Sealy Posturepedic Elevate Ultra Franklin Firm Mattress review 2024

Traditional feel and modern materials – is the Sealy Franklin Firm the ultimate choice for back pain sufferers?

Sealy Franklin Firm Mattress
(Image: © Future / Jo Plumridge)

TechRadar Verdict

The Franklin Firm is part of the Elevate Ultra range, Sealy’s premium range of hybrid mattresses in soft, medium and firm finishes. It’s a great choice for those looking for a traditional feel and a mattress that supports the spine and helps ease back pain. The firm support is best suited to back and stomach sleepers. Higher levels of motion transfer is mean it's not a great choice for restless sleepers, though.


  • +

    Excellent pressure relief

  • +

    Firm feel good for back pain

  • +

    Good temperature regulation


  • -

    Too firm for side sleepers

  • -

    Cover isn’t washable

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Sealy Franklin Firm Mattress: Review in brief

If you’re a fan of pocket-sprung mattresses, but want more modern technologies and materials, you’ve come to the right place. The Sealy Franklin Firm feels in many ways like a traditional sprung model, but uses gel-infused foam, Posturepedic coils and comfort foams for a thoroughly modern finish. 

Like many of the best mattresses on the market, the Franklin Firm is a hybrid mattress, meaning it’s made up of a combination of foams and coils. Hybrid mattresses are known for being a great choice for pressure relief and I found the Sealy to be no exception for those who sleep on their backs or fronts. As the name suggests, the Franklin Firm is a firm mattress and it does an excellent job of keeping the spine neutrally aligned in these sleep positions. It’s also supportive enough for all body weights. However, I did feel that the mattress was too firm for most side sleepers, who are likely to feel some pressure build-up at the shoulders and hips. Heavier weight side sleepers may, however, sink far enough into the mattress for pressure relief.

Sealy Franklin Firm Mattress specs

Type: Hybrid mattress
Materials: Foams, coils
Firmness: Firm 7.5-8/10
Depth: 31cm
Sizes: Single, Double, King, Super King
Weight: 23kg – 46kg 
Warranty: 7 years
RRP: £879 - £1,090 (Single), £1,079 - £1,349 (Double), £1,159 - £1,449 (King), £1,699 - £2,099 (Super King) depending on retailer

One of our main testers is prone to back ache and they praised the mattress highly for helping to get rid of aches and pains. As a lighter weight back sleeper, they did feel that it took a few weeks for the mattress to ‘bed in’, whereas our average and heavier weight testers who sleep on their backs and fronts found it comfortable and supportive from the off.

Temperature regulation on the Sealy is good, with even our hottest sleeper staying cool throughout the night. But the more traditional design means that motion transfer is quite high, so this might not be the best choice for those sharing their bed with a restless partner. 

I slept on a UK double mattress for six weeks, testing it on all major areas of performance. We’ll expand on my findings throughout this review. 

Sealy Franklin Firm Mattress review: Design

  • 31cm deep, hybrid mattress
  • Gel-infused foam is combined with steel coils for support and comfort
  • Cover isn’t washable

The Sealy Franklin Firm is made from a combination of foams and coils, but the overall feel is more like that of a traditional innerspring mattress. The top cover is a knit fabric made of 100% polyester, with 'SmarTex' to help wick away moisture and keep sleepers cool, and 'ProShield technology' to combat allergens (this comes endorsed by Allergy UK).  

A MemorySense comfort core sits in the centre third of the mattress, alongside a gel infused comfort layer, with both designed to offer pressure relief to the areas of the body that need it most. Next up is a layer of firm foam, followed by Sealy’s patented AlignSupport coils. These provide deep support and flex a little to shape to the body on initial contact. The mattress has reinforced coils around the edge to provide better edge support and is finished with a base layer that provides structure to the whole mattress. 

It's worth noting that Sealy recommends rotating your mattress twice a month for the first year, followed by once a month after this. I'd also recommend you use a mattress protector so that any stains or spills can be washed off easily – this is particularly important as Sealy’s mattress doesn’t have a removable cover. 

