Sealy Duchess Contract Mattress
The Sealy Duchess Contract is a medium firm sprung mattress with a quilted surface, available in UK Single, Double, King and Super King sizes.
- Suits most back & combination sleepers
- Usable space right to the edges
- 5-year guarantee
£599
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The Sealy Duchess Contract has Sealy's PostureTech Core Support spring system at its core, which means the springs get gradually firmer as you press into them, so you feel gentle cushioning at first and deeper support where your weight settles. EdgeGuard reinforcement runs around the border, which means you can sleep closer to the edge without that rolling-off feeling. It's a double-sided design that needs turning regularly, more effort than a no-turn mattress, but flipping tends to help a mattress wear evenly over the years.
Mattress specifications
Firmness
Medium Firm
Type
Foam
Depth (cm)
26
Number of Layers
4
Trial Period (nights)
Warranty (years)
5
Price Range
£599 to £999
Best Sleeping Position(s)
Back Sleeping
Stomach Sleeping
Combination Sleeping
Certifications
Assessed from Sealy'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 Duchess suits sleepers who want a traditional, supportive feel rather than the deep sink of memory foam. Layers of Sealy medium foam over the PostureTech springs give a balance of cushioning and pushback, which means most back and combination sleepers should feel held rather than swallowed. The EdgeGuard border adds durability and edge-to-edge support, useful if you share a bed and use the full width. It comes with a 5 year guarantee, and a BugShield treatment on the fabric. It sits in sensible mid-market territory for a sprung Sealy, though you'll need to be happy turning it regularly to keep it wearing well.
Key features & layer details
Quilted Surface
A quilted sleep surface sits on top, which means a soft, slightly cushioned first impression when you lie down. It's a traditional finish rather than a plush pillow-top feel.
Sealy Medium Foam
Generous layers of Sealy medium foam add comfort between you and the springs. This is what softens the medium firm support so it doesn't feel hard at the surface.
PostureTech Core Support Springs
The PostureTech Core Support system uses springs that gradually get firmer as pressure increases, which means heavier areas like your hips get deeper support while lighter areas rest more gently. The result is pressure relief without sagging.
EdgeGuard
EdgeGuard reinforces the perimeter for added durability and edge-to-edge support. In practice, that gives you more usable sleeping space right up to the sides.
Layer details from sealy.co.uk product page, September 2026.
Best suited for?
Back sleepers
PostureTech springs get firmer as you press into them, which means your hips get deeper support while the medium foam layers keep your back held rather than swallowed.
Combination sleepers
Medium foam over responsive springs gives a balance of cushioning and pushback, which means changing position through the night feels easy rather than like climbing out of a hollow.
Couples
EdgeGuard reinforcement around the border gives edge-to-edge support, which means both of you can use the full width without that rolling-off feeling near the sides.
Heavier sleepers
Springs that grow firmer under pressure give deeper support where your weight settles, while the medium firm feel and 26cm depth help the bed resist sagging.
Guest rooms
A traditional, supportive medium firm feel suits most visitors, and the 5 year guarantee and BugShield fabric treatment add reassurance for a bed that sees occasional use.
If you want a no-turn mattress, look elsewhere: this is double-sided and needs turning regularly. If you prefer that slow-sinking memory foam hug, this might not be the best choice, as the medium foam and springs give a more traditional, responsive feel. Lightweight side sleepers may find medium firm slightly 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.
Sealy Duchess Contract Mattress
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FAQ's
How firm is the Sealy Duchess Contract mattress?
It's listed as medium firm, a supportive feel that suits most back and front sleepers. The Sealy medium foam layers soften the surface, but lightweight side sleepers who need more give at the shoulder may find it a little too firm.
Do you need to turn the Sealy Duchess Contract mattress?
Yes. Sealy's page indicates this is a double-sided mattress that should be turned regularly. It's a small chore, but turning helps the comfort layers wear evenly on both sides over time.
How deep is the Sealy Duchess Contract mattress?
Sealy's product description states the depth is 26cm, although the technical specifications on the same page list 32cm for all sizes. If exact depth matters for your fitted sheets or bed frame, it's sensible to confirm with the retailer before ordering.
What guarantee comes with the Sealy Duchess Contract?
Sealy's own site states a 5-year guarantee, and the retailer listing shows the same 5-year cover. As always, check the terms at your chosen retailer before you buy.
What sizes does the Sealy Duchess Contract come in?
It's available in UK Single, Double, King and Super King.
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