5 Best Split Tension/Dual Firmness Mattresses 2024

There are two options if you share a bed with someone who wants a much firmer or softer mattress than you (assuming you don’t want to split up or sleep in separate rooms).

One option is to buy two long single mattresses (available from Mattress Online) which are also called European single mattresses (available from Mattress Next Day) They usually measure 90cm wide and 200cm long, so if you put two side by side they’ll fit nicely on a standard super king size bed frame (180cm x 200cm).

The other option is a split tension mattress which is also known as a dual tension mattress or a dual firmness mattress in the UK.

There aren’t all that many split tension mattresses on the UK market and they tend to be quite expensive, but we’ve picked out five split tension and dual tension mattresses which are worth considering.  

Prices mentioned are for the king size version and are correct at the time of writing.  

Split tension Flaxby mattress
A split tension mattress can provide the ideal solution for couples

1. Flaxby Nature’s Finest 4450 Pillow Top Mattress – king or super king – £2199/£2499

You might not have heard of Flaxby mattresses but they’ve got an impressive pedigree. 

They are made by a UK company called Harrison Spinks, which was named as the manufacturer of the year at the main bed industry awards in 2015 and 2018. The same company also makes a lot of mattresses for John Lewis & Partners, so you know they’re at the posh end of the market.

For your money, you get a traditionally made mattress which uses pocket springs. For anyone who doesn’t speak mattress jargon, that just means that it is made using good quality springs rather than ‘open coil’ springs which are much cheaper and grottier. 

There are other things to include in the ‘pros’ column for this mattress. It is hand tufted and has hand side stitching, which are two signs of quality and should mean it won’t fall to pieces and lose its shape.

In the ‘cons’ column for this mattress is the fact that it’s single sided and so can’t be flipped over. That means that you rotate it round to help stop sagging over time (a problem we all face with age). Another downside is the warranty, which is not especially generous at five years.

​The split tension version of the Flaxby All Seasons Mattress is available as a king size split tension mattress or as a super king size split tension mattress. It is medium tension on one side and soft on the other.

It is sold by Dreams which has a 40 Night Comfort Guarantee.

Flaxby dual tension mattress for couples
This split tension mattress is made by an award winning mattress brand
Harrison Spinks mattress label
Flaxby is made by the award winning Harrison Spinks mattress company
dreams logo
Search latest price on ​Flaxby All Seasons Split Tension mattress
Tufted finish + hand side stitching + luxury UK brand
Tufted finish + hand side stitching + luxury UK brand Show Less

2. Dormeo S Plus Memory Foam Split Tension Mattress – double, king or super king – £1038/£1278

Dormeo’s split tension mattresses are certainly innovative.

Both sides of the mattress have a firmer and a softer side so you can mix and match until you find the perfect combination. 

The Dormeo S Plus memory foam mattress made from various types of foam, rather than using pocket springs which is what most of us are used to. However, there’s a lot to be said for foam mattresses and this one actually uses some special spring-shaped foam which it reckons offers the best of both.

Some people find memory foam makes them feel a bit warm, but Dormeo claim their design is much more breathable. Fans of memory foam like the way that it offers consistent support all over.

This mattress is also unusual because you can buy this dual tension mattress in double, king size and super king size. Most split firmness mattresses just come in the larger sizes. 

It comes with a 60 night ‘comfort trial’ so you can send it back if you don’t like it. There’s also a 15 year warranty which is longer than most mattress brands. Make sure you read the Terms and Conditions with both of those things though.

Dormeo S Plus split tension mattress
The Dormeo S Plus split tension mattress has a trial period…
Dormeo S Plus dual firmness mattress
…and a clever design to help you get comfy
dormeo logo
Search latest price on Dormeo S Plus mattress at Dormeo.co.uk
15 year guarantee + double sided design
15 year guarantee + double sided design Show Less

3. Silentnight Yours and Mine Split Tension Mattress – £1100 – king size or super king Size

Silentnight is probably the name that most people would come up with if you asked them to name a UK mattress brand. I think they’d also want to know why you were asking such a random question but let’s not dwell on that.

The main advantage of this split tension mattress over most others is that you can choose from three different firmness levels rather than two (soft, medium or firm).

