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The three grades of polyfoam explained simply

Let's make this as simple as possible. There are three grades of polyfoam (polyurethane foam). You need to know them and here they are.

Grade 1: Conventional/Regular Polyfoam

  • Density: Under 1.5 lbs/ft³

  • Quality: Garbage

  • Verdict: AVOID

This is the cheap stuff. It's in almost every mainstream mattress because it's inexpensive to manufacture and it feels soft in the showroom. That's it... those are its only selling points.

Within months of regular use, conventional polyfoam starts breaking down. It loses its ability to bounce back. It softens unevenly. It develops impressions. It stops providing any meaningful pressure relief or support. Just do the thumbnail test on one and see for yourself how the dent you create stays there forever. Now imagine your body pressing on it nightly... Yep, flat within months.

The lowest of the low (under 1.2 lbs) shouldn't even be used in the cheapest throwaway mattresses. But you'll even find it in expensive beds because most consumers don't know to ask about density.

The ONLY acceptable use for conventional polyfoam is in thin quilting layers (about an inch or less) where foam softening has minimal impact on overall mattress performance.

If a salesperson can't tell you the density, or tells you "it's high-quality foam" without giving numbers, assume it's conventional polyfoam and act accordingly, which usually means walking away.

Grade 2: High Density Polyfoam (HD)

  • Density: 1.5 - 2.4 lbs/ft³ (I'd use 1.8 as the real minimum)

  • Quality: Acceptable to Good

  • Verdict: OKAY for comfort layers with caveats

High Density polyfoam is the middle grade. It's denser, more durable, and maintains its properties longer than conventional foam. It's an acceptable material in mattress comfort layers, especially for moderate budgets.

Some important notes:

  • The "official" threshold is 1.5 lbs, but I'd recommend 1.8 lbs as your minimum for one-sided mattresses. The extra density makes a real difference in durability.

  • If you're heavier (200+ lbs), push that minimum to 2.0 lbs or higher.

  • HD foam is more commonly available in firmer versions than softer ones. If you need soft comfort layers and can only find HD foam, it might be too firm for your needs.

  • In the support layers (the firm base of the mattress), HD foam is perfectly acceptable. Support layers aren't usually the weak link; comfort layers are.

HD polyfoam won't last as long as latex or HR polyfoam, but it's a reasonable material for mid-range mattresses. The key is knowing it's there and factoring that into your expectations.

Grade 3: High Resiliency Polyfoam (HR)

  • Density: 2.5 lbs/ft³ and up

  • Also requires: Support factor of 2.4+ and resilience of 60%+

  • Quality: Good to Excellent

  • Verdict: RECOMMENDED

This is the good stuff. HR polyfoam uses a different chemical formulation than conventional or HD foam, resulting in better cell structure, better durability, and better performance characteristics.

The best HR foams approach latex in their properties, which naturally have good resilience (springs back well), good progressive resistance (gets firmer as you press harder), and excellent durability. Some manufacturers claim 10+ years of useful life from quality HR foam.

Why don't more mattresses use it?

Cost. HR foam is more expensive to manufacture than conventional or even HD foam. It cuts into profit margins. So major manufacturers reserve it for their most expensive models, if they use it at all.

You're more likely to find HR foam in mattresses from smaller local/regional manufacturers who prioritize materials over marketing budgets.

The mislabeling problem

HR polyfoam is one of the most mislabeled materials in the industry.

Legally, foam must meet THREE criteria to be called HR:

  1. Density of 2.5 lbs/ft³ or higher

  2. Support factor (compression modulus) of 2.4 or higher

  3. Ball rebound (resilience) of 60% or higher

What often happens is that a manufacturer uses 2.5 lb foam and calls it "HR," even though it doesn't meet the support factor or resilience requirements. Technically illegal, but enforcement is basically non-existent.

The foam might be durable (because of the higher density), but it won't have the same performance characteristics as true HR foam. You're getting HD-quality performance at HR marketing prices.

This is why asking "is it HR foam?" isn't good enough. You need to ask for the specific density AND support factor. If they can't provide both numbers, be skeptical.

How to use this information?

When shopping for a mattress, get the specs on every foam layer:

  1. What type of foam is it? (polyfoam, memory foam, latex)

  2. What's the density?

  3. For polyfoam: is it true HR with a support factor of 2.4+?

Then compare to these guidelines:

  • Conventional polyfoam (under 1.5 lb): Only acceptable in thin quilting layers

  • HD polyfoam (1.5-2.4 lb): Acceptable for comfort layers; use 1.8 lb minimum

  • HR polyfoam (2.5+ lb with 2.4+ support factor): Recommended for any layer

The hierarchy matters for comfort layers

From most to least recommended for comfort layers:

  1. Latex (any)

  2. True HR polyfoam

  3. HD polyfoam (1.8 lb+)

  4. Memory foam (5 lb+) - different pros/cons

  5. HD polyfoam (1.5-1.8 lb)

  6. Memory foam (4-5 lb)

  7. Everything else

For support layers/cores:

  1. Latex

  2. Quality innersprings

  3. HR polyfoam

  4. HD polyfoam (2.0 lb+)

  5. Lower HD polyfoam

The support core doesn't matter as much because it's rarely the failure point. Focus your attention and budget on the comfort layers.

TL;DR

Three grades. Conventional = bad. HD = acceptable. HR = good.

Don't buy any mattress without knowing which grade of foam is in the comfort layers. It's the single biggest predictor of how long your mattress will actually last.

7Score: 7

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