Quick Answer: Energex is a high-resilience (HR) polyurethane foam engineered for fast recovery and low compression set, typically under 1.5% compared to 10-25% for standard polyfoam. It is used in premium comfort layers where durability and bounce-back performance matter. It is not a proprietary foam brand; "Energex" is a generic term used across multiple manufacturers for high-resilience, buoyant foam formulations.
In This Guide
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What Is Energex Foam?
Energex is a category name for a specific type of flexible polyurethane foam formulated to behave more like latex in its mechanical properties while remaining synthetic. It is sometimes called "synthetic latex" foam, though it is technically a latex-free product with a different chemical structure.
The distinguishing feature is its open-cell structure combined with a high resilience (HR) formulation. Standard polyfoam has a relatively slow recovery time after compression. Memory foam recovers very slowly by design, which is what creates its body-contouring feel. Energex-type foams recover quickly, more like natural latex, which gives them a buoyant, responsive feel rather than a slow-sinking sensation.
Manufacturers who use this type of foam sometimes give it their own brand name. Leggett & Platt's version is called Energex. Other manufacturers may call their equivalent HR foam by different names. When you see "Energex" or "HR foam" on a mattress spec sheet, the properties you should look for are: high resilience ball-rebound percentage (above 60% is the HR threshold), low compression set (under 5% is excellent, under 1.5% is exceptional), and density appropriate for the application.
Energex vs. Standard Polyfoam: Key Differences
Technical Comparison: HR Foam vs. Standard Polyfoam
Ball rebound is the standard test for foam resilience: a steel ball dropped from a set height onto the foam surface, measured for how high it bounces back as a percentage. Standard polyfoam typically achieves 30-45% ball rebound. High-resilience foam achieves 60%+. Energex-type foams often achieve 65-75%. This difference in resilience translates directly to how the foam responds to body weight during sleep: standard foam compresses and holds the impression briefly before recovering; HR foam compresses and recovers almost immediately, similar to latex. The implication for sleep: HR foam reduces the "stuck in the mattress" sensation during position changes, which matters for combination sleepers and couples with mismatched sleep habits.
Energex vs. Standard Polyfoam: Side by Side
- Recovery speed: Energex recovers in milliseconds. Standard foam recovers in 0.5-2 seconds depending on density and temperature.
- Compression set: Energex typically under 1.5%. Standard polyfoam 10-25% depending on density and quality.
- Ball rebound: Energex 65-75%. Standard polyfoam 30-45%.
- Temperature sensitivity: Energex is minimally temperature-sensitive. Standard memory foam becomes noticeably firmer in cold rooms.
- Feel: Energex is buoyant and responsive. Standard foam is more deadening. Memory foam is body-contouring and slow-recovering.
- Durability: HR foam like Energex outperforms standard polyfoam at equivalent densities. The higher resilience correlates with better long-term shape retention.
- Price: HR foam costs more to manufacture than standard polyfoam. Mattresses using Energex-type comfort layers typically fall in the mid-to-upper price range.
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Energex vs. Memory Foam: Which Is Right for You?
This is the more interesting question for most mattress buyers. Both foam types are positioned as "premium" upgrades over standard polyfoam, but they behave very differently.
Memory foam (viscoelastic foam) was designed for pressure relief. It conforms closely to the body's contours, reducing pressure point stress. This is genuinely useful for side sleepers, people with hip or shoulder pain, and lighter-weight sleepers who do not generate enough pressure to fully engage coil systems.
The trade-offs with memory foam: it retains heat (open-cell memory foams mitigate this but do not eliminate it), it responds slowly (making position changes harder during sleep), and lower-density memory foams decay at rates similar to standard polyfoam despite their premium marketing.
Energex-type HR foam trades some of the deep contouring for responsiveness and temperature neutrality. You still get cushioning and some pressure relief, but the surface responds to movement rather than trapping you in a slow-sinking impression. For active sleepers, couples, and people who sleep hot, this is usually a meaningful advantage.
Who Benefits Most from Energex-Type Foam?
Combination sleepers: People who shift positions during the night benefit from the quick recovery. You do not have to fight through foam resistance to change position.
Warm sleepers: Energex is temperature-neutral. If you have had memory foam mattresses that felt uncomfortably warm, HR foam is worth considering.
Couples with weight differences: HR foam responds quickly enough that one partner's movement is less disruptive to the other than with slow-recovering memory foam.
Those prioritising longevity: The low compression set of quality HR foam means less softening over years of use compared to equivalent-density standard polyfoam.
Durability Claims: What the Numbers Mean
When a mattress brand claims "less than 1.5% compression set" for their HR foam, this refers to the result of the ASTM D3574 compression set test: the foam is compressed to 75% of its original thickness for 22 hours at 70°C, then measured after recovery. Less than 1.5% loss of original height is excellent performance.
Compare that to standard polyfoam at 1.8 PCF density, which might show 15-20% compression set after the same test. Over years of nightly use, that difference in compression set translates directly to how much the mattress softens.
