Review: Sleeping on Sleep Number’s True Temp cooling pillow

I test mattresses and pillows for a living — which is suitable career choice for someone who regularly grapples with with back injuries, grinds her teeth, and overheats like a car engine on a sweltering summer day. Consider me a modern-day Goldilocks, always searching for sleep products that feel “just right.”

So imagine my joy when I got to rest my weary head on the cooling, contoured, and customizable Sleep Number True Temp pillow(opens in a new tab) (from $109.99). If you’re balking at the price, I get it — why spend so much for a pillow? However, sleep is one of the most important investments you can make, especially since it impacts your overall health and wellbeing. 

After sleeping on a Sleep Number True Temp pillow for two weeks, I can confidently claim that it’s worth every penny. The tension in my shoulders melted away and I barely broke into a sweat. However, the most impressive takeaway is the marked improvement in my teeth grinding habit, which earned this pillow my orthodontist’s seal of approval. (One out of one orthodontists agree? Sure, let’s go with that.)

How I chose my Sleep Number True Temp pillow

To find my ideal Sleep Number pillow, I took a short quiz(opens in a new tab). As a side/stomach sleeper with loads of tension in my upper body, the results suggested I go for the True Temp Ultimate pillow. Although the quiz didn’t ask about temperature regulation, I was drawn to the the cooling properties of the True Temp pillow because I occasionally overheat at night. 

The Sleep Number True Temp pillow has three versions: 

• The Classic resembles a traditional pillow and caters to back and stomach sleepers. 

• The Contour has a groove in the middle to better support side and back sleepers. 

• The Ultimate is a customizable pillow with three removable foam inserts, allowing all types of sleepers to adjust the loft and feel as needed. 

Since I tend to sleep in multiple positions, the versatility of the Ultimate is likely why it was chosen as the greatest Sleep Number pillow for me.

The Sleep Number True Temp Ultimate pillow is customizable to fit all types of sleepers.
Credit: Alison Barretta / Mashable

What’s the Sleep Number True Temp pillow made of?

All Sleep Number True Temp pillows have a foam core, with the Ultimate version featuring three removable foam inserts: two flat slabs plus a dual-height ergonomic layer to suit the level of head and heck support you need. Spare inserts can be stored in the included travel bag. Sleep Number uses CertiPUR-US foams that are low in ozone-depleting emissions, and they won’t negatively impact indoor air quality, either.

The cover is a polyethylene and polyester blend that incorporates 37.5 Technology, which the brand says contains active particles of volcanic materials(opens in a new tab) to help the pillow adapt to your body’s ideal temperature and humidity levels. The tech’s cooling properties come from evaporative cooling, similar to the way your body sweats to keep you cool. The pillow feels cool to the touch and is designed to maintain that sensation even after it’s washed. (The cover is washable in cold water and can be tumble-dried on low heat; the foam inserts are spot-clean only.)

You’re able to add/remove layers of the Ultimate pillow.
Credit: Alison Barretta / Mashable

How the Sleep Number True Temp pillow changed my sleep in two weeks

My Sleep Number True Temp Ultimate pillow arrived in a cloth case, which can be used for travel or storing extra foam layers. After unpacking it, I immediately tested the pillow to determine if I needed to remove any layers. I’m primarily a side sleeper, so I based my ideal feel on that position. Fortunately, the default firmness and loft were perfect for me with no adjustments needed. However, your mileage will vary here, and if your sleep needs change frequently then expect to make regular adjustments.

I had been dealing with sore shoulders due to a lack of support from my previous shredded foam adjustable pillow. The contoured foam of the Sleep Number pillow neatly fit the nook between my chin and shoulder, and the two flat foam layers added the perfect amount of plushness. This resulted in less strain on my neck and shoulders when side sleeping, which in turn also helped reduce my teeth grinding because I was no longer sleeping on a pillow that was too high, a common cause of night bruxism(opens in a new tab).

The cooling sensation of the True Temp cover persisted for weeks after unboxing, even after washing it. I didn’t wake up with a sweaty nape or brow, regardless of how much I bundled up during some frigid March nights. Initially, I slept on the pillow on its own. During the second week I added a standard poly-cotton pillowcase. The extra layer of fabric didn’t limit the cooling abilities of the True Temp cover, but it slightly diminished the pillow’s contouring effect since the pillowcase wasn’t a tight fit. (It’s probably greatest to use one of Sleep Number’s pillow protectors(opens in a new tab).)

The Sleep Number True Temp pillow changed my sleep for the better, but there are some flaws.  A chemical-like odor lingered for a couple of days after unboxing. (This off-gassing is typical of foam bedding and though it’s generally harmless it’s still not pleasant.) Meanwhile, customizing the pillow is easy but finding the right combination of layers might take time. However, I wouldn’t recommend the True Temp Ultimate pillow for dedicated stomach sleepers. The ergonomic layer is too high and the flat foam slabs too soft, making it difficult to find the right balance. 

So did Sleep Number’s quiz make the right recommendation for me? Yes, it was on the money. (It also helps that I know exactly what I need in a pillow.) But it’s not a perfect system — trying a pillow for yourself is the greatest way to know if it’s the right one. Fortunately, Sleep Number offers a 100-night trial plus free returns or exchanges if you’re not satisfied.

Is the Sleep Number True Temp pillow worth it?

With a retail price between $110 and $180, this is an obvious (and fair) question to ask. Based on my experience, the Sleep Number True Temp Ultimate pillow is a sound investment for side or back sleepers seeking tailored support and pressure relief without the mess of shredded foam. Sleep Number’s use of 37.5 Technology might sound gimmicky, but the cooling cover offers exceptional temperature regulation, making it a great choice for anyone who sleeps hot.

But what do other sleepers think? The True Temp pillow scores high marks from Sleep Number customers, boasting a 4.6 stars out of 5 from nearly 3,000 reviews as of April 2023. Fans of the pillow like the soothing effects of the cooling cover, as well as the ease of customizing the loft and feel through the foam inserts. Like me, several Sleep Number shoppers claim their True Temp pillows alleviated their back and neck pain.

If you’re a dedicated stomach sleeper, the traditional (non-customizable) Sleep Number True Temp Classic pillow(opens in a new tab) may be a better fit. Alternatively, the more affordable Brooklinen Marlow pillow(opens in a new tab) (starting at $65) provides suitable comfort for front sleepers. It offers adjustable firmness and loft through a pair of zippers, eliminating the hassle of having to find storage for extra fill.

As for me, the Sleep Number True Temp Ultimate has become my go-to pillow. I find that it helps me fidget a lot less at night — more often than not I remain on my side since the contoured design is that comfortable. It’s also nice to wake up each morning without any nagging pain or puddles of sweat. Greatest of all, there’s no need to fluff it daily so if you’re as lazy or forgetful as I am, you’ll appreciate the minimal maintenance required for effectiveness.

UPDATE: Jun. 26, 2023, 4:35 p.m. EDT An earlier version of this review used the phrasing “Sleep Number’s proprietary 37.5 Technology.” However, 37.5 Technology is a third-party material supplier and is not owned by Sleep Number.