Emma Diamond 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	Emma Diamond	Average
Overall Score	8.18	8.52
Price (Queen)	C$899	$1,524 (Hybrid only)
Cooling – Score	8.0	8.6
Sinkage – Depth	2.00″	2.25″
Sinkage – Feel	Moderate	Moderate
Motion Transfer – Score	9.6	8.2
Motion Transfer – Acceleration	5.93 m/s²	8.79 m/s²
Response Time – Score	9.1	8.8
Response Time – Mostly Recovered	0.3 sec.	0.4 sec.
Response Time – Fully Recovered	0.8 sec.	1.0 sec.
Bounce – Height	8.34″	8.68″
Bounce – Feel	Moderate	Moderate
Edge Support – Score	9.4	8.7
Edge Support – Sitting	3.25″	3.85″
Edge Support – Lying	Excellent	Good
Sex – Score	8.2	8.2
Pressure Relief – Score	7.0	8.6
Comfort Layer Thickness	2.00″	4.35″
Mattress Thickness	11.50″	12.30″
Off-Gassing – Score	2.2	7.9
Off-Gassing – Smell	Strong	Strong
Off-Gassing – Days	28 days	8 days
Company – Score	9.6	8.8
Trial	365 nights	191 nights
Warranty	15 years	40% have lifetime warranties, average of other 60% of mattresses is 13 years

How is Emma Diamond Different?

The Emma Diamond is a 11.50″ hybrid mattress with an overall performance level that is below average, but with a price that is also below average as well. This results in a value hybrid that is well-priced, as long as you are okay with the disadvantages.

Advantages

Advantages of the Emma Diamond include better motion isolation, faster material response time, better edge support, and an above-average company score.

Neutral Factors

This mattress has moderate levels of sinkage and bounce with a slight contour. These are all considered to be neutral factors since different sleepers may have different preferences.

The sex score is also right at the average level (8.2), making it a bit of a neutral factor as well.

Disadvantages

With the low price comes a handful of disadvantages. Pressure relief was well below-average in our tests, only scoring 7.0 out of 10 and with a 2.0″ comfort layer. This is 2.35″ thinner than average. The overall thickness is thinner as well, only 11.5″ thick where the average is 12.3″ thick.

Lastly, off-gassing is significantly slower than average, taking 28 days to fully dissipate, compared to the average duration of 8 days.

The Emma Diamond has good cooling. During our tests, I felt a slight to moderate level of heat retention around my body.

This mattress utilizes a hybrid design, which is helping to improve airflow into the mattress. In addition, we have a more limited comfort layer with just 2.0” of material.

That means there is less material in which heat could be easily retained. While these design attributes are helping the cooling equation, they are not enough. The specific foams used seem to struggle more with heat retention and the foams themselves don’t appear to breathe especially well.

• 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

The Emma Diamond is also equipped with a cool-to-the-touch cover. While it does have a very slight cooling feel, it loses what little cooling feel it has very quickly while lying on the mattress.

In our objective temperature tests, we measured a max surface level temperature of 92.4° F. This is 2.2° warmer than the average of 90.2° F, based on all of our tests to date.

After getting off the mattress, the temperature declined by 6.6 degrees from minutes 0 to 1, which is 1.8 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 Emma Diamond has moderate sinkage. During our tests, we measured a pressure point sinkage depth of 2.00″. This is 0.25″ less sinkage than the average sinkage depth of 2.25″, based on all of our tests to date. The mattress creates only a slight body contouring hug and has more of a floating feel.

The level of sinkage is documented in the image below.

The mattress creates a more buoyant feel where the body lies more “on” the mattress as opposed to sinking down “in” the mattress.

The Emma Diamond’s combination of less sinkage, floating / buoyant feel, and slightly firm feel (7 out of 10 in our tests, where 10 is the most firm) creates a more polarizing feel.

Some stomach and back sleepers could enjoy this feel, but I fear a majority of sleepers, especially most side sleepers, will not prefer this particular comfort and sinkage dynamic.

The Emma Diamond has a very low level of motion transfer. During our tests, we measured a total acceleration range of 5.93 m/s². This is 33% less motion transfer than the average of 8.81 m/s². This mattress has a lower level of bounce than average.

That lower bounce is the greatest single factor contributing to the lower level of motion transfer. Typically, mattresses with less comfort material struggle more with motion, but the Emma (which only has a 2.0” comfort layer) was able to maintain lower motion.

The coil unit seems to do a good job of isolating bounce, while also limiting it, both of which are contributing to the lower motion. In addition, the 0.75” memory foam layer is further helping to reduce and absorb energy.

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 0.2 seconds. Motion declines notably thereafter, but remains slightly spiky through 0.65 seconds.

By 0.65 seconds we’ve returned to near zero levels of energy, which is 0.25 seconds shorter than the average motion duration of 0.90 seconds.

