush surface without a topper: The stitched-in pillow top with up to 1200 mini pocket springs gives a soft first touch, useful in a guest room where you cannot fuss with extras.
- Support that ignores a restless guest: Up to 800 individually pocketed springs move independently, so on the occasional shared night one person turning over disturbs the other less.
This size suits you if...
You're a solo adult who has outgrown a single but can't spare the floor space a double demands, you're furnishing a box room, loft conversion or small second bedroom where every centimetre of width matters, or you're setting up a guest room that hosts the occasional couple rather than two people every night. Allow at least 2.4m x 2.8m of floor space and this size works comfortably.
Consider another size if...
You share the bed every night, because 120cm is snug for two adults long term, especially on a soft pillow top where you both settle towards the middle. We'd recommend the UK double instead; allow at least 2.6m x 2.8m for it.
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FAQ's
Is the Coolflex Hybrid CHILL small double big enough for two people?
For the odd night, yes. Couples staying in a guest room will manage fine, and the independent pocket springs limit disturbance when one person moves. As an every-night bed for two adults it's snug, and the soft pillow top means you'll both tend to roll towards each other, so regular sharers should look at the UK double.
What bedding fits the Coolflex Hybrid CHILL in a UK small double?
You'll need small double (4ft) fitted sheets, and one thing catches people out: this mattress is 37cm deep, which is taller than many fitted sheets are cut for. Check the sheet's stated depth before you buy. A standard double duvet works well on a small double and gives a generous overhang.
Will a small double Coolflex Hybrid CHILL fit in a box room?
Often, yes, and that's the point of the size. At 120 x 190cm it's 15cm narrower than a UK double, which can be the difference between a door that opens fully and one that doesn't. We suggest a room of at least 2.4m x 2.8m so you keep a usable walkway on one side.
How much bigger is a small double than a single for this mattress?
The UK small double is 30cm wider than the UK single, and the two are the same length at 190cm. That extra width is what makes it appealing for a teenager or solo adult who has outgrown a single: you get proper stretching room without the footprint jumping to a full double.
Does the Which? Best Buy apply to the small double size?
The award was given for double mattresses in January 2026, so strictly it applies to the UK double rather than the small double. The construction is the same across sizes, which is reassuring, but if the badge itself matters to you, only the UK double carries it directly.