HDPE vs. Polyethylene – Which Is Better?

Comparing high-density polyethylene (HDPE) vs. polyethylene (PE) affects everything, from installation to long-term performance. While both come from the same polymer family, their shared origins don’t mean they perform the same way.

In this guide, we’ll help you make cost-effective, durable choices by drawing on our experience in piping and construction. We’ll also provide a direct comparison of the two materials so you can determine which one best suits your project needs.

Polyethylene and HDPE: What Are They?

Polyethylene is a thermoplastic material made from ethylene gas. Meanwhile, HDPE is a variant of PE with a higher molecular weight. Although they have the same basic building blocks, HDPE is usually denser — and, thus, stronger and more rigid — than other types of polyethylene.

Note that polyethylene is used to refer to low-density polyethylene (LDPE), although the term actually refers to an entire family of thermoplastics.

PE vs. HDPE: How They Differ

This section explains all the crucial information about the properties of polyethylene and HDPE and how they affect products manufactured using these materials.

Durability

The density of PE greatly affects its durability because it determines how well the material can handle impact force or mechanical stress.

Low-density polyethylene (LDPE) is softer and more malleable, which is why it is less sturdy when subjected to mechanical stress. On the other hand, HDPE is stronger and sturdier due to having more packed and closely connected molecules.

Depending on how they are used, the project design, and the method of installation, HDPE pipes can even last between 50 and 100 years, making them the longest-lasting plastic pipes on the market.

Flexibility

PE is more flexible than HDPE because of its branched (and less dense) molecular structure. These branches make PE more flexible and better at absorbing impact than HDPE.

Because of its malleability, polyethylene is commonly used in food and beverage packaging (e.g., plastic wrappers and bottle caps), garden hoses, and kitchenware. Some pipes are also made of PE, particularly those used in cold water supply systems in residential areas.

Chemical Resistance

Polyethylene exhibits good chemical resistance against most acids, alcohols, bases, and esters. However, it can corrode when exposed for a certain time to:

• Oxidizing agents
• Mineral oils
• Aliphatic hydrocarbons

PE can also show immediate damage upon contact with mineral oils (at 50°C) and aromatic hydrocarbons.

On the other hand, HDPE has excellent chemical resistance, making it suitable for applications where exposure to acids, bases, and organic solvents is unavoidable. As such, many prefer HDPE pipes over PE.

Melting Point

LDPE has a lower melting point at 239°F (or 115°C). This low heat resistance makes the material ideal for heat sealing and injection molding.

However, if your project calls for something that can withstand higher temperatures, HDPE could be a better choice due to its higher melting point at 275°F (135°C).

HDPE vs. Polyethylene Pipes: Benefits and Applications

HDPE and low-density polyethylene pipes offer varying benefits, making them suitable for different applications.

HDPE

When comparing HDPE vs PE pipes, keep in mind that the former is more durable and rigid. It is also more reliable, has low thermal conductivity, and requires little maintenance, making it a cost-effective choice for most applications.

These advantages make HDPE pipes ideal for water, oil, and fuel transportation. They can also be used in food processing and other applications where the pipes come in contact with products for human consumption.

You may also find HDPE pipes for firefighting because of the material’s ability to withstand the level of water pressure required for the job.

PE

Although low-density polyethylene may not be as rigid as HDPE, it does have advantages when used in specific applications. Below are its top benefits:

• Flexible
• Lightweight
• Good mechanical strength
• Good chemical resistance

Low-density polyethylene’s low heat resistance makes it an excellent material for food packaging and plastic-melt sealing. It can also be used as insulation for underground utility lines and has specific medical applications (e.g., orthotics and prosthetics). Some drainage pipes can also be made from polyethylene.

FAQs

Below are quick answers to frequently asked questions about polyethylene and HDPE:

Which is better, polyethylene or HDPE?

As illustrated in this guide, the answer to this question depends on what you’re hoping to achieve:

• If your project requires flexibility or a low melting point, LDPE is a better choice.
• If you need a bit more durability and rigidity, as well as higher heat resistance, it’s best to use HDPE.

Is all polyethylene HDPE?

No. “Polyethylene” is an all-encompassing term for thermoplastic polymers within the same family. However, this term is also often used to refer to low-density polyethylene (LDPE), which is why some people may mistake it for a different type of polymer altogether.

Strictly speaking, there are several types of polyethylene, namely:

• Low-density polyethylene (LDPE)
• High-density polyethylene (HDPE)
• Medium-density polyethylene (MDPE)
• Linear low-density polyethylene (LLDPE)
• Ultra-high molecular weight polyethylene (UHMWPE)

The table below shows the distinct properties of each type.

What is HDPE suitable for?

HDPE has a wide range of applications, including:

• Water supply
• Drainage system
• Gas distribution
• Electrical conduit and cable insulation
• Consumer goods packaging (e.g., shampoo and beauty products)
• Food storage and containers
• Medical tubing
• Pharmaceutical packaging

HDPE is also a common plastic choice for toys, garden furniture, and home essentials, as well as pipes for construction.

Is HDPE the strongest plastic?

The lifespan of HDPE pipes, depending on their application, project design, and installation method, ranges from 50 to 100 years. This makes them one of the most durable plastic pipes available today.

Is HDPE more expensive than LDPE?

Yes, HDPE typically has a higher upfront cost than LDPE, but the full picture is more nuanced.

While LDPE is cheaper to produce and, thus, more affordable in the short term, HDPE offers greater cost-effectiveness over time.

HDPE provides excellent strength, durability, and resistance to impacts and chemicals, which means it lasts much longer, especially in tough applications like piping, containers, and construction materials. Plus, it’s even more recyclable than LDPE, helping to lower long-term waste management and environmental costs.

Which is better, HDPE or polypropylene?

Again, the answer depends on how you plan to use these materials. Although many of their properties overlap, they each have their own distinct benefits and ideal uses. For example:

• If your project calls for flexibility and a good strength-to-weight ratio, you’re better off using HDPE. This includes pipes and fittings, water and chemical storage, and squeeze bottles.
• If you plan to use plastic for high-temperature applications, opt for polypropylene. This material is highly recommended for automobile fenders and dashboards, and washing machine or dishwasher components.

Which One Should You Use?

The victor in the HDPE vs. polyethylene comparison will always depend on project demands. HDPE wins in strength, temperature resistance, and long-term durability, especially for high-pressure and industrial piping uses. Polyethylene, particularly LDPE, offers flexibility and cost-effectiveness for lighter applications.

Understanding these distinctions will help you pick the right material for your project without overengineering or overspending. Need expert help on your next project? Consult our plastic pipe experts at Polyfab to make the right choice.