SweetNight Coolnest Ultra Review

In This Review
Performance Tests | Firmness | Support & Sleeping Positions | Design | Materials | Comparisons | FAQs

At NapLab, we put each mattress to the test.

We test 10 different factors that impact the performance, comfort, and feel of the mattress. We then take the results of those tests and compare them to every mattress we’ve tested to date.

Check out the full performance table below to see how this mattress ranks:

Factor	SweetNight Coolnest Ultra	Average
Overall Score	8.50	8.52
Price (Queen)	$930	$1,143 (Memory Foam only)
Cooling – Score	8.0	8.6
Sinkage – Depth	2.39″	2.25″
Sinkage – Feel	Deep	Moderate
Motion Transfer – Score	8.8	8.2
Motion Transfer – Acceleration	7.74 m/s²	8.80 m/s²
Response Time – Score	9.7	8.7
Response Time – Mostly Recovered	0.2 sec.	0.4 sec.
Response Time – Fully Recovered	0.6 sec.	1.0 sec.
Bounce – Height	5.66″	8.65″
Bounce – Feel	Very Low	Moderate
Edge Support – Score	8.1	8.7
Edge Support – Sitting	4.50″	3.84″
Edge Support – Lying	Good	Good
Sex – Score	6.9	8.2
Pressure Relief – Score	9.0	8.6
Comfort Layer Thickness	6.25″	4.38″
Mattress Thickness	15.50″	12.35″
Off-Gassing – Score	8.1	7.9
Off-Gassing – Smell	Strong	Strong
Off-Gassing – Days	7 days	8 days
Company – Score	9.0	8.8
Trial	100 nights	195 nights
Warranty	10 years	41% have lifetime warranties, average of other 59% of mattresses is 13 years

How is SweetNight Coolnest Ultra Different?

The SweetNight Coolnest Ultra is a 15.50″ memory foam mattress with an overall performance level that is below average, but it is also paired with a budget price. If you’re willing to work with a few disadvantages to achieve a low sticker price, the Coolnest Ultra could be a good mattress to consider.

Advantages

Aside from the lower price, other advantages of the Coolnest Ultra include better motion isolation than average, faster material response time, and great pressure relief.

Neutral Factors

This mattress has deep sinkage and very low levels of bounce. Both bounce and sinkage are preferential factors, and different sleepers will likely have different preferences in these areas.

Disadvantages

Disadvantages of the Coolnest Ultra include a worse cooling score, weaker edge support, and a pretty disappointing sex score. For couples, the Coolnest has a few notable strikes that may make this mattress less appealing.

The SweetNight Coolnest Ultra has good cooling. During our tests, I felt a slight level of heat retention around my body. Fortunately, it was nothing extreme and I wouldn’t describe it as “hot”.

This mattress is equipped with a cool-to-the-touch cover. While that cover is cool when you first lie in the bed, it quickly loses the cooler feel after lying in the same spot for a couple of minutes.

In addition, the mattress is equipped with phase change materials infused into the top foam layer. And finally, a combination of a perforated 3rd foam layer and air / zoned support channels cut into the 4th foam layer help to improve breathability and airflow.

• Baseline Temperature – the temperature of the mattress before anyone lies on it
• Maximum Temperature (0 minute) – the temperature of the mattress after lying on it for 15 minutes
• Ending Temperature (5 minute) – the temperature of the mattress after being lied upon and having no one on it for 5 minutes

While this combination of design and material factors is helping to improve cooling, they are not miracle workers. Fundamentally, this is still an all-foam memory foam mattress.

All foam mattresses, but especially all foam memory foam mattresses, typically struggle more with heat retention and that’s what we experienced here as well.

In our objective temperature tests, we measured a max surface level temperature of 91.6° F. This is 1.3° warmer than the average of 90.3° F, based on all of our tests to date.

After getting off the mattress, the temperature declined by 5.8 degrees from minutes 0 to 1, which is 1.0 degrees cooler than the average 0 to 1 minute decline of 4.8 degrees.

When we consider the combination of objective data, my subjective experiences, and an analysis of the materials, I’m confident in my view that cooling is good.

The SweetNight Coolnest Ultra has deep sinkage. During our tests, we measured a pressure point sinkage depth of 2.39″. This is 0.14″ more sinkage than the average sinkage depth of 2.25″, based on all of our tests to date.

The level of sinkage is documented in the image below.

