Cocoon by Sealy Chill vs Siena Signature: Which cheap memory foam mattress should you buy?

Tom's Guide

24-07-2025

Cheap all-foam mattresses can have an unfair reputation as heat-trapping, quicksand-feeling, bad-smelling beds. The Cocoon by Sealy Chill and Siena 10" Signature buck that bad rap, which is why they're two of our top-rated memory foam mattresses. So which should you buy?
The Cocoon by Sealy Chill and the Siena Signature are both affordable memory foam mattresses that impressed our testers with their all-round comfort and support. If value for money is your top priority, these are among two of the best mattresses you can buy this year.
But that doesn't help you choose between them. In this guide we'll be comparing the feel, support, performance and price of the Cocoon by Sealy Chill vs Siena 10" Signature mattress, to see which is the best cheap memory foam bed for you.
Cocoon by Sealy Chill vs Siena Signature mattress: Price & trial
The Sealy Chill is a budget-friendly cooling bed at $699 for a queen
The Siena is a cheap mattress, with a queen only $359
Both offer a 10-year warranty but the Siena has a longer sleep trial
The all-foam Cocoon is a lower mid-range mattress and a queen typically sells for $699. That's a highly competitive price, sitting alongside the Nectar Classic Memory Foam mattress ($649 for a queen) and the DreamCloud Classic Hybrid Mattress ($699 for a queen.)
This price is even more appealing when you consider the Cocoon by Sealy Chill is a cooling mattress. These specialty beds are often premium options — the Cocoon is a rare budget choice (and we'll dive into how effective it is below.)
Often sold at just $359 for a queen, we think the Siena is the best cheap mattress you can buy. For a real bargain, keep an eye on the Amazon Siena store, where we've spotted a queen for as little as $278.
You'll never have to pay full price at either brand. We track mattress sales throughout the year and it's rare for the price to change at Siena. At Sealy Chill, it's practically unheard of. And Sealy throws in a free cooling bedding bundle with purchase, to sweeten the deal.
Both brands offer a standard 10-year warranty. Sealy Chill's 100-night trial is fine, and the industry average, but Siena goes a step further with a 180-night trial.
Cocoon by Sealy Chill Memory Foam Mattress: twin was $619 now $399 at Cocoon by Sealy
You can always rely on the Cocoon by Sealy Chill 35% off mattress sale but while the price is predictable, we still think this is an excellent deal. A queen is only $699 and you get a free cooling bedding bundle included, to add to your chill comfort.
Siena 10" Signature Mattress: twin $179 at Siena
Like the Cocoon by Sealy Chill, we rarely see major deal changes at Siena. And like the Sealy Chill, the Siena is so well priced we don't really mind the predictability. However, if you do want to save even more on the Siena Mattress, we recommend browsing the Amazon Siena store, where we've seen some major price drops in recent weeks.
Cocoon by Sealy Chill vs Siena Signature mattress: Materials & design
Both the Siena and the Sealy Chill are 10" memory foam mattresses
Both have a double-layer design
The Sealy Chill has an upgraded cooling cover
As affordable all-foam mattresses, the Cocoon by Sealy Chill and the Siena Signature mattresses share many similarities when it comes to design.
First, they're both 10 inches tall (although the Siena is available in other depths.) This is an average mattress height and supportive enough for most adults, but 10-inch mattresses sometimes lack pressure relief for side sleepers.
The interior of the Siena 10" Signature mattress
(Image credit: Siena)
Second, they both use two layers of foam to balance comfort and support. The upper (thinner) layer is a conforming memory foam that's intended to enhance pressure relief. The lower (thicker) foam layer is a stability foam, adding support to the design.
While both brands use their own foam formulations to create different feels — and different durability, as we predict the pricier Cocoon by Sealy Chill to last longer — the most obvious design difference is the mattress covers.
The (similar) interior of the Cocoon by Sealy Chill
(Image credit: Cocoon by Sealy Chill)