The Franklin Firm is one of three mattresses in Sealy Posturepedic Elevate Ultra range, with soft and medium firmness options also available. Note that although the Posturepedic range is available in both territories, the UK wing of Sealy operates completely separately to the US one (also the parent brand behind the Cocoon by Sealy Chill). 

Sealy Franklin Firm Mattress

(Image credit: Jo Plumridge)

Sealy Franklin Firm Mattress review: Support and comfort

  • Two stage responsive spring system
  • A firm mattress, which we rate at 7.5-8/10
  • Offers excellent pressure relief for back and stomach sleepers

I tested sinkage on the Sealy Franklin Firm by placing a 20kg weight in the middle of the mattress and measuring how far it sank in. At around 8-9cm, the mattress is clearly in the firmer category and this was certainly backed up by the experience of our testers. 

Our main testers are big fans of a firm bed and found the Sealy extremely comfortable, rating it particularly highly on pressure relief. Both back sleepers in the main, they felt the mattress supported them well around the hips and lower back. The Sealy’s MemorySense comfort core is designed to offer targeted support to these areas and it does an excellent job. Our lightweight tester is particularly prone to back pain but found this had pretty much disappeared after a few weeks of sleeping on the Franklin Firm. It is worth noting that they also felt that the mattress took time to ‘bed in’ and that it’s worth persevering with to get the full benefits. 

Sealy Franklin Firm Mattress

(Image credit: Jo Plumridge)

I’d also recommend the Franklin Firm to stomach sleepers, with the firmer feel doing an excellent job of keeping the spine aligned. Heavier weight sleepers should also feel well supported, with the firmer foams at the top of the mattress preventing them from sinking onto the coils. I wouldn’t recommend this mattress for side sleepers though, as they’re likely to find it too firm, leading to a build-up of pressure around the shoulders and hips. 

The Sealy Franklin Firm has much of the feel of a traditional pocket-sprung mattress, but with a little more softness in the sleep surface, due to the top foam layer. But this is still a mattress that you’ll lie more on top of than sink into, so do bear this in mind when making your selection.

Score: 4 out of 5

Sealy Franklin Firm Mattress review: Performance

  • Motion transfer is quite high
  • Decent temperature regulation
  • Edge support is particularly good when lying on the mattress

I slept on a UK double mattress for six weeks, looking at all the major areas of performance. I rated it on pressure relief, motion isolation, edge support and temperature regulation; all of which should help you to decide if this is the right mattress for your sleeping style. After only six weeks it’s impossible to make a definitive statement on the durability of the mattress, but the quality of the materials is high and I think it’s likely this will be a mattress with a good lifespan.

Motion transfer

Motion transfer is the measure of how much movement is shared from one part of a mattress to another. What does this mean when it comes to sleeping? Well, a mattress that has high motion transfer is more likely to disturb a sleeping partner if you move about in bed. This can be a particular issue if you share your bed with a restless partner who tosses and turns a lot at night.

The Sealy Franklin Firm was a little disappointing when it came to motion isolation, with the more traditional and firmer feel meaning that some movement can be felt when a partner moves about in bed. It’s certainly not the worst I’ve experienced, but it could be a consideration if your partner is particularly prone to movement, and you're a light sleeper.

I also tested the motion transfer on the Franklin Firm with a simple drop test, using a 6kg weight and a wine glass (empty of course). I dropped the weight at various distances from the glass to see the results. The glass was fairly stable at 25 inches, wobbled at 10 inches and fell over at 4 inches. These tests mimic a person moving around in bed.  

Score: 3.5 out of 5

Temperature regulation

I tested the Sealy Franklin Firm with a winter duvet (10 tog) and a thick fleece blanket as the weather was cold overnight (around -2C at the coldest during January 2023). The ambient temperature in the bedroom varied from between 11-14C.

