Why our sleep experts loved it
The Diamond Spring Free Deluxe Mattress is one of those products that looks, on paper, like it’s been built to win a comparison chart. It’s the “new-store-only” Emma range (available through Furniture Village), it’s packed with branded foam layers, it leans hard into cooling claims, and it comes with the kind of consumer-friendly safety net that modern mattress shoppers expect: a 200-night trial and a long 20-year guarantee. I tested this mattress in store, in person, spending proper time on it in a few sleeping positions and paying attention to the things that usually get glossed over in a quick showroom bounce, like surface temperature, initial pressure relief, how quickly the foams respond, and how “dead” or “lively” the bed feels under movement. I did not take it home, so I can’t claim what it’s like on night twelve, or during a heatwave, or after a few months of compression. What I can do is tell you exactly how it felt to me in the showroom, how its construction is likely to behave over time based on a decade in the industry, and who I think should and absolutely should not buy it.
Here’s my blunt take upfront: this is a firm, foam-based mattress that feels supportive and impressively “put together”, but I’m sceptical about the extent of the cooling story. It’s still foam, it still has that gentle heat-holding character, and while the cover gives you a pleasing cool touch at first contact, I don’t think it transforms the experience into anything close to a naturally breathable sprung mattress. If you’re a back sleeper who wants a firm, stable surface and doesn’t want the bounce or motion of springs, this is a serious option. If you’re a side sleeper, particularly with an hourglass shape or prominent hips and shoulders, I’d steer you away without hesitation.
Design and features
The Diamond Spring Free Deluxe is a 29cm deep foam mattress, and it’s unashamedly positioned as a premium-feeling, tech-forward model. In-store, it looks smart and contemporary, with the sort of clean, “new generation” finish Emma tends to do well. The standout design feature is the PolarLuxe ultra cooling cover. The first thing I noticed when I put my hand on it was that it does have that initial cool-to-the-touch sensation, the kind you often get from modern performance fabrics that are engineered to feel refreshing on contact. That can be genuinely pleasant, especially if you’re someone who gets into bed already warm and wants that first wave of relief.
However, I’m going to be slightly cynical here, because I’ve tested a lot of “cool touch” covers and they nearly all behave the same way: they feel cold for a short period, then they equalise to your body temperature. That doesn’t make them pointless, but it does mean they’re not a magic wand. They’re a comfort feature, not an air-conditioning unit. The cover is removable and washable up to 40°C, which I love in principle because hygiene matters, and it’s one of the easiest ways to keep a mattress feeling fresher for longer. Just be realistic: most people don’t actually wash their mattress cover often, and if you use a mattress protector (which you should), you may never need to remove it unless there’s a spill or allergy concern. Still, it’s a genuine plus, particularly for households with pets, kids, or anyone prone to night sweats.
Construction-wise, the story is layered foams with branding that tries to explain the “why” behind each layer. You’ve got a Diamond Cool visco-elastic foam with graphite particles intended to move excess heat away, then HRXComfort foam designed to let you sink in without losing support, and then HRXSupport foam, which is the structural workhorse and is described as precision-engineered to keep its shape for 10 years. That’s an important point because one of the main criticisms of all-foam mattresses, especially firmer ones, is that they can feel fantastic at first but soften unevenly or develop body impressions if the base foam isn’t up to it. The fact Emma is making a point of shape retention suggests they’re trying to tackle that perception head-on.
The mattress has an anti-slip bottom cover, which sounds like a small detail until you’ve tried a foam mattress on a smooth platform base and found it creeping out of position over time. In store, it looked like the underside had real grip. It won’t fix a poor bed base, but it can reduce the annoying “mattress migration” you sometimes see with heavier foam constructions. Practical care-wise, you don’t need to turn it, but you should rotate it regularly. That’s sensible, and I always recommend rotation for any one-sided mattress because it helps even out the stress placed on the comfort layers.
One technical note that matters more than most people realise: if you use it on a slatted base, the slat gaps must be no wider than 7.5cm, or you risk excess dipping and potentially invalidating the guarantee. This isn’t Emma being difficult; it’s simply that foam needs proper, consistent support underneath. If you’ve got an old frame with wide gaps, this mattress may feel softer than intended, and long-term it can fatigue faster. If you’re investing in a mattress at this level, pair it with a suitable base so you’re not sabotaging the performance from day one.
