At Essex Tubes, we work with cardboard every day, manufacturing cardboard tubes, cardboard cores, and postal tubes used across dozens of industries. One question we’re often asked is whether cardboard has insulating properties. The answer might surprise you.
Insulation is important because it not only prevents heat loss in the wintertime but also saves money by lowering heating costs in homes. People may be surprised if you were to suggest cardboard since it is commonly known to be used for mailing tubes, cardboard boxes and more.
If you’re interested in saving money as a homeowner, it’s impossible to ignore the benefits of maximising how efficient insulation can be for your home.
In this article, we will be looking at just how good cardboard is for insulation and how efficient it can be both practically, economically and environmentally.
Is Cardboard a Good Insulator? Quick Summary
| Property | Cardboard’s Performance |
|---|---|
| Thermal conductivity | Low — slows heat transfer effectively |
| Heat blocking | Good — useful as a temporary barrier |
| Heat trapping | Good — layered structure retains warmth |
| Moisture resistance | Poor — susceptible to mould and water damage |
| Cost-effectiveness | Moderate — cheap short-term, not ideal long-term |
| Environmental impact | Excellent — recyclable and biodegradable |
The power of wood
The use of wood as a building material is due to its insulating properties. Wood, being dense and fibrous in structure, transfers heat slowly, which makes it an excellent thermal barrier during winter months when other materials like metal or plastic have the opposite effect on temperature regulation.
Corrugated cardboard also benefits from these qualities because of how thinly cut the layers are; with less space between them, there’s more restriction for spreading out energy over time, thus retaining warmth within the envelope that may otherwise escape through convection currents created by high-speed winds outside such structures.
This same layered, fibrous structure is exactly what makes cardboard tubes and cardboard cores so robust. At Essex Tubes, our cardboard tube products are wound from recycled fibreboard layered tightly together, which not only gives them their strength and durability but also contributes to their natural insulating properties. It’s why industries such as construction, textiles, and film production rely on our industrial cardboard tubes for protecting temperature-sensitive materials during storage and transit.
Cardboard’s ability to block heat
Materials with a low thermal conductivity, like cardboard, are perfect for making insulation. These are used to keep heat from transferring between objects or locations.
A good example of this is when faced with a window being broken and left without replacements on hand.
Normally, it may seem like an impossible task to try and stop heat from being lost, but there’s one material around most homes…cardboard!
It is important to be creative in a situation where you may not have all the materials that are required. A piece of cardboard can act as insulation for the window by covering up any openings or gaps between pieces of glass.
This cardboard is a sturdy solution for the broken window. It keeps out cold and hot air, which will make your home more comfortable no matter what time of year it may be!
This heat-blocking quality is also why cardboard tubes are trusted for packaging and postal applications. The layered walls of a postal tube help protect contents from external temperature fluctuations during delivery. If you’re looking for postal tubes or mailing tubes for sensitive items, Essex Tubes’ range of stock postal tubes is available in sizes from A3 to B0, with next working day delivery to the UK mainland.
Cardboard’s ability to trap heat
Another brilliant effect of cardboard as an insulator is that heat can be trapped as well.
One example of this is not necessarily for keeping a house interior warm, but instead for cooking, by using a solar oven.
By using a cardboard box and adding some reflective material to the inside, you are able to trap heat from the sun.
Because cardboard doesn’t allow heat to transfer easily, it makes it ideal for allowing heat to remain within the DIY solar oven and therefore, makes it possible to cook things, although it will take some time.
Cardboard tube walls work on a similar principle. The layered cardboard core traps air between its wound layers, creating a natural barrier. This is one reason our bespoke cardboard cores are chosen for packaging fragile or sensitive industrial materials, where maintaining stable conditions matters.
How long does it last?
If you’re considering using cardboard for insulation, it’s important to keep in mind that due to its vulnerability and inconsistency when exposed long-term the material can have a variety of drawbacks.
The sturdy yet sensitive nature of cardboard makes it susceptible to mildew when in contact with moisture, such as humidity. When this occurs, you may notice the cardboard becoming mouldy or breaking apart completely due to water damage.
Mould can then cause unpleasant odours within a house, which could potentially harm anyone who lives inside it too!
