What is the Simba HeatRelease mattress collection?
You may well be searching for Simba HeatRelease mattresses, but these aren't actually stand-alone mattresses. Instead, HeatRelease is available as an upgrade to some of Simba's exisitng mattresses.
But what exactly is it?
HeatRelease is a graphite-infused cooling layer that Simba has engineered to sit alongside its existing Simbatex foam.
The idea is simple: Graphite is naturally good at conducting heat, so strips of it are used to actively pull excess body heat away from the sleeper rather than just letting a mattress passively breathe.
According to Simba, the technology gets to work within around 20 minutes of getting into bed and keeps working through the night. In lab testing, the brand found the upper foam layer of a Simba Hybrid Ultra mattress ran up to 4.4°C cooler with HeatRelease than without it, with that effect said to last up to 8 hours.
One of our UK testers, a naturally hot sleeper testing the HeatRelease mattress in the midsts of a UK summer heatwave, confirmed that the mattress remained cool and comfortable throughout the night.
Which Simba mattresses is HeatRelease available on?
The HeatRelease mattress isn't a standalone product.
Instead, it's built into or offered as an upgrade across three tiers of Simba's Hybrid range:
- Simba Hybrid Pro: HeatRelease available as an optional upgrade
- Simba Hybrid Luxe: HeatRelease available as an optional upgrade
- Simba Hybrid Ultra: HeatRelease included as standard
You'll need to choose the HeatRelease upgrade at an additioanl ££ cost if you want it as part of your Pro or Luxe mattress purchases, but it'll come standard with the Simba Ultra.
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![Simba Hybrid Pro]()
![Simba Hybrid Pro]()
Simba![Simba]()
Hybrid Pro MattressPrice from £ 899The best-selling Simba Hybrid Pro is the brand's second-generation hybrid mattress with a unique wool layer for enhanced temperature regulation."HeatRelease: Try the HeatRelease upgrade for sleep that's up to 4.4°C cooler."The best-selling Simba Hybrid Pro is the brand's second-generation hybrid mattress with a unique wool layer for enhanced temperature regulation."HeatRelease: Try the HeatRelease upgrade for sleep that's up to 4.4°C cooler."Price from £ 899 -
![Simba Hybrid Luxe]()
![Simba Hybrid Luxe]()
Simba![Simba]()
Hybrid Luxe MattressPrice from £ 1,249The Simba Hybrid Luxe is one of Simba's most advanced mattresses with 11 premium layers and a medium-firm feel."HeatRelease: Try the HeatRelease upgrade for sleep that's up to 4.4°C cooler."The Simba Hybrid Luxe is one of Simba's most advanced mattresses with 11 premium layers and a medium-firm feel."HeatRelease: Try the HeatRelease upgrade for sleep that's up to 4.4°C cooler."Price from £ 1,249 -
![simba hybrid ultra mattress]()
![simba hybrid ultra mattress]()
Simba![Simba]()
Hybrid Ultra MattressPrice from £ 1,749The Simba Hybrid Ultra is an 11-layer mattress with HeatRelease technology, designed for luxurious comfort, airflow, and advanced support.The Simba Hybrid Ultra is an 11-layer mattress with HeatRelease technology, designed for luxurious comfort, airflow, and advanced support.Price from £ 1,749
Who is the Simba HeatRelease mattress for?
Simba's HeatRelease is aimed squarely at hot sleepers, and particularly:
- People whose bedrooms struggle to stay cool overnight, especially in older UK homes with poor ventilation
- Anyone who already runs warm at night or finds themselves waking up overheated
- Couples where one partner tends to sleep hotter than the other
- Buyers who were already considering a Hybrid Pro or Luxe and want the extra temperature control
If you already sleep cool and comfortably, this is a nice to have rather than a must. The core Simba Hybrid mattresses without HeatRelease still use breathable Aerocoil springs and Simbatex foam, so you're not sleeping hot either way.
But if you're a naturally hot sleeper and desperate for some extra cooling, HeatRelease is a good way to go.
How does HeatRelease compare to Simba's existing cooling features?
Simba's mattresses were already designed with cooling in mind - the Aerocoil spring system encourages airflow, and Simbatex foam is graphite-infused for some heat conductivity.
HeatRelease builds on top of that rather than replacing it, adding a dedicated graphite strip layer whose only job is heat transfer, working in tandem with the existing foam and springs rather than instead of them.
For most sleepers, that should translate to a noticeably cooler surface temperature rather than a completely different sleep feel, since the underlying comfort and support layers (wool, foam, spring counts) stay the same as the non-HeatRelease versions of each mattress.
If you're still deciding on which mattress is right for you, visit our dedicated Simba Sleep mattress reviews (links below).
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![Simba Hybrid Pro]()
![Simba Hybrid Pro]()
Simba![Simba]()
Hybrid Pro MattressPrice from £ 899The best-selling Simba Hybrid Pro is the brand's second-generation hybrid mattress with a unique wool layer for enhanced temperature regulation."HeatRelease: Try the HeatRelease upgrade for sleep that's up to 4.4°C cooler."The best-selling Simba Hybrid Pro is the brand's second-generation hybrid mattress with a unique wool layer for enhanced temperature regulation."HeatRelease: Try the HeatRelease upgrade for sleep that's up to 4.4°C cooler."Price from £ 899 -
![Simba Hybrid Luxe]()
![Simba Hybrid Luxe]()
Simba![Simba]()
Hybrid Luxe MattressPrice from £ 1,249The Simba Hybrid Luxe is one of Simba's most advanced mattresses with 11 premium layers and a medium-firm feel."HeatRelease: Try the HeatRelease upgrade for sleep that's up to 4.4°C cooler."The Simba Hybrid Luxe is one of Simba's most advanced mattresses with 11 premium layers and a medium-firm feel."HeatRelease: Try the HeatRelease upgrade for sleep that's up to 4.4°C cooler."Price from £ 1,249 -
![simba hybrid ultra mattress]()
![simba hybrid ultra mattress]()
Simba![Simba]()
Hybrid Ultra MattressPrice from £ 1,749The Simba Hybrid Ultra is an 11-layer mattress with HeatRelease technology, designed for luxurious comfort, airflow, and advanced support.The Simba Hybrid Ultra is an 11-layer mattress with HeatRelease technology, designed for luxurious comfort, airflow, and advanced support.Price from £ 1,749
Our Simba Hybrid Pro HeatRelease mattress review
In order to try out HeatRelease, we tested the upgraded version of the Simba Hybrid Pro.
