Silentnight Healthy Growth Cosmo Eco Mattress
The Silentnight Healthy Growth Cosmo Eco is a single-size mattress built around an open coil spring system, which means a traditional, slightly bouncy feel with a Medium/Firm rating.
- Foam-free & hypoallergenic
- Medium-firm feel suits growing sleepers
- 60-night trial & 5-year guarantee
£259
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Above the springs in the Silentnight Healthy Growth Cosmo Eco sit breathable EcoComfort Fibres and an airflow border, so heat can move away from the body rather than building up under a sleeper. It's free from foam and FR chemical treatments and rated hypoallergenic, which will reassure parents choosing for a growing child. At 23cm deep, it's a straightforward option rather than a luxury one, and Silentnight backs it with a 60-night trial and a 5-year guarantee.
Mattress specifications
Firmness
Medium Firm
Type
Eco-Friendly Mattress
Depth (cm)
23
Number of Layers
3
Trial Period (nights)
60
Warranty (years)
5
Price Range
£259
Best Sleeping Position(s)
Back Sleeping
Stomach Sleeping
Combination Sleeping
Certifications
Assessed from Silentnight's published specification for this mattress, captured September 2026, and from regular price comparison across our UK retail partners.
Why should you choose this mattress?
The main draw is what's left out. There's no foam and no FR chemical treatment, and the mattress is hypoallergenic, which matters if you're buying for a child or anyone with sensitivities. The EcoComfort Fibres comfort layer is breathable and paired with an airflow border, so hot sleepers should stay a little cooler than on a dense foam design. The Medium/Firm open coil support suits most growing sleepers, although anyone wanting a soft, cradling feel should look elsewhere. It sits at an accessible price, and the 60-night trial gives you room to change your mind. Delivery is quoted at 14 days, so allow a little lead time.
Key features & layer details
Sleep surface
A quilted sleep surface fabric, which gives a soft, cushioned first touch before you reach the support beneath. Silentnight describes it as sumptuous, though the overall feel remains Medium/Firm.
Comfort layer
Breathable EcoComfort Fibres with an airflow border, which means air can circulate through the mattress rather than trapping warmth. A sensible choice for children, who often sleep warm.
Support system
An open coil traditional spring system with interconnected springs. Because the springs are linked, the whole surface responds together, giving an even, slightly bouncy Medium/Firm support.
Layer details from silentnight.co.uk product page, September 2026.
Best suited for?
Children
Free from foam and FR chemical treatments and rated hypoallergenic, this mattress gives parents a simple, reassuring choice for a growing child's bed.
Allergy sufferers
The hypoallergenic rating and the lack of foam and FR chemical treatments suit anyone with sensitivities who wants a plainer, cleaner mattress.
Warm sleepers
Breathable EcoComfort Fibres and an airflow border let air circulate through the mattress, so heat moves away rather than building up overnight.
Eco-conscious buyers
Leaving out foam and FR chemical treatments, and using EcoComfort Fibres in the comfort layer, gives a simpler build for those wanting less in their mattress.
Teenagers
The Medium/Firm open coil support responds evenly across the surface, which suits growing sleepers who want a supportive feel with a little bounce.
It's only available as a UK Single, so couples and anyone wanting a double or larger will need to look elsewhere. The interconnected open coil springs don't contour to the body the way pocket springs or foam do, so if you want pressure relief for a heavier adult side sleeper, this simple design may feel a little too firm.
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.
Silentnight Healthy Growth Cosmo Eco Mattress
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FAQ's
How firm is the Silentnight Healthy Growth Cosmo Eco mattress?
Silentnight rates it Medium/Firm. That means a supportive, fairly solid feel with a quilted sleep surface adding some initial softness, which suits most back and front sleepers, although lightweight side sleepers may find it slightly firm.
Does the Silentnight Healthy Growth Cosmo Eco have a trial and guarantee?
Yes. Silentnight offers a 60-night trial and a 5-year guarantee on this mattress, so you can try it at home and return it if it doesn't suit.
Is the Silentnight Healthy Growth Cosmo Eco suitable for allergy sufferers?
It's rated hypoallergenic and is free from foam and FR chemical treatments, which makes it a reassuring choice for children or anyone sensitive to allergens or chemical finishes.
What sizes does the Silentnight Healthy Growth Cosmo Eco come in?
It's currently available in UK Single only, at 23cm deep. There are no double or king options listed.
How long does delivery take for the Silentnight Healthy Growth Cosmo Eco?
Silentnight's product page quotes delivery within 14 days, so it isn't a next-day option. Worth planning ahead if you need it for a set date.
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