Sealy Immerse Hybrid Geltex Single 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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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
- Fits where space is tight: At 90cm wide, this mattress leaves room for a desk, wardrobe and toy storage in a child's bedroom, or a workspace in a spare room that doubles as an office.
- A hybrid build children can grow into: The 1400 pocket springs and Geltex foam suit a teenager through to adulthood, so you're less likely to be replacing it in a couple of years.
- Cool for small, warm rooms: Box rooms and loft spaces heat up quickly, and the breathable gel foam and Tencel fibres draw warmth away rather than trapping it.
- Allergy credentials for a child's bed: Hypoallergenic fillings and Allergy UK approval matter most in kids' rooms, where dust sensitivities often first show up.
- Cheap, easy bedding: Standard single sheets and a 135 x 200cm duvet fit, the most widely stocked and lowest-cost bedding of any UK size.
This size suits you if...
You're buying for a child or teenager and want a mattress that will still support them as they grow, you sleep alone in a compact room where every centimetre of floor space counts, or you're kitting out a spare room that has to work as an office too. It also suits a student room or first flat where the frame is provided but the mattress isn't.
Consider another size if...
You're an adult who spreads out in the night, or you sometimes share the bed. The UK double, 45cm wider and the same length, would suit you better; allow at least 2.6m x 2.8m of floor space for it.
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FAQ's
Is the Sealy Immerse Hybrid Geltex UK single suitable for a bunk or mid sleeper frame?
Check your frame first. This mattress is 29cm deep, which is on the substantial side for raised frames, where safety rails need to sit well above the mattress surface. Measure from the base to the top of the rail and compare it with the frame maker's stated maximum depth before you order.
Will the UK single fit under a sloped loft ceiling?
Often, yes. At 90cm wide and 190cm long, a UK single is the easiest full-length mattress to place under an eave, since you can push it against the low side and keep standing height where you get in and out. Just check you have at least 2.1m x 2.8m of usable floor.
Is a UK single big enough for an adult in a spare room?
For occasional guests, yes. At 3ft wide it's the standard one-person size, and the medium firm hybrid build supports adult weight comfortably for a night or two. For a guest room used regularly by couples, or by anyone who likes to sprawl, the UK double at 45cm wider is the safer choice.
Can two Sealy Immerse UK singles work for siblings sharing a room?
That's a common setup, and the 90cm width makes it workable: two singles plus a walkway need less wall space than you might expect. Because each mattress has its own 1400 independent pocket springs, one child fidgeting won't disturb the other. Measure your room against a 2.1m x 2.8m minimum per bed area.
How much smaller is the UK single than the UK king?
The UK single is 60cm narrower than the UK king and 10cm shorter, so the difference is considerable. If you're a solo adult sleeper with space to spare, the UK king gives you room to stretch out, and we suggest allowing at least 2.7m x 2.9m of floor space for it.