Silentnight Healthy Growth Comet Eco Miracoil Mattress
The Silentnight Healthy Growth Comet Eco is a medium/firm mattress designed with growing sleepers in mind, available in a UK Single.
- Zoned support as your child grows
- Foam-free with no chemical treatments
- 60-night trial & 5-year guarantee
£219
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The Silentnight Healthy Growth Comet Eco pairs Miracoil® springs, a zoned support system, with breathable EcoComfort Fibres™ that help keep the sleep surface cooler through the night. At 21cm deep it's slimmer than many adult mattresses, which suits children's bed frames and bunk beds well. It's hypoallergenic, naturally resistant to allergens, and made without foam or FR chemical treatments, a genuine reassurance if you're cautious about what your child sleeps on. Silentnight backs it with a 60-night trial and a 5-year guarantee.
Mattress specifications
Firmness
Medium Firm
Type
Eco-Friendly Mattress
Depth (cm)
21
Number of Layers
3
Trial Period (nights)
60
Warranty (years)
5
Price Range
£219
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 strongest reason to choose this mattress is the combination of proper zoned support and a clean-sheet approach to materials. The Miracoil® spring system is scientifically proven to improve spinal alignment and posture, which matters during the years a child's back is still developing. The EcoComfort Fibres™ layer is breathable, so a warm sleeper should feel a little less clammy than on a dense foam alternative. Being foam free and FR chemical treatment free is rare at the affordable end, and it sits there without feeling flimsy. Add the 60-night trial and 5-year guarantee from Silentnight, and there's room to change your mind.
Key features & layer details
Sleep surface
A luxurious quilted sleep surface that adds an extra touch of comfort. You'll feel a soft, gently cushioned finish rather than sleeping directly on the firmer layers below.
EcoComfort Fibres
Breathable EcoComfort Fibres™ that allow air to move through the comfort layer. In practice this means cooler sleep, useful for children who tend to overheat at night.
Support system
Miracoil® springs offering zoned support, scientifically proven to improve spinal alignment and posture. The zoning gives more resistance where body weight concentrates, keeping the spine in a healthier position.
Layer details from silentnight.co.uk product page, September 2026.
Best suited for?
Children
Made with children's beds in mind, its zoned Miracoil springs and medium firm feel give growing sleepers a supportive surface without any foam.
Bunk beds
At 21cm deep it is slimmer than many adult mattresses, so it sits comfortably in bunk bed frames where a thicker mattress would reduce safe clearance.
Warm sleepers
Breathable EcoComfort Fibres let air move through the comfort layer, which means less clamminess than you would expect from a dense foam mattress.
Allergy sufferers
Being hypoallergenic and naturally resistant to allergens, with no foam or FR chemical treatments, it suits anyone wanting a cleaner sleep surface.
Eco-conscious buyers
Anyone wary of what a mattress is made from will like the foam free build and the absence of FR chemical treatments.
It's only made in a UK Single, so it won't work for couples or anyone wanting a double upwards. The medium/firm feel may be slightly too solid for very lightweight side sleepers, and at 21cm deep it will sit lower in the frame than a chunkier adult mattress. If you want memory foam contouring, this foam-free design isn't it.
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 Comet Eco Miracoil Mattress
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FAQ's
How firm is the Silentnight Healthy Growth Comet Eco mattress?
Silentnight describes it as medium/firm. That means a supportive, fairly solid feel with a quilted sleep surface softening the top, which suits most back and front sleepers, although lightweight side sleepers may find it a little too firm.
Does the Silentnight Comet Eco mattress contain foam?
No. It's built from EcoComfort Fibres™ over Miracoil® springs, with no foam and no FR chemical treatments. It's also hypoallergenic and naturally resistant to allergens, a sensible choice if your child has sensitivities.
What sizes does the Silentnight Healthy Growth Comet Eco come in?
It's available in a UK Single only. There's no double or king option, so it's aimed squarely at single beds, and its 21cm depth works well on children's frames and bunk beds.
Is there a trial period on the Silentnight Comet Eco?
Yes. Silentnight offers a 60-night trial on this mattress, alongside a 5-year guarantee, so you have time to see how your child settles on it before committing.
How long does delivery take for the Silentnight Comet Eco?
Silentnight lists delivery at 14 days for this mattress.
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