The Siena uses a breathable cover to improve air flow but the Cocoon by Sealy Chill goes a step further, infusing its cover with phase change material for a cool-to-the-touch feel and better temperature regulation.
Cocoon by Sealy Chill vs Siena Signature mattress: Comfort & support
Cocoon Chill is a medium-firm mattress, good for most sleep styles
Siena Mattress is firm, best for back and stomach sleepers
Neither mattress feels like a 'classic' memory foam
Both Siena and Sealy Chill describe their respective mattresses as a six on the mattress firmness scale (with one indicating soft and 10 hard.) However, in our experience the Cocoon by Sealy Chill is closest to this medium feel, with our testing team agreeing it was a 6.5 out of 10 which is on the lower side of medium-firm. In our Cocoon by Sealy Chill mattress review, we found it most comfortable for back and side sleepers, with good pressure relief at the shoulders and hips.
While the Cocoon by Sealy Chill has some contouring, it doesn't have much 'sink'
(Image credit: Future Ltd)
The Siena, on the other hand, delivered a different experience. Our Siena Memory Foam Mattress review team found this bed closer to a nine on the firmness scale, indicating a firm feel. With impressive support, the Siena suited our back and stomach sleeping testers but was too firm for side sleepers.
Neither mattress delivers that 'hug' feel we expect from a classic memory foam but the Cocoon comes slightly closer, contouring to the shoulders. However, these are both mattresses you lie on top of, rather than sink into.
The Siena was a touch too firm for side sleeping
(Image credit: Future)
There's one way in which these beds do perform like a traditional memory foam, though: motion isolation. All-foam mattresses are known for their ability to absorb movement and both the Siena and the Sealy Chill scored highly in this area. Even if you share with a restless partner, you should be able to sleep without disruption.
When is comes to edge support, the Siena has the clear edge (pun intended.) Thanks to that firm feel it has a higher level of support overall and if you need to press against the sides to get out of bed in the morning, you'll find the Siena provides the more supportive base.
Cocoon by Sealy Chill vs Siena Signature mattress: Temperature regulation
Cocoon by Sealy Chill is a dedicated cooling mattress
The Siena impressed us with its breathable feel
Hybrid options available of both, for better air circulation
We think the Cocoon by Sealy Chill is the best cooling mattress you can buy if you're on a budget. The phase change material used in the cover, combined with the gel memory foam, helps keep temperatures down even on hot nights.
Cheap memory foam mattresses do have a reputation for sleeping warm but the Siena surprised us with its breathable feel. This is in part due to the firm foams — as they don't hug the body, they're less likely to trap heat.
(Image credit: Future)
For a cooler experience, consider upgrading to the hybrid variety of either model. The best hybrid mattresses tend to have superior cooling, as the springs allow for better air flow.
Cocoon by Sealy Chill vs Siena Signature mattress: Which should you buy?
Buy the Cocoon by Sealy Chill Memory Foam mattress if...
✅ You tend to sleep hot: Using PCM to absorb and dissipate warmth, the Cocoon by Sealy Chill is a good choice for hot sleepers on a budget.
✅ You like to sleep on your side: While the Cocoon by Sealy Chill doesn't have the plush cushioning you'll find in our favorite mattresses for side sleepers, the memory foam delivers good pressure relief to the shoulders and hips.
✅ You need a full bed upgrade: Sealy Chill offers a free cooling bedding bundle – including sheets, pillows and a mattress protector – with every mattress purchase.
Buy the Siena 10" Signature Mattress if...
✅ You're a stomach sleeper: The Siena's firm feel offers plenty of support at the hips and spine, a common feature in the best mattresses for stomach sleepers.
✅ You're on a very tight budget: With a high quality build, we recommend the Siena for anyone who needs a new mattress but doesn't have much to spend. However, it does lack the specialist design of the Cocoon.
✅ You need to push against the mattress to get out of bed: Edge support is often the weak point in a budget all-foam bed but the Siena remains sturdy up to the sides.