Horizon is one of Mattress Online's own sub-brands, launched in 2018 to fill a gap in their catalogue for affordable pocket spring mattresses with thick memory foam comfort layers. The range is small and focused. Pocket springs underneath, graphite-infused memory foam on top, and a travel-inspired naming scheme (Adventurer, Voyager) that gives the brand a cleaner identity than most retailer exclusives manage. I've pressed into a couple of Horizon models in-store and the graphite memory foam does feel different from standard foam. Cooler on first contact, slower to warm up, though whether that holds across a full night is something I'd need a sleep test to confirm.
The brand doesn't try to be everything. It targets buyers who want the pressure-relieving feel of memory foam paired with proper pocket spring support, at a price that sits below the mainstream D2C hybrids. For that specific brief, the range delivers.
The Adventurer 1000
The Adventurer 1000 Pocket Memory is the model that carries the range and the one Which? has reviewed independently. A 3cm graphite-infused memory foam layer sits over 1000 individually pocketed springs. Pressure relief from the foam at the surface. Structural support from the springs underneath. The two layers work separately and you can feel both when you lie down. Medium to firm on the firmness scale. The knitted cover adds breathability at the surface, and the edge construction is reinforced for full edge-to-edge support, which is something most budget pocket sprung mattresses skip entirely.
The graphite infusion is the spec detail that separates the Adventurer from a standard memory foam hybrid. Graphite disperses heat faster than regular memory foam, so the surface stays cooler during the initial settling period when you first lie down. It's a more credible cooling mechanism than the vague "cooling gel" claims you see on budget brands, though it still won't match the airflow of a natural fibre or latex comfort layer over the full night.
What I Found in the Showroom
When I pressed into the memory foam on the Horizon Pocket Memory, it had that slow, sink-in response you get from proper memory foam rather than the bouncy pushback of a latex or pocket-spring-only build. The foam holds your shape for a moment before releasing. Side sleepers who want cushioning at the shoulder and hip will appreciate that, but buyers who prefer a faster-responding surface will find it too slow. I noticed the edges dipped a bit more than I'd expect from a reinforced-edge model, though Mattress Online's spec sheet claims edge-to-edge support. Might be a display model wear issue, might be the construction. Can't be sure from one visit.
Heat was the other observation. Thicker memory foam layers hold onto body warmth, and the Horizon's 3cm graphite layer is deep enough to notice. The graphite does its cooling job on first contact, but after twenty minutes the warmth builds in the way it does with any foam-heavy comfort layer. Hot sleepers should weigh that trade-off before committing.
Where to Buy and Trial Terms
Horizon sells primarily through Mattress Online, which carries the full range with a 60-night comfort trial and free delivery. The Adventurer also appears at B&Q and BedBoy for buyers who prefer ordering through those channels. Pricing is consistent across stockists because Mattress Online controls the brand.
The 60-night trial is standard for Mattress Online exclusives but shorter than the 100-365 night trials from the D2C competition. If trial length is a priority, Simba, Emma or Nectar give you more decision time. If you're confident from the spec and the Mattress Online reviews, 60 nights is enough to confirm the feel.
Who Horizon Suits
Back sleepers and side sleepers of average weight who want pressure-relieving memory foam over a pocket spring base at a price below the mainstream D2C hybrids. The Adventurer 1000 hits that buyer profile cleanly.
Budget-conscious buyers who want proper pocket spring construction with a foam comfort layer. At its price tier, the Horizon offers more spring support than pure foam alternatives costing about the same.
Who It Doesn't
Hot sleepers. The graphite foam helps but doesn't solve the heat issue the way a natural fibre or latex comfort layer would. If sleeping cool is the priority, look at natural fibre brands or the D2C hybrids with dedicated cooling specs.
Buyers who want a long trial. Sixty nights through Mattress Online is the ceiling, and there's no extending it. The D2C rivals give you 100-365 nights.
Anyone who dislikes the slow memory foam feel. If you've tried memory foam before and found the sinking sensation uncomfortable or claustrophobic, Horizon won't change your mind. The foam layer is thick enough that it defines the surface feel.
Verdict
Horizon is a focused, honest sub-brand from Mattress Online that does one thing well: affordable pocket spring mattresses with thick graphite-infused memory foam on top. The Adventurer 1000 is the model to look at. The range is small, the pricing is fair, and the Which? review gives it independent credibility most retailer exclusives don't have. Not the brand for hot sleepers or long-trial seekers, but for buyers who know they want memory foam over pocket springs at a mid-market price, Horizon delivers.