Mattress comfort
In-store, the immediate impression is “firm means firm”. Some mattresses described as firm are actually what I’d call medium-firm, because brands don’t want to scare customers off. This one doesn’t play that game. The Diamond Spring Free Deluxe has a noticeably firmer tension the moment you settle your weight into it. There is a comfort layer feel, so it’s not like lying on a board, but it doesn’t give you that slow, deep, melting cradle that many people associate with memory foam. Instead, it’s more of a controlled, contained sink, then you meet the resistance of the support foam fairly quickly.
The HRXComfort layer is clearly doing something because you can “snuggle in” a little, especially at the shoulder and hip when you test it on your side. But here’s the key: it doesn’t sink enough for many side sleepers. When I lay on my side in store, I could feel the beginnings of pressure building around the shoulder area, and I could also feel that my hip wasn’t dropping quite far enough to keep my spine neutrally aligned. Over a full night, that’s the sort of thing that turns into numb arms, a tight lower back, or the feeling that you keep needing to change position to get comfortable. Side sleepers are often told they need softness, but it’s not really softness they need, it’s proportional sinkage in the right zones. This mattress is more about holding you up than letting you in, and that’s not the same thing.
On my back, though, it makes a far stronger case for itself. The surface feels stable and supportive, and the sensation is that your lumbar area is being held rather than sagging. A lot of foam mattresses that aim for plushness can feel great for ten minutes and then subtly let your midsection dip, especially if you carry more weight around the torso. This one resists that. If you’re a back sleeper who wants a firmer, flatter posture, I can see why you’d like it immediately.
For stomach sleeping, it’s similar: the firmness works in your favour because it helps stop your hips from dropping too low, which is a common cause of lower back strain for front sleepers. I’m not here to recommend stomach sleeping as a habit because many physios would rather you didn’t, but if that’s how you sleep, you generally do better on something that keeps your pelvis elevated and your spine straighter. The Diamond Spring Free Deluxe is decisively in that camp.
Now, the cooling. The mattress is clearly designed to address overheating, with the PolarLuxe cover and the graphite-infused Diamond Cool foam. And to be fair, there is a fresher initial feel than some traditional memory foam beds. But I’m not going to oversell it, because in store my honest impression was that it still felt like a foam mattress that will retain some warmth. Foam, by nature, isn’t as ventilated as a good pocket sprung construction with airflow through the spring unit. Graphite particles and cooling yarns can help disperse heat at the surface and reduce that “hot spot” feeling, but they don’t create true breathability in the way an open internal structure does.
If you’re a mild-to-moderate warm sleeper, you may find this “cool enough”, especially if you pair it with breathable bedding and a decent protector. If you’re the type who genuinely runs hot at night and wakes up sweaty, I’d keep your expectations grounded. I’d also say that firm foams can sometimes feel warmer because you have more consistent body contact with the surface, rather than sinking into a pocketed cradle with airflow around you. That’s not a deal-breaker, but it’s a reality worth stating clearly.
Suitability
This mattress has a very specific audience, and if you fall into it, you’ll probably rate it highly. If you don’t, it could be an expensive mistake, even with a trial.
The firm tension will best suit back sleepers, and I’d go as far as to say that is its home territory. If you’re someone who likes a mattress that feels stable, level, and supportive without a lot of bounce, the Diamond Spring Free Deluxe makes a convincing first impression. It encourages a straighter posture and doesn’t let your pelvis sink away, which can be a real problem on softer all-foam designs. In-store, back sleeping felt “sorted”, like the mattress was doing the job without fuss.
Some stomach sleepers will also get on with it well, particularly those who feel uncomfortable on softer beds and who regularly wake with lower back tightness. Again, the firmness is the feature. The mattress keeps you closer to the surface and discourages the hammock effect. If you’re a combination sleeper who spends part of the night on your front and part on your back, this could be a practical compromise.
Side sleepers, though, are where I draw a very firm line. If you mostly sleep on your side, I would not recommend this mattress based on how it presented in store. The tension is simply too uncompromising for the shoulder and hip to sink in the way side sleepers typically need. This is even more relevant if you have an hourglass figure or a pronounced hip-to-waist ratio. Those bodies need more contouring, otherwise you end up either with pressure points or with your spine pushed out of neutral alignment. People sometimes buy firm mattresses thinking “firm equals healthy for my back”, but that’s not universally true. For side sleepers, too firm can be exactly what causes discomfort, tingling, and restless sleep.
