Firmness
Type
Open Coil Spring
Depth (cm)
29
Number of Layers
3
Trial Period (nights)
Warranty (years)
5
Price Range
£389 to £679
Best Sleeping Position(s)
Certifications
Assessed from the specification published by MattressNextDay, captured September 2026, and from regular price comparison across our UK retail partners.
The main draw here is proper firm support at a sensible price. The PostureTech CS springs are twice tempered, which means they've been heat-treated twice to hold their shape for longer, and the listing describes a PowerPack in the centre of the mattress for extra lumbar support. EdgeGuard, a high-density foam strip lining the springs, firms up the edges so you can sit or sleep near the side without that roll-off feeling. Being double-sided is rarer these days, and it genuinely extends the life of a mattress if you're willing to turn it. Yes, the fillings are polyester rather than natural fibres, but polyester recovers well and keeps the price down.
Key Features & what's inside
- Cover. A breathable Belgian damask fabric cover, which means air can move through the sleep surface rather than getting trapped. That helps if you tend to run warm at night.
- Comfort Fillings. 100% polyester fillings that offer good recovery and durability. In practice that means the comfort layer springs back into shape rather than developing body impressions quickly.
- Support System. PostureTech CS springs respond to your body weight, targeting key areas to give deep-down support where you need it most. The springs are twice tempered, a heat treatment that helps them keep their tension over time.
Layer details from mattressnextday.co.uk product page, September 2026.
Who's it NOT for?
This is a firm mattress, so lightweight side sleepers may find it a little too unyielding on the shoulders and hips. If you prefer the slow, cradling feel of memory foam, a traditional sprung mattress like this won't give you that. And if you'd rather never flip a mattress, its double-sided design loses some of its point.
Sealy Ortho Plus Gold Mattress
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Is the Sealy Ortho Plus Gold mattress firm?
Yes, Sealy rates it as firm. The PostureTech CS springs give deep-down support that responds to your body weight, and the listing describes a central PowerPack for added lumbar support. It suits back and front sleepers best, although lightweight side sleepers may find it slightly too firm.
Can you flip the Sealy Ortho Plus Gold mattress?
Yes, it's a double-sided, turnable design, which is increasingly uncommon. Flipping it regularly helps the fillings wear evenly, so it should stay comfortable for longer than a one-sided equivalent. It's also hand-tufted, which holds the fillings in place.
How deep is the Sealy Ortho Plus Gold mattress?
It's 29cm deep, so standard fitted sheets should fit without trouble. The height comes from polyester comfort fillings and soft white fibres over the PostureTech CS spring support system, all wrapped in a Belgian damask cover.
What guarantee does the Sealy Ortho Plus Gold come with?
The MattressNextDay listing states a Sealy 5 year guarantee. No sleep trial is mentioned on the page, so check returns terms with your retailer before you buy. MattressNextDay also lists free next day delivery to mainland UK, though some addresses may incur a small fee.
What sizes does the Sealy Ortho Plus Gold come in?
Five UK sizes: Single, Small Double, Double, King and Super King. Prices range from £389 to £679 depending on the size you choose, which is reasonable for a hand-tufted, double-sided sprung mattress from an NBF-Approved Manufacturer.
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