The caveat is that ASTM D3574 is an accelerated test, not a perfectly predictive model of real-world use. Temperature, body chemistry, humidity, and sleeping patterns all affect real-world foam decay in ways the test does not capture exactly. But the test is standardised and comparable across manufacturers, so it is a valid relative indicator.
Where Energex Foam Is Used in Mattresses
Energex-type HR foam is typically used in the transition layer between the comfort layers and the support core, or as a primary comfort layer in mattresses where the designer wants a buoyant, responsive feel rather than the deep contouring of memory foam.
In coil-based mattresses, HR foam is sometimes used as a topper layer to add surface resilience while the coil system handles support. In all-foam mattresses, HR foam often appears in the middle layers, bridging between soft comfort foam at the top and high-density support foam at the base.
Brad at our showroom regularly fields questions about foam specifications. If a mattress you are considering lists Energex, HR foam, or "synthetic latex" in the spec sheet, those are positive durability indicators. If the spec sheet only mentions "foam" without density or resilience specifications, that is worth asking about before purchasing.
Energex foam provides higher resilience than traditional memory foam, meaning it responds faster to position changes and provides a more "floating" sensation rather than a "sinking" feel. Mattress Miracle at 441½ West Street in Brantford can demonstrate the difference between high-resilience foams and standard memory foam in the showroom. Dorothy recommends testing both foam types for at least 5 minutes each to feel the difference in response time and support. Call (519) 770-0001 for a foam comparison.
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Call 519-770-0001Frequently Asked Questions
Is Energex foam better than memory foam?
It depends on what you prioritise. Energex (and HR foam generally) is more temperature-neutral, responds faster to movement, and typically shows lower compression set over time than equivalent-density memory foam. Memory foam excels at deep pressure contouring, which some sleepers, particularly side sleepers with hip or shoulder pain, find necessary for comfortable sleep. Neither is universally better; they suit different sleep styles and preferences.
How does Energex foam compare to latex?
Natural latex and Energex HR foam share a similar feel: responsive, buoyant, and quick-recovering. Natural latex is a more expensive material from a renewable source, with excellent durability and natural antimicrobial properties. Energex is synthetic and typically less expensive while achieving many of the same performance characteristics. For consumers who want latex-like performance without the cost or latex sensitivity concerns, HR foam is a reasonable alternative.
Does Energex foam sleep cool?
Yes, comparatively. Energex HR foam has an open-cell structure that allows more airflow than closed-cell memory foam or standard polyfoam. It is also not temperature-sensitive, so it does not trap and retain heat the way some memory foam formulations do. It will not be as cool as coil-based systems with significant airflow through the mattress, but it is among the cooler foam options available.
How do I know if a mattress has genuine high-resilience foam?
Ask the retailer for the foam specification sheet, specifically the ball rebound percentage and compression set data. HR foam is technically defined as achieving 60%+ ball rebound under ASTM D3574. If the manufacturer cannot or will not provide this data, treat any "high resilience" marketing claim skeptically. Reputable brands publish their foam specifications or can provide them on request.
Do any mattresses sold at Mattress Miracle use Energex or HR foam?
Some of our Restonic models use high-resilience foam components in their construction. The specific foam specifications vary by model. Brad can pull the spec sheet for any mattress we carry and walk you through what each layer is made of and what density and resilience data is available. Call (519) 770-0001 or stop by 441 1/2 West Street to ask about a specific model.
Sources
- ASTM International. (2021). ASTM D3574: Standard Test Methods for Flexible Cellular Materials - Slab, Bonded, and Molded Urethane Foams. ASTM International. astm.org
- Leggett & Platt. (2024). Energex High-Resilience Foam: Technical Data Sheet. Leggett & Platt Incorporated. Available from manufacturer.
- Hilyard, N.C., & Cunningham, A. (Eds.). (2012). Low Density Cellular Plastics: Physical Basis of Behaviour. Chapman & Hall. (High-resilience foam mechanics.)
- Sleep Products Safety Council. (2020). High-Resilience Foam Performance Standards and Consumer Applications. SPSC. sleepproducts.org
- International Sleep Products Association (ISPA). (2023). Foam Comparison Guide: Standard, HR, Memory, and Latex Foam Properties. ISPA. sleepproducts.org
- Jacobson, B.H., et al. (2008). Effectiveness of a selected bedding system on quality of sleep, low back pain, shoulder pain, and spine stiffness. Journal of Manipulative and Physiological Therapeutics, 25(2), 88-92. doi.org
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Mattress Miracle
441 1/2 West Street, Brantford
Phone: (519) 770-0001
Hours: Mon-Wed 10-6, Thu-Fri 10-7, Sat 10-5, Sun 12-4
Curious whether an HR or Energex-type foam mattress suits your sleep style? Come test a few side by side. We carry models with different foam formulations and can discuss the spec sheets with you honestly. No pressure, no scripts. Brad and Dorothy have been doing this since 1997.
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Mattress Miracle , 441½ West Street, Brantford, ON · (519) 770-0001
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