Choosing the right ceiling insulation is one of the most important decisions homeowners in South Africa can make to improve comfort and reduce energy costs. With the intense summer heat and cold winter nights experienced in many parts of the country, proper insulation can dramatically improve indoor living conditions. For this reason Aerolite vs Isotherm Insulation page will give homeowners a guide to make the right choice.
Two of the most popular ceiling insulation products available in South Africa are Aerolite insulation and Isotherm insulation. Both products are widely used in residential and commercial buildings, but they are manufactured from different materials and offer slightly different benefits.
Understanding the differences between Aerolite and Isotherm insulation can help homeowners make the best decision for their home, budget and insulation needs.
In this guide, we will compare these two leading insulation options to determine which product performs best in different situations.
Table of Contents
Quick Comparison Table Aerolite Insulation vs Isotherm
| Feature | Aerolite Insulation | Isotherm Insulation |
|---|---|---|
| Material | Fibreglass | Polyester Fibre |
| Fire Rating | Non-combustible | Self-extinguishing |
| Thickness Options | 50mm – 135mm | 100mm – 145mm |
| Lifespan | 50+ years | 30 – 40 years |
| Moisture Resistance | Good | Excellent |
| Acoustic Insulation | Very good | Good |
| Environmental Impact | Manufactured from recycled glass | Manufactured from recycled PET plastic |
| Installation | Easy | Easy |
| Typical Application | Homes & commercial buildings | Homes & eco-friendly buildings |
What Is Aerolite Insulation?
Aerolite insulation is a fibreglass ceiling insulation manufactured from extremely fine glass fibres bonded together to create lightweight insulation rolls.
Fibreglass insulation has been used worldwide for many decades and is considered one of the most reliable and cost-effective insulation materials available.
Aerolite insulation works by trapping millions of tiny air pockets within the glass fibre structure. These air pockets slow down heat transfer, preventing heat from entering the house during summer and escaping during winter.
Aerolite insulation is widely installed in:
• Residential homes
• Commercial buildings
• Offices
• Schools
• Industrial buildings
Because of its excellent fire resistance and strong thermal performance, Aerolite has become one of the most trusted ceiling insulation products in South Africa.
For available sizes and thickness options, see: Aerolite Insulation Products
FREQUINTLY asked questions (FAQ'S0
Is Aerolite better than Isotherm insulation?
Both products offer similar insulation performance. Aerolite has stronger fire resistance while Isotherm is made from recycled polyester fibres.
Which insulation keeps houses cooler?
Both Aerolite and Isotherm insulation effectively reduce heat transfer through the roof, helping keep homes cooler during summer.
Does Aerolite insulation last longer?
Fibreglass insulation like Aerolite can last more than 50 years if installed correctly and kept dry.
Does Isotherm insulation cause itching?
No. Unlike fibreglass insulation, Isotherm insulation does not contain glass fibres and is generally non-irritating to handle.
Can I install insulation myself?
While DIY installation is possible, professional installation ensures proper coverage and maximum insulation performance.
How thick should ceiling insulation be in South Africa?
Most homes benefit from insulation thickness between 100mm and 135mm depending on the climate zone.
What Is Isotherm Insulation?
Isotherm insulation is a polyester fibre insulation manufactured from recycled plastic fibres. The material is similar to the fibres used in many modern textiles and clothing products.
Unlike fibreglass insulation, Isotherm insulation does not contain glass fibres. Instead, it uses a dense network of polyester fibres that trap air to reduce heat transfer.
Isotherm insulation is often marketed as a more environmentally friendly insulation option because it is made from recycled PET plastic.
Common applications for Isotherm insulation include:
• Residential homes
• Eco-friendly buildings
• Renovations
• Ceiling retrofits
For product options and available thicknesses, see: Isotherm Insulation Product Page
Thermal Performance Comparison
Thermal insulation performance is usually measured by its R-Value. The R-value indicates how effectively a material resists heat transfer.
Higher R-values provide better insulation performance.
Both Aerolite and Isotherm insulation offer similar thermal performance when installed at comparable thickness levels.
Typical R-values:
Aerolite 135mm
R-Value approximately 3.38 installed R-value 3.78
Isotherm 145mm
R-Value approximately 3.33 installed R-value 3.73
While Isotherm insulation often advertises a slightly higher R-value, the real-world performance difference between the two products is usually very small when installed correctly.
Both insulation types can significantly reduce heat transfer through the roof and improve indoor temperature control.
Isotherm Insulation Prices
What Is Isotherm Insulation?
Isotherm insulation is a polyester fibre insulation manufactured from recycled plastic fibres. The material is similar to the fibres used in many modern textiles and clothing products.
Unlike fibreglass insulation, Isotherm insulation does not contain glass fibres. Instead, it uses a dense network of polyester fibres that trap air to reduce heat transfer.
