Firmness
Firm
Type
Hybrid
Depth (cm)
38
Number of Layers
7
Trial Period (nights)
100
Warranty (years)
10
Price Range
£478 to £568
Best Sleeping Position(s)
Certifications
Assessed from the specification published by Mattress Online, captured September 2026, and from regular price comparison across our UK retail partners.
The main draw here is the double spring system. The 2,000 full-size pocket springs are individually cased, which means each one responds to your body independently, giving support where you actually need it. The 2,000 mini springs above them add pressure relief and reduce motion transfer, useful if you share a bed with a restless partner. Heat is handled two ways: a Tencel knitted cover that wicks moisture, and a cool gel foam layer that allows more airflow than traditional memory foam. Add a pillow top for softness on the surface, and you get a mattress that is firm underneath but forgiving where you first lie down. The retailer-listed 10-year warranty adds reassurance, provided you register within 30 days.
Key Features & what's inside
- Tencel knitted cover. A soft knitted Tencel cover with antibacterial properties, which wicks away moisture to keep the sleep surface dry and cool. A sensible starting point if you tend to sleep warm.
- Microquilted layer. A traditionally microquilted layer that adds a touch of surface comfort. It gives the top of the mattress a gently cushioned, finished feel.
- Pillow top. An extra comfort layer for a more luxurious feel. This softens the first impression of what is otherwise a firm mattress.
- Gel Foam. A cool gel foam layer that allows greater airflow and reduces heat and moisture build-up compared with traditional memory foam. In practice, that means less of the clammy warmth some foam mattresses are known for.
- Foam comfort layer. A foam layer that helps distribute your weight evenly, which means a more balanced surface with fewer pressure points.
- Pocket springs. 2,000 full-size pocket springs made from durable steel, each individually cased in a cloth pocket. They react independently to movement, so support goes where your body needs it most.
- Mini pocket springs. A further 2,000 individually cased mini pocket springs providing added comfort and soothing pressure relief. They also help decrease motion transfer, so a partner's movements are less likely to disturb you.
Layer details from mattressonline.co.uk product page, September 2026.
Who's it NOT for?
This is a genuinely firm mattress, so lightweight side sleepers or anyone who likes a soft, cradling feel may find it too unyielding, pillow top or not. It's also heavy, which makes rotating it hard work. And there's no UK Single, so it won't suit a child's room or a spare single bed.
SleepSoul Space 4000 Pocket Orthopaedic Gel Mattress
How firm is the SleepSoul Space 4000?
It's rated firm. Owner feedback suggests it genuinely is, with some describing it as very firm. The pillow top and microquilted layers soften the surface, but underneath it's a supportive, solid feel best suited to back and front sleepers, or anyone who prefers plenty of pushback.
How many springs does the SleepSoul Space 4000 have?
4,000 in total: 2,000 full-size pocket springs and 2,000 mini pocket springs. Each spring is individually cased, which means they move independently, adapting support to your body and limiting how much you feel a partner's movements.
Does the SleepSoul Space 4000 come with a trial?
Mattress Online lists a 100-night trial with this mattress, but be aware it requires buying a mattress protector from them at the same time. This is the retailer's own offer rather than a SleepSoul policy, so terms may differ if you buy elsewhere.
Is the SleepSoul Space 4000 good for hot sleepers?
It has two features aimed at heat. The Tencel knitted cover wicks moisture to keep the surface dry and cool, and the gel foam layer allows greater airflow than traditional memory foam, reducing heat and moisture build-up. It's a reasonable pick if you tend to overheat on foam-heavy mattresses.
What warranty does the SleepSoul Space 4000 have?
The retailer listing states a 10-year warranty. One catch: it requires registering the product on the manufacturer's website within 30 days of purchase, so set a reminder once it arrives.
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