Coolflex Hybrid CHILL King Size 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
£499
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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
- Proper space for two: At 75cm each for two people sharing, you can both stretch out without staking claims to the middle.
- Less disturbance on different schedules: Up to 800 individually pocketed springs move independently, so an early alarm on one side is less likely to wake the person still sleeping.
- Length for taller sleepers: The UK king is 10cm longer than the UK double, which matters more than width if one of you is nudging six foot.
- Cooling across a bigger surface: The gel-infused memory foam draws heat away, and with more mattress each there's less shared body warmth to begin with.
- A plush surface you both feel: The stitched-in pillow top with up to 1200 mini pocket springs gives that cushioned first touch across the full 150cm width.
This size suits you if...
You share the bed every night and a double has started to feel cramped, especially if one of you sleeps hot and blames the other. It also suits couples on mismatched schedules, where one of you is up hours before the other, or households where the dog treats the bed as its own. And if either of you is tall, the 200cm length is a genuine relief.
Consider another size if...
Your bedroom is smaller than the 2.7m x 2.9m we suggest for a UK king, or you sleep alone. In either case we'd recommend the UK double instead, which needs at least 2.6m x 2.8m.
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FAQ's
How much space does each person get on a UK king Coolflex Hybrid CHILL?
You get 75cm each for two people sharing, which is a noticeable step up: the UK king is 15cm wider than the UK double. On a medium-feel mattress with a plush pillow top, that extra width means you can change position freely without meeting in the middle.
Will the Coolflex Hybrid CHILL king stop me feeling my partner get up?
It should help. The base layer uses up to 800 individually pocketed springs that move independently, so movement on one side transfers less to the other. Combine that with 75cm of width each and a partner leaving hours before you is far less likely to drag you awake with them.
Is the Coolflex Hybrid CHILL UK king long enough for someone over 6ft?
At 200cm (6ft 6in) long, it gives most tall sleepers comfortable clearance. The UK king is 10cm longer than the UK double, and for anyone approaching or past six foot that length is often the real upgrade, more so than the extra width.
What room size do I need for this mattress in a UK king?
We suggest at least 2.7m x 2.9m, our own guidance rather than the manufacturer's. That allows walking space and bedside tables on both sides. In a new build master bedroom, measure after accounting for wardrobes: rooms often feel smaller once furniture is in. Tighter than that, and the UK double may be the wiser buy.
Will standard king fitted sheets fit the Coolflex Hybrid CHILL king?
Possibly not. This mattress is 37cm deep, which is taller than many standard king fitted sheets are cut for. You'll need king sheets sized 150 x 200cm with a deep or extra-deep wall, so check the depth on your existing bedding before buying rather than after delivery day.