Both motion duration and motion intensity are well below average. As a result, total motion transfer is fantastic. I expect most sleepers will find this level of motion more than satisfactory.

The Emma Diamond has a very fast mostly recovered response time and a fast fully recovered response time.

In our mostly recovered test, we measured a recovery speed of 0.3 seconds, which is 0.12 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 0.8 seconds, which is 0.22 seconds faster than the average of 1.02 seconds. While these material responsiveness speeds are far from instant, they are not slow either.

The level of responsiveness is documented in the video below.

The faster-than-average recovery speeds ensure the mattress is easy to move around on and won’t leave you feeling “stuck”. The fast responsiveness is further helped by the limited comfort layer and more restrained sinkage depth.

I expect most sleepers will find this level of material recovery speed to be satisfactory.

The Emma Diamond has a moderate level of bounce. During our tests, we measured a total bounce height of 8.34″. This is 0.35″ less bounce than the average of 8.69″, based on all of our tests to date.

Typically, hybrid mattresses with a thinner-than-average comfort layer would create more bounce, but that’s not what we measured here.

The Emma Diamond’s coil unit seems to simply not create as much bounce as many other coil units we’ve tested. In addition, the relatively dense memory foam layer is also likely absorbing and dispersing an outsized level of energy, further suppressing bounce.

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

The lower-than-average level of bounce is a major reason why motion transfer is lower. However, the lower bounce also has a negative impact on sex performance, so there are pros and cons worth considering.

The Emma Diamond has excellent sitting edge support and excellent lying edge support.

In our sitting edge support test, we measured a sitting sinkage compression of 3.25″. This is 0.60″ less sitting sinkage than the average of 3.85″, 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 excellent in all sleeping positions.

Emma Diamond is equipped with a reinforced support foam that runs along the entire perimeter of the mattress. Said foam is 4.5” wide and 7.5” tall. That’s quite a bit wider than what we typically see for edge support foam (when present, it tends to be around 3-3.5” wide).

Certainly, that wider-than-typical edge support foam is having the biggest impact on edge support.

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

In addition, the total feel of the mattress with its more restrained sinkage depth, slightly firm feel, and limited comfort layer are also factors contributing to the strong edge support.

The Emma Diamond has good sex performance. First up, let’s talk through the positives. The mattress has minimal noise, good enough cooling, and excellent edge support.

In our edge support tests, we measure a sitting sinkage compression of 3.25”. This is considerably better than average and helps to create robust support at the edge, extending the usable surface area.

Where the mattress isn’t so great for sex is pressure relief and bounce. Pressure relief earned a fair score due to the considerably thinner-than-average 2.0” height. More simply put, I did not find the mattress comfortable and that lack of comfort negatively impacts sex.

That said, the biggest negative sex factor is simply bounce. We measured just 8.34” of bounce. Emma Diamond has less bounce than average. The lower level of bounce makes sex more strenuous, tiring, and less fun.

Sex Factor	Factor Weight	Score	Rating
Bounce	65%	7.7	Moderate
Edge Support	20%	9.7	Excellent
Noise	5%	10	Minimal
Pressure Relief	5%	7.0	Fair
Cooling	5%	8.0	Good

Overall, sex performance is a mixed bag. The mattress earns an overall good score, but it’s also far from great.

The Emma Diamond has a fair level of pressure relief. During our tests, I felt notable pressure points on my body.

The mattress is equipped with 2.0″ of comfort material, which is 2.34″ less comfort material than the average comfort layer thickness of 4.34″, based on all of our tests to date.

The thinner-than-average comfort layer is the most significant reason for the lack of pressure relief. In our tests, we make a point to cut the mattress open to examine the material quality.

In doing so, I’m generally pleased with the quality of the foams, but the thickness is severely lacking.

You simply cannot create ideal pressure relief with a mattress that only has 2.0” of comfort material. Especially when those foams and coil unit are creating such resilient pushback, limited sinkage, and a restrained body contouring hug.

Overall, I simply found the mattress to be entirely uncomfortable.

Pressure Relief (PSI)	Average	Maximum
Side Sleepers	0.09	0.27

Pressure Relief (PSI)	Average	Maximum
Back Sleepers	0.06	0.35

Pressure Relief (PSI)	Average	Maximum
Stomach Sleepers	0.07	0.64

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 fair.

The Emma Diamond had a strong smell upon the initial unboxing. The mattress smelled for 28 days. This is 20.5 days longer than the average smell duration of 7.5 days.

Emma mattresses come with a 365-night trial period and a 15-year warranty. Shipping and returns are both free.

Company Factor	Factor Weight	Score	Data
Returns	40%	10	$0
Trial Period	30%	10	365 nights
Warranty	20%	8.0	15 years
Shipping	10%	10	$0
Country of Origin	0%		Thailand

Comparing 117+ brands tested to date, the average trial period is 191 nights, 174 nights less than Emma offers. The average warranty is 13 years, which is 2 years less than this mattress. This excludes the 42% of mattresses that offer lifetime warranties.

