Emma Diamond Degree Topper review: supreme comfort for your old mattress

The Emma Diamond Degree Topper is comfortable, supportive and made from quality materials… but is it worth the price tag?

Emma Diamond Degree Topper review
(Image credit: Emma)
T3 Verdict

If you have an old saggy mattress or you want extra comfort from your bed, the Emma Diamond Degree Topper is the perfect choice to upgrade your sleep set-up. Made of layers of firm foam, this topper moulds comfortably to the body in all sleep positions but doesn’t give you that sinking feeling. While the price is high and it often runs hot, the Emma Diamond Degree Topper offers supreme and premium comfort for a great night’s sleep.

Reasons to buy
  • +

    Insanely comfortable

  • +

    Memory foam has that sinking feeling but it’s also quite firm

  • +

    Stays in place

Reasons to avoid
  • -

    Runs a bit hot

  • -

    Pricey compared to other toppers

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In T3’s Emma Diamond Degree Topper review, I put this premium mattress topper to the test to see if it delivered a comfortable and supportive night’s sleep… and it didn’t disappoint.

If your current mattress is on its last legs and you can’t afford to replace it just yet, the best mattress toppers give old saggy mattresses a new lease of life. Sitting on top of your mattress, a mattress topper provides extra support and comfort to help you sleep better and they’re a cheaper investment than a full mattress (although if you’re looking for a new one, check out our top picks for the best mattress).

As one of the most popular mattress companies in the UK, Emma has a wide range of mattresses and sleep products, including its Emma Diamond Degree Topper. Made from two different layers of foam, the Emma Diamond Degree Topper (which is also called the Premium Topper) is a “luxury winner for temperature regulation” and credits itself as providing faster deeper sleep and maximum comfort.

So, does the Emma Diamond Degree Topper live up to the hype? And most importantly, is it worth the hefty price tag? Keep reading for my full Emma Diamond Degree Topper review.

Emma Diamond Degree Topper review: Unboxing

The Emma Diamond Degree Topper arrived in a big cardboard box which was surprisingly light to manoeuver into my bedroom. The topper came rolled up and wrapped tightly in plastic. There was quite a bit of plastic to get through, but once it was removed, the topper sprung free and unrolled itself.

The Emma Diamond Degree Topper was easy to unfold and it expanded nicely, so I didn’t need to wait for it to come back to its normal size like you often do with some bed-in-a-box mattresses. As you can see in the video below, I easily put it on top of my mattress and it fit my double mattress perfectly. My double sheet also fit well over both the mattress and topper.

One thing I did notice was that the Emma Diamond Degree Topper has a strong chemical smell. This is to be expected with mattresses and toppers that arrive this way and while the smell did dissipate, it was pretty strong for my first few uses. It’s also worth noting that some toppers will come with elasticated straps or skirts to fit over the mattress but the Emma Diamond Degree Topper doesn’t have this, so it’ll just lie on top of your mattress.

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Emma Diamond Degree Topper review: Design & features

The Emma Diamond Degree Topper is made of two different foam layers, the Diamond Degree foam and the Adaptable HRX comfort foam. As Emma has recently updated its Emma Diamond Degree Topper to its Emma Premium Topper, the material is slightly different, so instead of the Diamond Degree foam, you’ll get the Premium ThermoSync foam.

Other materials that make up the Emma Diamond Degree Topper are polyester, lyocell, elastane and polypropylene. It also has a removable elastic cover over the entire topper. I thought the design was really cool, as it has patterns on the cover and the words ‘Diamond Degree’ written into the fabric which was a nice touch. The cover and topper is incredibly smooth and springy to the touch, and with sheets on, you won’t feel the markings on the fabric come through while you sleep.

The main features of the Emma Diamond Degree Topper is its Diamond Degree technology (or Premium ThermoSync technology) and graphite particles. This technology and the open-pored foams work together to regulate temperature and dissipate excess body heat with the use of graphite’s high thermal conductivity. The Emma Diamond Degree Topper also states that it offers premium comfort and optimal pressure relief for all sleeping positions – so let’s see if it does what it says on the tin!