One of our testers is prone to sleeping hot but didn’t overheat at all on the Franklin Firm. The mattress uses various materials and features to help sleepers keep cool at night. The cover contains Sealy’s patented SmarTex, which is designed to wick away moisture and help regulate body temperature. Gel infused foam also cools the mattress and springs are well spaced to help with airflow. The added edge support is also designed to provide air channels, making the mattress more breathable and even the base is designed to promote airflow. This mattress should do a good job of keeping the vast majority of sleepers cool and comfortable throughout the night. 

Score: 4.5 out of 5

Edge support

Edge support on a mattress is important as it allows sleepers to use the full width of the bed, as well as providing a stable surface for people to sit on while getting dressed. I tested the edge support of the mattress with our heaviest weight of 20kg and found that it sunk in around 8-9cm – the same as in the middle of the bed.

Sealy Franklin Firm Mattress

(Image credit: Jo Plumridge)

This confirmed my results from sleeping on the bed – the Franklin Firm has good edge support, allowing sleepers to sleep right up to the edges of the mattress. This is down to Sealy’s extra edge support, which they call UniCased XT edge support. This patented technology runs along the edge of the springs, with keys that lock into place and prevent lateral movement. I found the edges of the mattress particularly supportive for sleeping and lying on, although I did notice a little sinkage when sitting on the edge of the bed. But this is a great mattress for edge support and it’s easy to get in and out of.

Score: 5 out of 5

Should you buy the Sealy Franklin Firm mattress?

Those of us who grew up sleeping on a traditional sprung mattress will feel right at home on the Franklin Firm but are likely to appreciate the modern touches. This is a mattress that’s particularly suited to back and stomach sleepers of all weights, offering excellent spinal alignment and great pressure relief – particularly around the hips and lower back.

Back pain sufferers who sleep in these positions should see a big improvement in their aches and pains, although the mattress does need a couple of weeks to ‘bed in’ and time to make said improvements. It’s also an excellent choice for those who sleep hot, with plenty of cooling features included in the mattress that stop it from feeling warm at night. 

I think side sleepers are going to find this mattress too firm, but if you like the design of the Elevate Ultra range there are also soft and medium firmness versions available. Motion transfer is also quite pronounced, so while it's easy to change position in the bed, it’s likely that you'll be disturbed if you share the bed with a restless sleeper. Edge support is good though and you'll be able to make use of the entire width of the bed.

I really liked the traditional feel of this mattress and it's one of the best mattresses I've tested for helping to ease back pain. 

Sealy Franklin Firm Mattress review: Alternatives


Nectar Premier Hybrid Mattress
Thanks to Nectar’s evergreen mattress sales, you can usually pick up a mattress from its range for around 40% off list price. This makes the Nectar a good choice for those looking for a cheaper option. It’s also a good choice for side sleepers, with a distinctive memory foam 'hug' backed up by a double layer of springs.
Read our Nectar Premier Hybrid mattress review


Tempur Hybrid Elite Mattress
The Tempur is an excellent choice for those who share their bed with a restless partner, as the cradling material does a great job of isolating motion. The Tempur material moulds to your body shape and provides good pressure relief although edge support is poor because of this. If you prefer a mattress you’ll sink into, Tempur mattresses are some of the best. 


Eve Premium Hybrid Mattress
Eve's premium mattress is comfortable to sleep on in all positions, although it is too firm for lightweight side sleepers. Motion isolation isn't great, but there’s good cushioning and support of pressure points, plus the cover is removable and washable. 

Jo Plumridge

Jo Plumridge is a freelance writer and photographer with over 20 years of experience writing for a variety of magazines, books and websites. She writes, perhaps unsurprisingly, about photography but also extensively on all things sleep and interior design related, alongside home and tech product reviews. She’s lived in the middle of a nature reserve in Botswana and written a guidebook to New Zealand, but now spends a lot of time trying to photograph the cats she and her husband foster for a local charity - without a doubt the most challenging subjects on earth!