The mattress creates a dramatic body contouring hug. The Coolnest Ultra has a classic memory foam feel. It allows the body to sink down into the foam layers and create an exacting and significant hug around the precise shape of your body.

That hugging sensation creates great comfort and pressure relief. However, for some sleepers it can feel more restrictive. To be comfortable on this mattress, you’ll want to be sure you prefer a more notable hugging sensation around your body.

The SweetNight Coolnest Ultra has a low level of motion transfer. During our tests, we measured a total acceleration range of 7.74 m/s². This is 12% less motion transfer than the average of 8.80 m/s².

All-foam memory foam mattresses typically create lower motion and that’s exactly what we measured here as well. The all-foam design with thick memory foam comfort layers greatly absorbs and disperses energy, which results in less bounce on the mattress.

This combination of factors is able to then create substantially less energy and motion transfer on the mattress.

The level of motion transfer is also documented in the video below.

In our motion transfer chart, which visualizes our accelerometer data, we can see the highest motion peaks from 0 to 0.25 seconds. Motion declines significantly immediately thereafter.

By 0.70 seconds, we’ve returned to near-zero levels of energy, which is 0.21 seconds shorter than the average motion duration of 0.91 seconds.

Both motion intensity and motion duration are notably lower than average. As a result, the total motion transfer experience on the mattress is low and I expect most sleepers will find this level of motion to be more than satisfactory.

The SweetNight Coolnest Ultra has an extremely fast mostly recovered response time and a very fast fully recovered response time.

In our mostly recovered test, we measured a recovery speed of 0.2 seconds, which is 0.22 seconds faster than the average of 0.42 seconds, based on all of our tests to date.

In our fully recovered responsiveness test, we measured a recovery speed of 0.6 seconds, which is 0.43 seconds faster than the average of 1.03 seconds. Typically, memory foam mattresses will have a slower material recovery speed, but that’s not what we measured here.

The level of responsiveness is documented in the video below.

SweetNight is using a faster responsive memory foam. The memory foam is able to create the notable body-contouring hug that memory foam fans love, while at the same time remaining responsive enough to facilitate good ease of movement and avoid any type of a “stuck” feeling in the mattress.

Overall, I’m pleased with these material recovery speeds and expect most sleepers will find them satisfactory.

The SweetNight Coolnest Ultra has a very low level of bounce. During our tests, we measured a total bounce height of 5.66″. This is 2.98″ less bounce than the average of 8.64″, based on all of our tests to date.

The lower level of bounce is a product of the all-foam design and the thick memory foam comfort layers. Memory foam, by its nature, greatly absorbs and disperses energy. This attribute also means that memory foam ends up being less resilient.

The level of bounce is also documented in the video below.

The lower resiliency and greater energy absorption result in a less bounce. A lower level of bounce is beneficial for motion transfer. However, less bounce does negatively impact sex performance.

The SweetNight Coolnest Ultra has good sitting edge support and good lying edge support.

In our sitting edge support test, we measured a sitting sinkage compression of 4.50″. This is 0.64″ more sitting sinkage than the average of 3.86″, based on all of our tests to date.

The level of edge support while seated is documented in the images below.

While lying directly on the edge of the mattress, I felt that the support was good in all sleeping positions. This mattress does not utilize any type of reinforced foam or materials along the perimeter edge.

That said, and to be fair, perimeter edge reinforcing materials in an all-foam mattress is fairly rare and rarer yet at this price point.

The level of edge support while lying is documented in the images below.

Nevertheless, it is clear that edge support for both sitting and lying leave much to be desired. The combination of deeper sinkage and greater body hug creates a weakening of support along the edge, such that we see both lying support and sitting sinkage measurements earning worse scores than average.

The SweetNight Coolnest Ultra has mediocre sex performance. On the positive side, noise is minimal and pressure relief is excellent, meaning we have a quiet and comfortable mattress.

The good, but far from great, scores are cooling and edge support. Edge support measured in at 4.50” of sitting sinkage compression. This is notably deeper sinkage than average. A weaker edge support means there is less usable surface area for amorous activity.

Lastly, we need to talk about the one real con on this mattress and that’s bounce. Our bounce test measured in at 5.66”. This is significantly less bounce than average.

