Firmness
Type
Orthopaedic
Depth (cm)
38
Number of Layers
4
Trial Period (nights)
Warranty (years)
10
Price Range
£475 to £560
Best Sleeping Position(s)
Certifications
Assessed from the specification published by MattressNextDay, captured September 2026, and from regular price comparison across our UK retail partners.
This mattress suits you if you want firm support but worry about sleeping hot. The CoolGel foam layer is designed to prevent heat build-up, while individually pocketed springs work independently to support your spine, which means less of the roll-together you get on cheaper open-coil designs. A mini spring layer sits above the main springs for closer contouring, and the pillow top adds a softer surface feel. It's certified fire resistant to the BS7177: 2008 standard and carries a Which? Best Buy for double mattresses (January 2026). MattressNextDay lists a 10-year guarantee and free next day delivery to mainland UK, though some addresses may incur a small fee.
Key Features & what's inside
- Pillow Top. A generous layer of plush comfort filling that moulds to your body, which means the firm mattress beneath feels a little more forgiving on shoulders and hips. It's sewn on top, so you get pressure relief without losing the supportive base.
- CoolGel™ Foam. A thick layer of CoolGel foam that prevents heat build-up within the mattress while cradling your body. If you're a hot sleeper who's been put off memory foam before, this layer is doing the cooling work.
- Mini Springs. A layer of smaller springs that contours more closely to your body shape than full-size springs can. This helps relieve tension at each point of contact rather than supporting you in broad zones.
- Pocket Springs. Individually pocketed springs with a firm feel that work independently, targeting support where your body presses down most and helping keep your spine aligned. Because each spring moves on its own, a restless partner is less likely to disturb you.
Layer details from mattressnextday.co.uk product page, September 2026.
Who's it NOT for?
This is a firm mattress, so lightweight side sleepers may find it doesn't let their shoulders and hips sink in enough, even with the pillow top. There's no Single size listed, and no trial period is mentioned on the retailer page, so it's a less comfortable choice if you want to test before committing.
SleepSoul Space 4000 Orthopaedic CoolGel Mattress
How firm is the SleepSoul Space 4000 mattress?
It's rated firm. The pocket springs have a firm feel, softened slightly by the pillow top and CoolGel foam layers above. That combination suits back sleepers and anyone wanting orthopaedic-style support, although lighter side sleepers may find it a little too firm.
Does the SleepSoul Space 4000 come with a guarantee?
MattressNextDay lists a 10-year guarantee on its product page. Because that's a retailer listing rather than the brand's own site, it's sensible to confirm the guarantee terms with whichever retailer you buy from.
Is the SleepSoul Space 4000 good for hot sleepers?
It's designed with hot sleepers in mind. The CoolGel foam layer is there specifically to prevent heat build-up within the mattress, and the sprung construction allows more airflow than an all-foam design. It also has a knitted cover.
What sizes does the SleepSoul Space 4000 come in?
It's available in UK Double, King and Super King, priced from £475 to £560 depending on size. There's no Single option listed, which is a shame if you're buying for a child's room or a guest single.
How deep is the SleepSoul Space 4000 mattress?
It's 38cm deep, which is a genuinely substantial mattress. That extra height comes from stacking a pillow top, CoolGel foam and two spring layers. Do check your fitted sheets, as standard-depth sheets may struggle to stay on a mattress this tall.
Couldn't find an answer to your question? Send us a message