You start by picking the top layer, which can be ‘Geltex’, ‘memory’ or ‘eco comfort’. You need to agree on this bit as it will be the same on both mattresses. Geltex and memory foam are both types of foam but from what I can tell, Geltex bounces back more whilst memory foam sinks and hugs you a bit more. ‘Eco comfort’ mattresses are made from ‘sustainable fibres’ which is an effort to be greener. The cheapest option is ‘eco’ with ‘memory foam’ as the mid-priced option and ‘Geltex’ as the most expensive option.

You then choose whether you want the bottom layer on your side of the mattress to be soft, medium or firm. The general rule is that lighter people need softer mattresses than heavier people, so this split tension mattress is a good option if you’re a sumo wrestler who is married to a jockey.

Silentnight couples mattress
The Silentnight split tension mattress has more customisation options than most
silentnight mattress
Search latest price on Silentnight Yours & Mine split tension mattress
UK's biggest mattress brand + choice of styles and designs
UK's biggest mattress brand + choice of styles and designs Show Less

4. Flaxby Nature’s Finest 8150 DNAir Split Tension Mattress – king or super king – £2099/£2499

What’s this? Another Flaxby mattress?

Yes indeed, dear reader.

This Flaxby mattress is another which lets you have one side medium tension and the other side firm, but it has a couple of upgrades from the All Seasons model featured earlier (see #1).

Most significantly, it is double sided so you can flip it over to help extend its life. Of course, you’ll need to be pretty strong to turn over a super king size mattress but perhaps you could keep a forklift truck in the corner of your bedroom.

It also has a load of posh natural materials inside including ‘layers of wool and mohair sourced from farms in and around Yorkshire’. The general idea is that these are naturally breathable.

The 8150 number refers to the number of springs. It’s tempting to get a bit obsessed with the spring count on mattresses and 8150 is certainly a huge number which will offer plenty of support. However, it’s worth realising that you can only fit about 2000 full size pocket springs onto one layer of a mattress. The numbers are usually bumped up with layers of smaller springs which add some comfort.

The main disappointment I have with this mattress is that it only comes with a five year warranty. For a price tag of around £2000 I would expect a 10 year warranty.

Flaxby 8400 dual firmness mattress
The upgraded Flaxby mattress is double sided and has more springs
Flaxby mattress logo with Harrison Spinks logo
Flaxby is an excellent quality mattress brand
dreams logo
Search latest price on Flaxby 8400 split tension mattress
Double sided design + posh UK brand + respected retailer
Double sided design + posh UK brand + respected retailer Show Less

5. Hyde & Sleep Memory Foam Split Firmness Mattress – king or super king – £999 – £1299

Hyde & Sleep have a few different split firmness mattresses including the Ruby (half firm, half very firm) and the Citrine (half medium, half firm) and the Topaz (half medium and half firm).

Unlike the others on this guide to dual tension mattresses, the Hyde & Sleep Topaz models is a ‘hybrid’. That means that it uses a combination of pocket springs and memory foam. Pocket springs offer that familiar bouncy feel that you get from a mattress whilst memory foam is good for spreading out weight evenly.

Meanwhile, the Ruby and the Citrine models are both memory foam mattresses. Personally, I like memory foam mattresses but some people find that they make them feel a little warm.

Each model comes with a ‘zoned’ design. This is a piece of mattress jargon you will often see in product descriptions. The idea is that a mattress offers differing levels of support depending on which part of your body is like to be sleeping on it. Most of your weight is around your hips (no offence) so zoned mattresses tend to be firmer around this area than they are around your shoulders and feet.

You get a five year guarantee and a 40 Night ‘Sleep Guarantee’. Neither of those are remarkable for a mattress of this price, but it’s not too bad. They Hyde & Sleep is owned by Dreams, although it was previously run separately.

Hyde and Sleep mattress
The Hyde and Sleep range of mattresses have several split tension options
Hypnos logo
Search latest price for Hyde and Sleep split tension mattresses
Sold by Dreams which has a good reputation + 5 year warranty + memory foam design
Sold by Dreams which has a good reputation + 5 year warranty + memory foam design Show Less