Sex Factor	Factor Weight	Score	Rating
Bounce	65%	6.0	Low
Edge Support	20%	8.1	Good
Noise	5%	10	Minimal
Pressure Relief	5%	9.0	Excellent
Cooling	5%	8.0	Good

When it comes to sex, more bounce is better. This bounce level makes sex more strenuous, more tiring, and less fun. To be fair, lower bounce and a worse sex performance is typical for memory foam mattresses.

So this is less of a problem with Sweetnight Coolnest Ultra specifically and rather a problem with most memory foam mattresses. If you want a memory foam mattress, you should be prepared for sex performance to be worse.

The SweetNight Coolnest Ultra has an excellent level of pressure relief. During our tests, I felt no significant pressure points on my body.

The mattress is equipped with 6.25″ of comfort material, which is 1.87″ more comfort material than the average comfort layer thickness of 4.38″, based on all of our tests to date. This mattress is equipped with a thin, non-quilted cover.

That thinner cover allows for the body to sink down deeper into the mattress and creates a more exact, precise, and dramatic hug around your body. Fortunately, the materials are also fairly responsive, so you shouldn’t feel overly restricted or otherwise “stuck” in the foam layers.

All that being said, this mattress has a noted memory foam hugging sensation around the body. You’ll want to make sure that you prefer a strong level of body hug in order to find the Coolnest Ultra comfortable.

In our objective pressure mapping tests we measured a max PSI of 0.43, which is well within the 1.0 PSI threshold that we ideally want to see.

Pressure Relief (PSI)	Average	Maximum
Side Sleepers	0.10	0.33

Pressure Relief (PSI)	Average	Maximum
Back Sleepers	0.07	0.41

Pressure Relief (PSI)	Average	Maximum
Stomach Sleepers	0.07	0.43

When I consider our objective pressure mapping tests, material thickness, material quality, and my subjective experience on the mattress, I’m confident most sleepers will find the pressure relief to be excellent.

The SweetNight Coolnest Ultra had a strong smell upon the initial unboxing. The mattress smelled for 7 days. This is 0.6 days shorter than the average smell duration of 7.6 days.

SweetNight mattresses come with a 100-night trial period and a 10-year warranty. Shipping and returns are both free.

Company Factor	Factor Weight	Score	Data
Returns	40%	10	$0
Trial Period	30%	8.0	100 nights
Warranty	20%	8.0	10 years
Shipping	10%	10	$0
Country of Origin	0%		Indonesia

Comparing 121+ brands tested to date, the average trial period is 195 nights, 85 nights more than SweetNight offers.

The average warranty is 13 years, which is 3 years more than the SweetNight warranty. Additionally, this excludes the 43% of mattresses that offer lifetime warranties.

The Sweetnight Coolnest Ultra Mattress is only available in a single firmness option, which they call “Medium / Medium Plush.” However, it is also available in three different height options – 12”, 14”, and 16”, with more foam material being used in those thicker versions.

For this reason, despite the singular firmness option, feel and firmness are likely to vary across these versions.

Based on my experience testing the 16″ version, I would rate it at a medium feel, with a rating of 5 out of 10, where 10 is the most firm.

Support on the SweetNight Coolnest Ultra is excellent. During our tests, I felt well supported in all sleeping positions.

Support Factor	Data
Comfort Layer	6.25″
Support Layer	9.25″
Firmness	Medium
Body Contour	Dramatic
Zoned Support	Yes
Reinforced Edge	No

The mattress is equipped with a 9.25″ support layer. This is 1.27″ thicker than the average support layer thickness of 7.98″, based on all of our tests to date. Mattresses that create the best support do so by creating a neutral alignment for the spine and creating ample pressure relief.

The Coolnest Ultra achieved both of these requirements without any issues. This mattress is available in a single firmness, which we rated at a medium feel, 5 out of 10 on our firmness scale. A medium feel works well for all sleeping positions and most sleepers.

Check out the table below to see the sleeper weights and sleeping positions that would be best suited for this mattress.

Sleeper Weight	Stomach Sleeper	Side Sleeper	Back Sleeper
Under 150 lbs.	Yes	Yes	Yes
150-250 lbs.	Yes	Yes	Yes
250-300 lbs.	Yes	Yes	Yes

In all mattress tests, we make it a point to cut the mattress open and assess the material quality. We measured memory foam density between a 1.71 and 2.92 PCF. The 1.71 PCF memory foam is quite low and could be a durability issue.

