Intro to 32 Density vs 40 Density Foam
Polyurethane foam comes in a wide range of densities, with key options being 32-density and 40-density foams. But what exactly do these foam density numbers mean? And how do they impact factors like firmness, durability, and heat retention?
This in-depth guide covers everything you need to know about 32-density vs 40-density polyurethane foam.
What is Foam Density?
Foam density refers to the weight per cubic foot of foam, measured in pounds per cubic foot (PCF). The higher the foam’s density, the more weight and substance it contains in each cubic foot.
Higher-density foam also tends to feel more firm and supportive. Lower-density foam has a softer, cushiony feel.
Typical polyurethane foam densities range from 1.8 to 2.8 PCF on the low end, and up to 5.0 PCF or higher on the very high end. Popular densities for furniture and bedding include:
- Low density – 1.8 to 1.9 PCF
- Medium density – 2.5 to 4.0 PCF
- High density – Over 4.0 PCF
32-density and 40-density foams fall into the medium-density range. But there are some key differences between the two, explored next.
Overview of 32 Density Foam
32-density foam has a density of approximately 32 PCF. This puts it on the lower end of the medium-density spectrum.
Key Features of 32 Density Foam:
- Very plush, cushy feel
- Softer than higher-density foams
- Often used for cushioning in budget-friendly furniture
- More affordable option
- Tends to compress down and lose shape over time
- It is less supportive than high-density foam
- Can contribute to sagging in mattresses or furniture
The soft, almost pillow-like feel of 32-density foam makes it a popular choice for adding comfortable cushioning to furniture like couches and chairs. It conforms closely to the body for a “sinking in” sensation.
However, the lower density means 32-density foam does not provide the same level of sturdy support as higher-density options. It compresses down easily under body weight. Over time, this can lead to permanent indentations and sagging.
Overview of 40 Density Foam
40-density foam, as the name suggests, has a density of about 40 PCF. This puts it in the medium-high end of density levels.
Key Attributes of 40 Density Foam:
- Firmer, more supportive feel
- Increased durability and resilience
- Retains shape better than lower densities
- Bouncy, responsive texture
- Used in higher-end mattresses and upholstered furniture
- Usually more expensive than lower-density foams like 32-density
With its blend of comfort, support, and durability, 40-density foam is a popular choice for manufacturers of high-quality mattresses and sofas. It strikes a balance between cushioning comfort and sturdy support.
The slightly higher density gives 40-density foam better resilience against compression and indentation. It does not sink excessively under body weight. This helps it maintain its supportive structure twice as long as lower-density foams.
Density’s Impact on Foam Firmness
As a general rule, higher-density foam feels firmer, while lower-density foam feels softer. However, density is not the only factor determining a foam’s firmness.
The feel and firmness of foam depends on multiple variables, including:
- Density – Higher density contributes to a firmer feel.
- IFD/ILD rating – Specifically measures foam indentation force deflection for firmness.
- Foam type – Polyurethane, memory foam, latex foam, etc. have innate firmness.
- Quality – Better quality foam retains properties like firmness longer.
- Thickness – Thicker foam layers feel softer until fully compressed.
Among those factors, IFD/ILD is the most direct measurement of foam firmness. It quantifies the force (in pounds) required to indent the foam by 25% or 65%. Most foam manufacturers will provide IFD/ILD ratings.
As an example, let’s compare IFD ratings of 32 density vs 40 density polyurethane foam:
| Density | 25% IFD Range | 65% IFD Range |
|---|---|---|
| 32 Density Foam | 15-19 lbs | 34-40 lbs |
| 40 Density Foam | 24-32 lbs | 48-58 lbs |
The higher ILD ratings for 40-density PU foam demonstrate how it requires more force to achieve the same 25% and 65% indentations. This translates to a firmer lay and sit.
So while density contributes to perceived firmness, factors like IFD ratings better quantify true foam firmness.
Durability and Lifespan Impact of Density
Foam density also affects durability and lifespan. Due to its heavier, more compact cellular structure, higher-density foam tends to be more resilient and long-lasting.
- Low-density foam often starts exhibiting permanent indentations after 6 months to 1 year of use.
- Medium densities like 32 PCF and 40 PCF last 1-2 years before gradual softening.
- High-density foams maintain their original supportive properties for 3+ years in most cases.
However, all foam will eventually compress, soften, and lose some support over an extended period. Proper care is also essential for the foam’s longevity. Best practices include:
- Regular cleaning according to manufacturer guidelines
- Prompt spot treatment of stains and spills
- Rotating and fluffing cushions and mattresses
- Protecting foam from direct sunlight when possible
With optimal care, 32-density and 40-density foam can last 2-4 years before needing replacement. But higher-density foam generally outlasts lower densities given the same usage and care patterns.
Density and Heat Retention
People sometimes cite foam density as a key factor affecting heat retention and sleep temperature. But there are a few nuances around this topic.
On the whole, higher-density foam does tend to sleep slightly warmer. The denser, more compact cell structure tends to trap body heat rather than allow airflow through the foam.
However, this does not make density alone a reliable predictor of whether foam will sleep hot or cool. Other aspects like cell structure engineering, airflow channels, and phase change materials also heavily impact breathability.
For example: High-density open-cell memory foams often sleep cooler than lower-density closed-cell polyurethane foams. The cell structure and foam chemistry matter greatly.
Between 32-density and 40-density polyurethane foam specifically, the 40-density may sleep slightly warmer for some. However, the small density difference is unlikely to make a night and day difference in temperature regulation.
Choosing the Right Foam Density
So when should you choose 32-density or 40-density PU foam? Consider these usage guidelines:
32 Density Foam is best suited for:
- Adding soft cushioning comfort to furniture
- Budget sofas, chairs, and mattresses
- Situations that do not require as much support
- Lower-use guest beds, RVs, sleeper sofas
40 Density Foam works well for:
- Mattresses and seating meant for everyday use
- Providing better support for proper spinal alignment
- More durable furniture that retains its shape
- High-quality upholstered furniture and bedding
- People who prefer medium-firm to firm cushioning
Of course, density should not be the only deciding factor. But for general guidance:
- 32-density foam promotes affordability and cushioning softness
- 40-density foam optimizes support, durability, and performance
Density vs. Other Foam Qualities
Along with density, several other variables impact foam comfort, support, and durability. When comparing foams, also consider:
1. Foam Type
- Polyurethane
- Memory foam
- Latex foam
- Polyfoam
- HR polyurethane
2. IFD/ILD Rating
- Quantifies indentation force deflection as a measure of firmness
3. Cell Structure
- Open-cell vs closed-cell foam
- Impacts breathability, durability, density
4. Manufacturing Quality
- Quality control standards
- Testing and certifications
- Use of safer chemical ingredients
5. Thickness
- Total foam thickness
- Thicker foam layers generally feel softer
Evaluating these foam qualities alongside density provides a more complete picture of expected performance and durability.
Summary: 32 Density vs 40 Density Foam
32 and 40 density represent two of the most common polyurethane foam density options. Key differences include:
- Feel: 32-density foam has a softer, more cushiony feel. The 40-density foam feels firmer and more supportive.
- Cost: 32-density foam carries a more budget-friendly price tag in most cases.
- Durability: 40-density foam retains its supportive properties and shapes longer before permanent indentations set in.
- Uses: 32-density foam works well for lightly used furniture cushioning. 40-density is better suited for everyday mattresses and seating.
While density plays a key role, characteristics like foam type, ILD ratings, quality, and thickness also affect the ultimate comfort and performance. Evaluating these additional factors allows for a more informed foam comparison.