Silentnight Comfort Breathe 1200 King Size Mattress
The Silentnight Comfort Breathe 1200 is a medium/firm pocket sprung mattress with a breathability-first design.
- Breathable fibres for hot sleepers
- Minimises partner disturbance
- 60-night trial & 5-year guarantee
£599
Get the lowest price we've found
Save with the previous model
Some retailers still sell the earlier version of this mattress for less than the current model's best price.
Silentnight Comfort Breathe 1200 Mattress
More available sizes
Mattress details
Mattress
Silentnight Comfort Breathe 1200 Mattress
Size
Firmness
Medium Firm
Construction
Foam
Pocket Spring
Memory Foam
Depth (cm)
25
Layers
5
Layer Details
Sleep surface
A naturally hypoallergenic fabric surface that's soft against the skin. A sensible choice if allergies or sensitive skin are a concern.
Comfort Breathe®
Silentnight says these fibres are 15x more breathable than standard memory foam, promoting airflow and regulating temperature. In practice, that means less overnight heat build-up, which hot sleepers will appreciate.
1200 Mirapocket spring unit
1200 pocket springs respond individually to your body's movements, which means support where you need it rather than a one-size-fits-all push-back. The zoning is designed to aid spinal alignment, helpful if back or neck pain is part of your mornings.
Protective Layer
This layer spreads pressure from the spring unit across the mattress, which means less localised wear over time. It's there for longevity rather than feel.
Durable case
A soft but hard-wearing outer case designed to keep the mattress comfortable for years. Unglamorous, but it matters for how the mattress ages.
Layer details from silentnight.co.uk product page, September 2026.
Key benefits
- 75cm each, every night: With 75cm each for two people sharing, you can both turn over without negotiating, a difference you notice most on restless nights.
- Movement stays on your side: The 1200 Mirapocket springs respond individually, so a partner getting up hours before you is less likely to wake you, and the wider bed helps further.
- Length for taller sleepers: At 200cm, the UK king is 10cm longer than the UK double, which stops feet hanging off the end for anyone approaching six foot.
- Cooler across a bigger surface: The Comfort Breathe fibre layer promotes airflow rather than trapping heat, and with more space between you there's less shared body warmth to begin with.
- Fits a normal master bedroom: We suggest allowing at least 2.7m x 2.9m, which most UK master bedrooms manage, unlike the roomier demands of a UK super king.
This size suits you if...
You share the bed every night and a double has started to feel cramped, especially if one of you gets up much earlier than the other and you want movement, and space, kept to your own side. It also fits if either of you is approaching six foot and needs the 200cm length, or if a dog has quietly claimed a corner of the bed and you'd like your share back.
Consider another size if...
Your bedroom is under our suggested 2.7m x 2.9m minimum, or you mostly sleep alone. We'd recommend the UK double instead, which needs a room of at least 2.6m x 2.8m and still sleeps two.
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.
FAQ's
Is the Silentnight Comfort Breathe 1200 UK king good for couples?
Yes, and it's arguably the size this mattress makes most sense in. The 1200 pocket springs move independently, so one of you shifting or getting up early transfers less across the mattress, and with 75cm each for two people sharing you're less likely to feel it at all. Restless pairs and mismatched schedules are exactly who it suits.
What room size do I need for the Comfort Breathe 1200 in a UK king?
We suggest allowing at least 2.7m x 2.9m, which leaves room to walk round both sides and open drawers without shuffling sideways. That's our guidance rather than Silentnight's. New build master bedrooms can feel smaller than the floor plan suggests once wardrobes go in, so measure the usable space, not the room.
How much bigger is the UK king than the double for this mattress?
The UK king is 15cm wider and 10cm longer than the UK double. The width is what couples feel night to night, but the length matters too: at 200cm, it takes the pressure off anyone approaching six foot who currently sleeps diagonally to fit. The feel and construction are identical in both sizes.
Is the Silentnight Comfort Breathe 1200 UK king long enough for tall sleepers?
At 200cm (the full size is 5ft x 6ft 6in), it gives most tall sleepers comfortable clearance, and it's 10cm longer than the UK double. If one of you is well over six foot and length is the whole reason you're upgrading, the UK super king is the same length, so sizing up only buys width, not extra legroom.
Should I get the UK king or UK super king in this mattress?
The UK super king is 30cm wider than the UK king but the same length, and we suggest a room of at least 3m x 2.9m for it. If your bedroom is average sized, the UK king is the safer call: you keep the pocket sprung motion isolation and the 200cm length without squeezing the room. Compare the retailers listed on this page for both.