While I’m pleased by the 2.92 PCF for the secondary memory foam layer, that layer is only 0.25” thick, which is not thick enough to make a major impact on comfort or durability. Poly foam density was better, with the topmost poly foam measuring in at a 3.05 PCF. That’s well within the “outstanding” poly foam density tier.

The other poly foam comfort layer measured in at a 1.47 PCF, which is fairly low. Denser foams typically perform better, last longer, and sag less. Overall, I think it’s fair to say that these density levels are about what we expect at this price point, and yet, I do still wish they were denser foams.

Having a 1.71 PCF memory foam that’s 2.75” thick is quite concerning. That is a very low density for a memory foam and I’m concerned that the layer may not remain durable over time. That being said, this is still a very inexpensive mattress to be 16” thick, so it is reasonable that the brand needed to make quality cutbacks in order to hit this price point.

Moving on, this mattress is equipped with zoned support via a channel-cut piece of foam. While this type of zoning is still technically zoned support, in my view, it’s the least impactful type of zoned support. Individually cut foam blocks in different zones make a more meaningful support impact.

Based on all of my tests to date, an analysis of the materials, and my subjective experiences, I’m confident most sleepers will find support on the SweetNight Coolnest Ultra is excellent.

The SweetNight Coolnest Ultra is a 15.50″ memory foam mattress that comes in a single firmness option—Medium. It has a thin cover and an ultra-thick profile.

Design Factor	Data
Type	Memory Foam
Thickness	15.50″
Cover Type	Thin
Weight	90 lbs.
Has Handles	No
Fiberglass-Free	Yes
Ships in a Box	Yes

Within the SweetNight collection, the Coolnest Ultra is the top-of-the-line model. It skips any extra bells or whistles. Even so, for a thick, memory foam mattress on a budget, it could be a good option.

The SweetNight Coolnest Ultra is 15.50″ thick and contains a combination of poly foam, memory foam, and support foam. From top to bottom, here is a full list of the materials used in this mattress:

Layer Type	Thickness	Manufacturer’s Specs	Tested Specs
Thin Cover	0.25″	Not Available	Not Available
Poly Foam	1.00″	Not Available	3.05 PCF
Memory Foam	0.25″	Not Available	2.92 PCF
Memory Foam	2.75″	Not Available	1.71 PCF
Poly Foam	2.00″	Not Available	1.47 PCF
Support Foam	9.25″	Not Available	1.65 PCF
Thin Cover	0.25″	Not Available	Not Available

The SweetNight Coolnest Ultra has a thin cover that is 100% polyester, giving it a soft and stretchy finish. An arched stitching pattern gives this mattress a modern look, with subtle blue accents hinting at the cool technology on this mattress.

The cover uses what SweetNight calls “Gradient Ice Silk”, which is designed to improve cooling with over 10,000 micro-pores/cm². That said, I did not find the cooling on this mattress to be particularly impressive nor offer a cool-to-the-touch feel. While the marketing language around the cover sounds impressive, I found the real world performance to be good, but not great.

The comfort layer is 6.25″ thick and made of three layers of foam. Directly below the 0.25″ thin cover is a 1.0″ poly foam (white + blue speckled foam), followed by a thin 0.25″ memory foam (teal foam), and then a 2.75″ memory foam (blue foam).

The core layer of memory foam is what gives the mattress its more distinctive, dramatic contour. But the inclusion of the poly foam above helps to improve overall mattress cooling and material response time.

Below the memory foam is a convoluted 2.0″ poly foam (gray foam). This layer serves as a transitional layer between the comfort materials and the support layer below.

The support layer is 9.25″ thick and includes a 9.0″ support foam layer (light gray foam). Directly at the base of the mattress is a similar 0.25″ thin cover, like what we saw at the top of the mattress.

The Coolnest Ultra is not a flippable mattress, but we are allocating some thickness to the base of this mattress to account for this cover.

Product Evolution

The SweetNight Coolnest Ultra is new to the SweetNight collection, hitting the collection as the top-tier evolution of memory foam mattresses from SweetNight. This mattress was released around August 2026, and there have been no notable changes made to the mattress since its release.

Other Mattresses to Consider

Not sure if the SweetNight Coolnest Ultra is the right pick for you? Check out these three other memory foam mattresses under $1,000 for alternatives you may want to consider.

Frequently Asked Questions

Still have questions? Check out some of the top FAQs on the SweetNight Coolnest Ultra mattress below and get the answers you’re looking for.