Silentnight Healthy Growth Comet Eco Comfort Miracoil Mattress
Mattress
Silentnight Healthy Growth Comet Eco Comfort Miracoil Mattress
Size
Firmness
Construction
Depth (cm)
21
Layers
3
Layer Details
- Sleep surface. A luxurious quilted sleep surface sits on top, which means the first thing your child feels is a soft, cushioned finish. It adds an extra touch of comfort above the firmer layers beneath.
- EcoComfort Fibres. Beneath the surface, breathable EcoComfort Fibres™ soothe and help maintain a comfortable temperature through the night. If your child is a warm sleeper, this is the layer doing the quiet work.
- Support system. At the base, Miracoil® springs provide zoned support, scientifically proven by Silentnight to improve spinal alignment and posture. In practice, that means the hips and shoulders are held in a healthier position as your child grows.
Layer details from silentnight.co.uk product page, September 2026.
- Fits the smallest bedrooms: At 90cm wide, it slots into a compact child's room while still leaving a walkway, and we suggest a floor space of at least 2.1m x 2.8m.
- Works with raised frames: The 21cm depth suits bunks, cabin beds and mid sleepers, where a taller adult mattress can sit above the safety rail.
- Two beds, one room: Siblings sharing a room can usually fit two UK singles with space to move between them, which a small double rarely allows.
- Cheap, easy bedding: Single sheets and duvets are the most widely stocked bedding in the UK, so replacing outgrown or worn sets costs little.
- Support sized for one growing sleeper: The Miracoil® zoned springs give steady Medium/Firm support across the full 90cm width, which suits lighter bodies through the years posture is still developing.
This size suits you if...
You're buying for a child or teenager moving to their first full-size bed, or furnishing a bunk, cabin or mid sleeper where a slimmer 21cm mattress sits safely below the rail. It also suits a spare room that doubles as an office, or a student heading to halls where the frame is provided and the mattress isn't.
Consider another size if...
You need to sleep two people, or you want a soft, sink-in feel as a single adult. This mattress is only made in a UK single, so a couple would need a different model in a UK double or larger.
Similar Mattresses in This Price Range
Did you know? On Mattress Unboxed we have over 1,000 different mattresses to suit all types of sleepers. View all mattresses.
Will the Healthy Growth Comet UK single fit a bunk bed?
Yes, in most cases. The UK single is the standard bunk and mid sleeper size at 90 x 190cm, and this mattress's 21cm depth is slimmer than many adult designs, so it's less likely to rise above the safety rail. Check your frame's maximum mattress depth before ordering, as some bunks specify a lower limit.
What room size do I need for the Healthy Growth Comet single?
We suggest allowing at least 2.1m x 2.8m of floor space for a UK single. That leaves room to walk around the bed and open drawers or wardrobe doors, which matters in a child's room where toy storage and a desk are usually fighting for the same square metres.
Can two Healthy Growth Comet singles fit in a shared kids' room?
Often, yes. Two UK singles at 90cm wide each will fit in many shared bedrooms with a walkway between them, and each child gets their own zoned Miracoil® support rather than sharing a surface. Measure your room against two mattress footprints of 90 x 190cm plus space to move before committing.
How long is the Silentnight Healthy Growth Comet single?
It's 190cm long, or 3ft x 6ft 3in in imperial. That's the standard UK single length, so a teenager has room to grow into it, and it fits any standard single frame, divan or bunk without overhang. Standard single fitted sheets and a 135 x 200cm single duvet fit it.
Is a UK single big enough for a teenager?
For most, yes. At 90 x 190cm it's the standard size for teens right through to adulthood, and the Medium/Firm feel suits lighter, growing bodies. A particularly tall or restless teenager might eventually want more width, but as this mattress only comes in a UK single, that would mean a different model.