Sealy Immerse Hybrid Geltex 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
£839
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At 29cm deep, the Sealy Immerse Hybrid Geltex has a substantial, supportive feel that suits most back and combination sleepers. The price sits in the mid to upper range, although the certifications help justify it: Allergy UK approval, hypoallergenic fillings and a vegan friendly build. It comes in four UK sizes, from Single to Super King. If you tend to overheat at night, the gel foam and Tencel fibres are aimed squarely at you.
Mattress specifications
Firmness
Medium Firm
Type
Hybrid
Depth (cm)
29
Number of Layers
3
Trial Period (nights)
Warranty (years)
5
Price Range
£839 to £1,459
Best Sleeping Position(s)
Back Sleeping
Stomach Sleeping
Combination Sleeping
Certifications
BS 7177, Allergy UK
Assessed from the specification published by MattressNextDay, captured September 2026, and from regular price comparison across our UK retail partners.
Why should you choose this mattress?
Two things stand out here. First, temperature: Geltex is a gel-infused foam built for breathability, paired with naturally breathable Tencel fibres, which means warmth is drawn away rather than trapped against you, a genuine plus for hot sleepers. Second, allergy credentials: the mattress is hypoallergenic and carries the Allergy UK Seal of Approval, so it is a sensible pick if dust mites or sensitivities disturb your sleep. Underneath, 1400 pocket springs move independently, adapting to your shape and limiting the rock and roll you'd feel from a partner turning over. Sealy is an NBF-approved manufacturer, and the mattress is vegan friendly. Yes, the price sits in the mid to upper range, but the build depth and certifications back that up.
Key features & 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.
Best suited for?
Back sleepers
The 29cm depth and medium firm feel give a substantial, supportive surface, which suits lying on your back without sinking in too far.
Combination sleepers
Independently moving pocket springs adapt to your shape as you change position, so support follows you rather than pushing back as one block.
Warm sleepers
Gel-infused Geltex foam and naturally breathable Tencel fibres draw warmth away rather than trapping it against you, which helps if you tend to overheat at night.
Allergy sufferers
Hypoallergenic fillings and the Allergy UK Seal of Approval make this a sensible choice if dust mites or sensitivities disturb your sleep.
Couples
Each of the 1400 pocket springs sits in its own fabric pocket, which cuts down on the motion you feel when a partner turns over.
This is a medium firm mattress, so lightweight side sleepers may find it a little too solid to sink into properly, and anyone wanting a plush, cushioned surface should look elsewhere. Budget shoppers may also be put off by the starting price, and the retailer-stated guarantee is shorter than some brands offer.
Save on an earlier or ex-display model
Some retailers still sell the earlier version of this mattress, or ex-display and returned stock at a lower price. These are the sizes where it costs less than the current model's best price.
Sealy Immerse Hybrid Geltex Mattress
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FAQ's
How firm is the Sealy Immerse Hybrid Geltex mattress?
It's rated medium firm, a middle-of-the-road feel that suits most back and front sleepers. It offers enough give for combination sleepers too, although lighter side sleepers may find it slightly firm through the shoulders.
Is the Sealy Immerse Hybrid Geltex good for hot sleepers?
It's designed with hot sleepers in mind. The Geltex layer is a gel-infused foam built for breathability, and the Tencel fibres beneath it are naturally breathable, which means heat is less likely to build up than with traditional memory foam.
How many springs does the Sealy Immerse Hybrid Geltex have?
It contains 1400 pocket springs. Each one is housed in its own fabric pocket and works independently, so support follows the shape of your body and movement on one side of the bed is less likely to disturb the other.
What guarantee comes with the Sealy Immerse Hybrid Geltex?
MattressNextDay lists a 5-year guarantee alongside free next day delivery, with some addresses subject to a small fee. These are that retailer's stated terms, so it's sensible to confirm the guarantee and delivery details wherever you buy.
Is the Sealy Immerse Hybrid Geltex suitable for allergy sufferers?
Yes, on paper it's a strong choice. It's hypoallergenic, carries the Allergy UK Seal of Approval and is vegan friendly, while Sealy is an NBF-approved manufacturer, which gives some reassurance about the materials used inside.
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