Isotherm insulation is often marketed as a more environmentally friendly insulation option because it is made from recycled PET plastic.
Common applications for Isotherm insulation include:
• Residential homes
• Eco-friendly buildings
• Renovations
• Ceiling retrofits
For product options and available thicknesses, see: Isotherm Insulation Product Page
Thermal Performance Comparison
Thermal insulation performance is usually measured by its R-Value. The R-value indicates how effectively a material resists heat transfer.
Higher R-values provide better insulation performance.
Both Aerolite and Isotherm insulation offer similar thermal performance when installed at comparable thickness levels.
Typical R-values:
Aerolite 135mm
R-Value approximately 3.38 installed R-value 3.78
Isotherm 145mm
R-Value approximately 3.33 installed R-value 3.73
While Isotherm insulation often advertises a slightly higher R-value, the real-world performance difference between the two products is usually very small when installed correctly.
Both insulation types can significantly reduce heat transfer through the roof and improve indoor temperature control.
THERMAL PERFORMANCE COMPARISON
Thermal insulation performance is usually measured by its R-Value. The R-value indicates how effectively a material resists heat transfer.
Higher R-values provide better insulation performance.
Both Aerolite and Isotherm insulation offer similar thermal performance when installed at comparable thickness levels.
Typical R-values:
Aerolite 135mm
R-Value approximately 3.38 installed R-value 3.78
Isotherm 145mm
R-Value approximately 3.33 installed R-value 3.73
While Isotherm insulation often advertises a slightly higher R-value, the real-world performance difference between the two products is usually very small when installed correctly.
Both insulation types can significantly reduce heat transfer through the roof and improve indoor temperature control.
FIRE SAFETY COMPARISON
Fire resistance is an important factor when selecting insulation materials.
Aerolite insulation is non-combustible, meaning it does not burn and does not contribute fuel to a fire. This makes fibreglass insulation a very safe option in buildings.
Isotherm insulation is self-extinguishing, which means it will not easily sustain a flame once the heat source is removed.
Although both products meet building safety standards, fibreglass insulation generally has a slight advantage in fire resistance.
Moisture Resistance
Roof spaces often experience moisture from condensation or small roof leaks.
Isotherm insulation performs very well in moist environments because polyester fibres do not absorb water easily.
Aerolite insulation can also handle moisture well, but may lose some insulation efficiency if it becomes heavily saturated.
In most residential installations where the roof is properly waterproofed, both insulation types perform well.
Acoustic Insulation
Ceiling insulation also helps reduce noise entering the home from outside sources such as rain, wind and traffic.
Aerolite insulation generally provides better acoustic insulation because fibreglass fibres absorb sound very effectively.
Homes near busy roads or in high rainfall areas may benefit from the sound-dampening properties of fibreglass insulation.
Environmental Impact
Many homeowners today consider the environmental impact of building materials.
Isotherm insulation is manufactured from recycled PET plastic, making it a popular option for environmentally conscious homeowners.
Aerolite insulation also uses recycled glass during manufacturing, but the production process is more energy-intensive.
Both products contribute to energy efficiency by reducing heating and cooling energy consumption in homes.
Installation Comparison
Both Aerolite and Isotherm insulation are supplied in roll form, which makes installation relatively simple.
Installation normally involves:
-
- Laying insulation rolls between ceiling joists
- Ensuring full coverage across the ceiling
- Avoiding compression of the insulation material
- Maintaining ventilation within the roof space
Correct installation is essential for achieving the best insulation performance.
Professional installation ensures the insulation is fitted correctly and complies with building standards.
Price Comparison
Pricing can vary depending on thickness, brand and supplier, but Aerolite insulation is generally slightly more affordable than Isotherm insulation.
Fibreglass insulation has been produced at large scale for decades, which helps keep manufacturing costs lower.
Isotherm insulation tends to be slightly more expensive due to its specialised polyester fibre manufacturing process.
For current pricing, see: Ceiling Insulation Prices South Africa
Which Insulation Is Better?
Both Aerolite and Isotherm insulation offer excellent thermal insulation for South African homes.
Aerolite insulation is often preferred for:
• Strong fire resistance
• Proven long-term performance
• Lower cost
• Excellent acoustic insulation
Isotherm insulation is often chosen for:
• Recycled environmentally friendly materials
• Soft non-itch fibres
• Good moisture resistance
For most homes, the performance difference between the two products is small. The final decision often comes down to budget and personal preference.
Our Recommendation
For homeowners looking for reliable and cost-effective ceiling insulation, Aerolite insulation remains one of the most widely used and trusted insulation products available.
However, Isotherm insulation also provides excellent insulation performance and is particularly attractive for environmentally conscious building projects.
For a complete overview of insulation options available in South Africa, see:
Best Ceiling Insulation in South Africa or Ultimate Guide to Roof Insulation