Sealy Immerse Hybrid Geltex King Size Mattress
The Sealy Immerse Hybrid Geltex is a medium firm hybrid mattress combining a 1400 pocket spring unit with Geltex, a gel-infused foam designed for pressure relief and breathability.
- Geltex & Tencel keep you cooler
- Allergy UK Seal of Approval
- Minimises partner disturbance
£1,129
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Sealy Immerse Hybrid Geltex Mattress
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Mattress details
Mattress
Sealy Immerse Hybrid Geltex Mattress
Size
Firmness
Medium Firm
Construction
Hybrid
Depth (cm)
29
Layers
3
Layer Details
Geltex® Memory Foam
A gel-infused foam that cradles your body for pressure relief while staying breathable, which means you get the contouring of memory foam with less of the heat build-up. It sits at the top, so this is the feel you'll notice first.
Tencel® Fibres
Soft, eco-friendly fibres that give the sleep surface a silky-smooth feel. They're naturally breathable, helping the mattress stay fresh and comfortable through the night.
1400 Pocket Springs
Each spring sits in its own fabric pocket and moves independently, which means support adjusts to your shoulders and hips rather than pushing back as one block. This also cuts down on motion transfer between partners.
Layer details from mattressnextday.co.uk product page, September 2026.
Key benefits
- Room to sleep apart, together: At 75cm each for two people sharing, you can both stretch out without negotiating territory in the small hours.
- Springs that keep movement local: The 1400 pocket springs move independently, which means an early riser slipping out at 5am is far less likely to wake the one still sleeping.
- Length for taller sleepers: At 200cm, the UK king adds 10cm of length over the UK double, so feet stay on the mattress rather than hanging off the end.
- Cooler across a shared bed: Two bodies generate real warmth, and the Geltex foam with Tencel fibres is designed to draw that heat away rather than trap it between you.
- Fits more rooms than you'd think: We suggest at least 2.7m x 2.9m, which many UK master bedrooms can manage even with wardrobes taking a wall.
This size suits you if...
You share the bed every night and a double has started to feel like a negotiation, or one of you keeps different hours and needs to get up without waking the other. The pocket springs help there, but the width does most of the work. It also suits couples where one partner is approaching 6ft, since the 200cm length is a genuine improvement over standard sizes.
Consider another size if...
Your bedroom is under our suggested 2.7m x 2.9m minimum, or you sleep alone. In either case we'd recommend the UK double instead, which needs a slightly smaller room at 2.6m x 2.8m.
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FAQ's
Is the Sealy Immerse Hybrid Geltex in a UK king good for couples?
It's a strong fit. The width gives you 75cm each for two people sharing, and the 1400 pocket springs move independently, so one person turning over sends far less movement across the bed. If your partner gets up hours before you, that combination of space and isolation makes a real difference.
What room size do I need for a UK king Sealy Immerse?
We suggest at least 2.7m x 2.9m, which leaves enough space to walk round the bed and open drawers. A room around 3.2m x 3.2m feels comfortable rather than tight. Measure with your wardrobes in place; a new build master bedroom can shrink quickly once the furniture is in.
How much bigger is the UK king than the UK double for this mattress?
The UK king is 15cm wider and 10cm longer than the UK double. The width is what couples notice night to night, while the length matters if either of you is tall. On a medium firm mattress like this, the extra space also means less drifting into each other's zone.
Is the UK king long enough for someone over 6ft?
Usually, yes. At 200cm, or 5ft x 6ft 6in in imperial, the UK king gives most tall sleepers clear space at the foot of the bed. If you're well over 6ft and want even more room, the UK super king is the same length but 30cm wider, so sizing up buys width rather than length.
Should I get the Sealy Immerse in a UK king or a UK super king?
The UK king suits most couples: plenty of space each without the room demands of the larger size. The UK super king is 30cm wider and needs a room of at least 3m x 2.9m, so it's the pick if your bedroom is generous and you want maximum separation, perhaps with a dog claiming its usual spot.