Like the standard Hybrid Pro, you'll get:
- Exceptional body-contouring support that's great for anyone after soft to medium-firm comfort
- A luxuriously-feeling mattress with a removable (and machine-washable) mattress cover
- Good motion isolation for calmer nights
- Free next-day room-of-choice delivery
- A risk-free 200-night trial with free returns
- A 10-year guarantee
Our mattress was delivered by a great team shortly after the order was placed, and we were kept updated at every point of the delivery process. The team was also super friendly, carrying the mattress up to the second floor and delivering to the room of choice.
Unpacking the mattress was quick and easy - flip the box on to the bed frame, roll the mattress out, carefully cut open the plastic cover, then remove the plastic and let the mattress return to its original size.
We did notice some off-gassing, which is normal for bed-in-a-box mattresses, but this disappeared within a few hours, and the mattress was ready to be slept on the same day.
As for comfort, our tester noted exceptional sleep - espcially since having moved over from an older IKEA mattress.
The Simba Hybrid Pro HeatRelease was comfortable, supportive, and cooling, which is worth writing home about since our tester is a naturally hot sleeper and testing took place during a UK heatwave.
Should you buy a Simba HeatRelease mattress?
If overheating at night is a genuine problem for you, HeatRelease is a reasonably priced way to tackle it without switching to a completely different mattress type.
It's worth noting the 4.4°C figure comes from Simba's own lab testing under controlled conditions, so real-world results indoors, on a warm night, will vary (as with any manufacturer's cooling claim).
As with all Simba Hybrid mattresses, the HeatRelease models come with a 200-night trial, so there's room to test it in your own bedroom before committing.
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![Simba Hybrid Pro]()
![Simba Hybrid Pro]()
Simba![Simba]()
Hybrid Pro MattressPrice from £ 899The best-selling Simba Hybrid Pro is the brand's second-generation hybrid mattress with a unique wool layer for enhanced temperature regulation."HeatRelease: Try the HeatRelease upgrade for sleep that's up to 4.4°C cooler."The best-selling Simba Hybrid Pro is the brand's second-generation hybrid mattress with a unique wool layer for enhanced temperature regulation."HeatRelease: Try the HeatRelease upgrade for sleep that's up to 4.4°C cooler."Price from £ 899 -
![Simba Hybrid Luxe]()
![Simba Hybrid Luxe]()
Simba![Simba]()
Hybrid Luxe MattressPrice from £ 1,249The Simba Hybrid Luxe is one of Simba's most advanced mattresses with 11 premium layers and a medium-firm feel."HeatRelease: Try the HeatRelease upgrade for sleep that's up to 4.4°C cooler."The Simba Hybrid Luxe is one of Simba's most advanced mattresses with 11 premium layers and a medium-firm feel."HeatRelease: Try the HeatRelease upgrade for sleep that's up to 4.4°C cooler."Price from £ 1,249 -
![simba hybrid ultra mattress]()
![simba hybrid ultra mattress]()
Simba![Simba]()
Hybrid Ultra MattressPrice from £ 1,749The Simba Hybrid Ultra is an 11-layer mattress with HeatRelease technology, designed for luxurious comfort, airflow, and advanced support.The Simba Hybrid Ultra is an 11-layer mattress with HeatRelease technology, designed for luxurious comfort, airflow, and advanced support.Price from £ 1,749
Contact Simba Sleep UK
Customer service: To contact Simba Sleep directly for complaints, support, or queries, please e-mail them at hello@simbasleep.com or visit their live online chat. The customer services team is available Monday to Friday, from 9 am - 5:0 pm., and Saturdays from 9 am to 1 pm.
Registered office: Simba Sleep, The Stable Yard, 60 Petty France, Westminster, London SW1H 9EU
Table of Contents
What is the Simba HeatRelease mattress collection?
Which Simba mattresses is HeatRelease available on?
Who is the Simba HeatRelease mattress for?
How does HeatRelease compare to Simba's existing cooling features?
Our Simba Hybrid Pro HeatRelease mattress review
Frequently asked questions
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Is HeatRelease aavailable outside the UK?
No, Simba has confirmed that HeatRelease is a UK-exclusive technology for now.
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Can I get HeatRelease on any Simba mattress?
Simba's HeatRelease is currently limited to the Hybrid mattress range, excluding the flagship Simba Hybrid. But you can get it as standard on the Hybrid Ultra, and as a paid upgrade on the Hybrid Pro and Hybrid Luxe.
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How much cooler does HeatRelease actually make a mattress?
Simba's lab testing found the upper foam layer ran up to 4.4°C cooler with HeatRelease than without, maintained for up to 8 hours under test conditions.
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Do HeatRelease mattresses come with a trial period?
Simba's HeatRelease upgrade mattresses come with the same 200-night trial as the rest of Simba's Hybrid range.
Alternatively, message us directly via the Contact Us page.