If you’re a couple with different sleep styles, you need to be honest about who is going to compromise. If one of you is a dedicated back sleeper and the other is a dedicated side sleeper, this mattress will likely please one and frustrate the other. The good news is that foam can offer strong motion isolation, and in general, spring-free designs reduce the transfer of movement across the surface. In store, the mattress felt fairly “dead” in a good way, meaning it didn’t react wildly when shifting position. That can be brilliant for light sleepers who wake when their partner moves. But motion isolation isn’t much comfort if you’re waking up with a numb shoulder.
Finally, a quick practical suitability note: because this is a 29cm deep mattress, check your fitted sheets and your bed frame’s side rails. Deep mattresses can sit proud on some frames, and you don’t want a shallow fitted sheet pinging off at 2am. Also ensure your base is supportive enough, particularly if you’re using slats; the 7.5cm slat-gap rule is not optional if you want the mattress to perform as intended over time.
What customers thought
The customer feedback provided is short but very telling in tone, and it aligns with my showroom impression in a few key ways. One reviewer describes it as a “wonderful mattress” and says they feel “very well supported” with the “most comfortable night’s sleep”. Another calls it a “reasonable price mattress” and “super comfortable” and says it’s a “great purchase”. Those are exactly the kinds of reactions I’d expect from the right sleeper type on this model: people who value support and like a firmer feel tend to be the most enthusiastic about beds like this, because they experience that immediate sense of stability that softer mattresses don’t give them.
It’s also worth pointing out what isn’t being said. There’s nothing here about it being cloud-soft, nothing about deep pressure relief, nothing about it transforming side sleeping. The praise is about support and comfort in a broad sense, which often suggests the mattress is doing the fundamentals well. In a retail environment, “I feel supported” is one of the most reliable positive signals you can get, because it means the spine and pelvis feel controlled, and the sleeper feels held rather than swallowed.
That said, I always apply a bit of realism to customer reviews, especially short ones. Many people leave feedback after the first few nights, when a new mattress feels exciting and different. Foam also tends to have a honeymoon period where everything feels crisp and responsive before it settles slightly. That’s not a criticism of this mattress specifically; it’s just how materials behave. The fact Emma backs this with a 200-night trial is important, because it gives you enough time to work out whether the firmness is genuinely right for your body or whether it’s only “right” for ten minutes in a showroom and two nights at home.
Also, comfort is deeply personal. A firm mattress can feel like bliss to one back sleeper and like misery to a side sleeper. So while the customer comments reinforce that it’s supportive and comfortable, they don’t override the physical reality of how this tension tends to behave across different sleep positions.
The verdict
After testing the Diamond Spring Free Deluxe Mattress in store, my opinion is clear: this is a well-built, premium-feeling foam mattress that knows exactly what it wants to be, and it will absolutely delight the right buyer while disappointing the wrong one. The design is polished, the cover feels genuinely nice against the skin, and the overall construction gives the impression of something engineered rather than thrown together. If you like a firm, stable mattress that keeps you level and supported, it’s hard not to appreciate what Emma is doing here.
My main scepticism sits squarely with the cooling narrative. Yes, the PolarLuxe cover gives you that initial refreshing sensation and the graphite foam is a credible attempt at thermal management. But no, I don’t think this suddenly behaves like a highly breathable, airy mattress. It’s still an all-foam build, and in store it still read as slightly warm in the way foam often does. If cooling is your number one priority, I’d consider whether you’d be better served by a well-ventilated pocket sprung hybrid, or at the very least plan to pair this with breathable bedding and a proper protector that doesn’t trap heat.
Where I won’t sit on the fence is suitability. The firmness is the defining trait, and it’s not negotiable. I would recommend it for back sleepers without much hesitation, and for some stomach sleepers who need strong pelvic support. I would not recommend it for most side sleepers, particularly anyone with sharper curves through the hips and shoulders, because the tension is likely to feel unyielding and may create pressure points over a full night. In a quick showroom test you might convince yourself you can “make it work”, but comfort at minute five and comfort at hour five are very different things.
Overall, if you’re shopping for a firm, spring-free mattress with a modern feel, a washable cover, a reputable brand behind it, and the reassurance of a long guarantee and a meaningful trial, the Diamond Spring Free Deluxe deserves to be on your shortlist. Just be honest about how you sleep, be realistic about the cooling claims, and make sure your bed base is appropriate. Get those details right and it can be a genuinely strong purchase; get them wrong and you’ll spend your nights fighting a mattress that’s simply built for someone else.
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