Here’s a quick overview of cardboard’s key durability considerations:
- Moisture exposure — Cardboard degrades quickly when damp, making it unsuitable for long-term or outdoor insulation use
- Mould risk — Humid conditions can cause mould growth, which poses health risks if left untreated indoors
- Compression over time — Cardboard loses density under sustained pressure, reducing its insulating effectiveness
- Temperature extremes — Prolonged exposure to very high heat can cause cardboard to dry out, warp, or become a fire risk
It’s worth noting that, in contrast, Essex Tubes’ cardboard tube products are manufactured to exceed standard packaging industry requirements for durability. Our cardboard cores and tubes undergo rigorous quality control testing to ensure they withstand the demands of industrial use. From void former tubes used in motorway construction, to piling tubes used in groundwork projects where structural integrity is critical.
Is it cost-effective?
Cardboard insulation is a great way to make your home more comfortable. The material itself provides some degree of insulation, but it’s unlikely that this amount will result in enough savings on energy bills for the cost-effectiveness factor to be worth it.
The surface area of a material is often the best way to judge if it can be an effective insulator. In order for this property, materials must cover most or all of any given surface and maintain their density throughout.
It’s because of this that while cardboard can be a good insulator, it is not necessarily the best option if you’re looking for a way to save money on energy bills. Instead, investing in long-lasting, specific insulation material is the best option.
Is it beneficial for the environment?
While cardboard may be a good insulator, especially as a temporary fix, we’ve established that it is unlikely to last long and is not the most cost-effective way to insulate your home.
That being said, when it comes to being beneficial for the environment, you can argue that it is very efficient. This is because you are utilising a material that can be easily repurposed for other purposes, including a wide range of sustainable packaging solutions that reduce waste and minimise environmental impact.
Commonly, cardboard is very easily disposable, and while it can be recycled, using it in this way is particularly beneficial because it can avoid the use of things like electricity.
Of course, long-term, as previously mentioned, it will only be useful if the insulation is of the same density maintained across a surface.
At Essex Tubes, environmental responsibility sits at the heart of what we do. All of our cardboard tubes and postal tubes are made from 100% recycled fibreboard and are fully recyclable, so whether you’re using a cardboard mailing tube once for a postal delivery or relying on industrial cardboard cores for long-term production runs, you can be confident that Essex Tubes products leave minimal environmental impact.
As you can see, cardboard is clearly a useful material when it comes to insulation, and it is certainly something that can get you out of a worrying situation.
However, despite it being a good insulator, it is not accurate to say that it should be used as the basis for insulation across all homes; it is best as a temporary solution.
Frequently Asked Questions
Is cardboard a good insulator of heat?
Cardboard is a reasonable insulator of heat thanks to its low thermal conductivity and layered fibrous structure, which slows the transfer of heat. However, it is best considered a short-term or emergency solution rather than a permanent insulation material, as it is vulnerable to moisture and loses effectiveness over time.
Why does cardboard keep things warm?
Cardboard keeps things warm because its layered structure traps air, and air is a poor conductor of heat. This means heat transfer is slowed significantly, helping to retain warmth. The same principle applies to cardboard tubes. The wound layers of recycled fibreboard create a naturally insulating wall around whatever is stored or shipped inside.
Is cardboard better than plastic as an insulator?
In most cases, yes. Cardboard has a lower thermal conductivity than many plastics, meaning it slows heat transfer more effectively. It is also biodegradable and recyclable, making it the more environmentally responsible choice, which is why Essex Tubes manufactures all products from 100% recycled fibreboard with no chemical waste.
What are cardboard tubes used for?
Cardboard tubes have a huge range of applications. At Essex Tubes, we supply cardboard tubes and cores for postal and mailing use, industrial reel centres for textiles and paper, construction piling tubes, void formers for motorway projects, display tubes for shop windows and film sets, and bespoke custom tubes for specialist requirements. Diameters range from 34mm to 656mm, with lengths up to 13 metres.
Are cardboard tubes recyclable?
Yes. All Essex Tubes cardboard tubes and postal tubes are made from 100% recycled materials and are fully recyclable at the end of their life. We are a completely eco-friendly manufacturer with no chemical waste in our production process.
Can cardboard tubes be used outdoors or in damp conditions?
Standard cardboard tubes are not recommended for prolonged exposure to moisture, as cardboard degrades when damp. If you have a specialist requirement for tubes that need to withstand outdoor or wet conditions, get in touch with the Essex Tubes team, and we can advise on the best solution for your project.
Need Cardboard Tubes for Your Business or Project?
Whether you need standard postal tubes, bespoke cardboard cores, or heavy-duty industrial tubes, Essex Tubes has been manufacturing high-quality cardboard tube products since 1989. We supply businesses across the UK with tubes ranging from 34mm to 656mm in diameter and up to 13 metres in length.
Get in touch with our team today to request a quote, or visit our shop to browse our full range of postal tubes and mailing tubes available for next working day delivery.