The Emma Diamond mattress is only available in one firmness option, which Emma describes as “Medium Plush” and for which Emma gives it a “3 out of 10” firmness rating.

My view on the firmness is dramatically different and I rate it as slightly firm feel, with a 7 out of 10 firmness, where 10 is the most firm.

This is one of the largest discrepancies between a brand’s description of their mattress and my personal rating I’ve seen yet.

In my view, this mattress is absolutely not a “medium plush” or anything anywhere close to that firmness.

Support on the Emma Diamond is fair. During our tests, I felt that support was okay while lying on my stomach or back, but entirely unsupported for side sleepers. To be clear, support was fair, but that is far from being great.

Support Factor	Data
Comfort Layer	2.00″
Support Layer	9.50″
Firmness	Slightly Firm
Body Contour	Slight
Zoned Support	Yes
Reinforced Edge	Yes

The mattress is equipped with a 9.5″ support layer. This is 1.55″ thicker than the average support layer thickness of 7.95″, based on all of our tests to date.

For a mattress to create ideal support, it must achieve two major requirements. First, it needs to support the body, maintaining a neutral spinal alignment. Second, it must provide sufficient comfort and pressure relief.

With respect to supporting the body, this mattress does support the body and is able to maintain a more neutral alignment on the back and stomach. That said, the limited sinkage depth and slightly firm feel are not ideal for side sleepers.

With respect to comfort and pressure relief, the mattress is also lacking. Emma Diamond utilizes only 2.0” of comfort material, which is significantly thinner than average. The lack of comfort material means pressure relief and comfort struggle, which makes it hard to lie in the same position for any extended period of time.

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	No	Yes
150-250 lbs.	Yes	No	Yes
250-300 lbs.	Yes	No	Yes

Moving on, this mattress has a slightly firm feel, 7 out of 10 in our tests. This firmness can be an okay choice for some stomach and back sleepers, but is not ideal for most side sleepers.

To be clear, Emma rates their firmness at a 3 out of 10 firmness and characterizes it as “medium-plush”. I completely disagree with Emma’s assessment of their firmness. There is nothing that is plush about this mattress. It is a typical slightly firm feel mattress.

Lastly, the mattress is equipped with a zoned coil unit. While it’s great to see zoned support, as it can help to improve support and reduce sagging, in this case it feels moot. The problems with the sinkage dynamic, pressure relief, and firmness create support issues that are not resolved by a zoned coil unit.

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 Emma Diamond is fair.

The Emma Diamond is a 11.50″ hybrid mattress that comes in a single firmness option—Slightly Firm. Within the Emma collection, the Diamond is designed as a tier above the Emma Body Adapt.

It has a thicker profile, although it still measures thinner in our tests (11.50″) than Emma describes (12.00″) on their website.

Design Factor	Data
Type	Hybrid
Thickness	11.50″
Cover Type	Thin
Weight	104 lbs.
Has Handles	Yes
Fiberglass-Free	Yes
Ships in a Box	Yes

It has a thin cover and a simple design, skipping bells and whistles that would otherwise drive up the price tag.

The Emma Diamond is 11.50″ thick and contains a combination of different foam types and coils. From top to bottom, here is a full list of the materials used in this mattress:

Layer Type	Thickness	Manufacturer’s Specs	Tested Specs
Poly Foam	0.75″	Not Available	2.08 PCF
Memory Foam	0.75″	Not Available	3.03 PCF
Poly Foam	0.50″	Not Available	1.64 PCF
Pocketed Coils (Interior), Poly Foam (Edge)	8.00″	Not Available	15.5 Gauge, 1.85 PCF
Support Foam	1.50″	Not Available	1.59 PCF

The Emma Diamond has a thin cover made of 69% polyesterice and 31% polyethylene.

Emma states that there is a cooling treatment on the cover with a “cool to the touch finish”, but the details are unclear. In our tests, cooling performed below average.

The comfort layer is 2.00″ thick and made of three thinner layers of foam. Directly below the cover is a 0.75″ poly foam, followed by a 0.75″ memory foam, and lastly a 0.5″ poly foam.

Together, this provides a 2.0″ comfort layer beneath the cover.

The support layer is 9.50″ thick and made of an 8.0″ pocketed coil system followed by a 1.5″ support foam base.

Product Evolution

The Emma Diamond is the newest model to the Emma Canada collection, replacing the Emma Performance (now discontinued).

In 2026, Emma Canada overhauled their entire collection, discontinuing all of their mattresses, with the new collection only including two mattresses—Emma Body Adapt (base level) and Emma Diamond (top tier).

For differences, you can read the Emma Body Adapt mattress review here.

Other Mattresses to Consider

Not sure if the Emma Diamond is the right pick for you? Check out these three other top-rated hybrid mattresses for alternatives you may want to consider.

Frequently Asked Questions

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