Emma Diamond Degree Topper review

(Image credit: Future)

Emma Diamond Degree Topper review: Performance

My first impression of the Emma Diamond Degree Topper – aside from the strong smell – was wow, this topper is comfortable! The topper is quite firm but it moulds nicely to the body, cradling and releasing pressure without enveloping you. I tried out the double size which measures 135 x 190 x 09 cm and weighs approximately 12 kg and I was impressed by the thickness of it. It doesn’t have that sinking feeling that foam mattresses tend to have, but it still felt soft to lie on.

The first night I slept on it, I noticed that the motion isolation was pretty minimal. I tend to toss and turn a bit throughout the night – probably because my fiancé takes up a lot of room! – but I didn’t feel the topper move at all, nor did I wake him up by moving. Speaking of moving, the Emma Diamond Degree Topper doesn’t have anything that fixes itself to your mattress, meaning it could slip and slide all over the place. However, it doesn’t move around very much and if it does, it’s not noticeable. When I changed my sheets, I saw it had inched to the right a bit but it was easy to correct, so it definitely wasn’t an issue for me.

One negative I did find with the Emma Diamond Degree Topper was its temperature regulation. The brand states that its technology is designed to dissipate excess heat but I found that it ran a bit hot. I’m a bit of a sweaty sleeper anyway, but I did wake up a few times in the night feeling hot and sweaty. For me, the temperature regulation could be better but it’s definitely not awful, and if you’re not a sweaty sleeper, you’ll probably get on with it just fine.

Emma Diamond Degree Topper review: Pricing

Compared to other mattress toppers, the Emma Diamond Degree Topper is one of the more expensive ones on the market. The Single is £330, the Small Double is £400, the Double is £500, the King is £540 and the Super King is £580. Emma offers free delivery and returns, a 100-night trial and a 10-year guarantee.

While this is pretty pricey for a topper, it’s nowhere near as expensive as a new mattress so it’s definitely worth considering. It’s also worth noting that Emma runs regular sales throughout the year, so you’re unlikely to spend full price on its products. To keep up-to-date with these sales, check out the best Emma mattress deals for more.

Emma Diamond Degree Topper review

(Image credit: Emma)

Emma Diamond Degree Topper review: Verdict

I loved using the Emma Diamond Degree Topper and found it to be insanely comfortable. The topper delivers a supportive night’s sleep for all positions, minimal motion isolation, pressure relief and the design looks and feels nice to the touch. Despite the lack of elastic to keep it fixed to your mattress, the Emma Diamond Degree Topper barely moves while you sleep on it, too.

I think the temperature regulation could be better as I slept quite hot while using it and it’s expensive compared to similar products from other brands. But in general, I’ve slept very well every night since having it and so has my fiancé. If you want a more comfortable sleep or you can’t afford to replace your old mattress right now, it’s definitely worth the investment.

Emma Diamond Degree Topper review: Alternatives to consider

A great alternative to the Emma Diamond Degree Topper is the Simba Hybrid Topper. Another popular UK mattress company, Simba uses high quality technology and materials to make its mattress products, and the Simba Hybrid Topper currently holds a top spot in our best mattress topper guide. Compared to the Emma Diamond Degree Topper, the Simba Hybrid Topper is cheaper but it’s also soft, comfortable and stays in place.

If you like the sound of the firmness of the Emma Diamond Degree Topper, another good alternative is the Soak&Sleep Soft As Down Silk Mattress Topper. These toppers have a similar thickness but the Soak&Sleep option is significantly cheaper. 

Bethan Girdler-Maslen
Home Editor

Beth is Home Editor for T3, looking after style, living and wellness. From the comfiest mattresses to what strange things you can cook in an air fryer, Beth covers sleep, yoga, smart home, coffee machines, grooming tools, fragrances, gardening and much more. If it's something that goes in your house, chances are Beth knows about it and has the latest reviews and recommendations! She's also in the know about the latest deals and discount codes from top brands and retailers.

Having always been passionate about writing, she’s written for websites, newspapers and magazines on a variety of topics, from jewellery and culture, to food and telecoms. You can find her work across numerous sites, including Wedding Ideas Magazine, Health & Wellbeing, The Bristol Post, Fashion & Style Directory, TechRadar, CreativeBloq and more. In her spare time, Beth enjoys running, reading, baking and attempting craft projects that will probably end in disaster!