Armaflex vs Tubolit: Which Pipe Insulation Should You Choose?

June 7, 2026

What Is Armaflex EVO?

Armaflex EVO is a flexible closed-cell elastomeric foam pipe insulation manufactured by Armacell. It features a built-in vapour barrier (μ ≥ 10,000), Class O fire rating, Microban antimicrobial protection and a thermal conductivity of λ ≤ 0.033 W/mK. It is the most widely specified elastomeric foam pipe insulation in the UK for commercial HVAC, chilled water, heating and refrigeration applications.

Shop Armaflex EVO · Armaflex EVO Guide

What Is Tubolit?

Tubolit is a polyethylene foam pipe insulation manufactured by Armacell — the same manufacturer as Armaflex. It is an open-cell foam, available in standard (slit) and self-adhesive versions, and is widely used for basic domestic frost protection and heat loss reduction on heating and hot water pipework. It is the standard "grey foam lagging" sold in DIY stores across the UK.

Unlike Armaflex EVO, Tubolit does not have a built-in vapour barrier and is not suitable for condensation-critical applications such as chilled water or refrigeration pipework.

Armaflex vs Tubolit — Quick Comparison

Property	Armaflex EVO	Tubolit
Material	Closed-cell elastomeric foam	Open-cell polyethylene foam
Thermal conductivity	λ = 0.033 W/mK	λ = 0.038–0.040 W/mK
Vapour barrier	Built-in (μ ≥ 10,000)	None
Condensation control	Yes — closed cell	No — open cell
Fire rating	Class O, B-s2,d0	Class 1 (BS 476)
Operating temperature	-50°C to +105°C	-50°C to +85°C (approx)
Microban protection	Yes	No
Typical application	Commercial HVAC, chilled water, heating	Domestic heating, frost protection
Relative cost	Higher	Lower

Thermal Performance: Armaflex vs Tubolit

Armaflex EVO achieves λ = 0.033 W/mK, compared with approximately λ = 0.038–0.040 W/mK for Tubolit polyethylene foam. This means Armaflex EVO provides better thermal performance per millimetre of wall thickness — particularly relevant on commercial systems where BS 5422 compliance is required.

For domestic heating and hot water pipework in heated spaces, the difference in thermal performance between 13mm Armaflex and 13mm Tubolit is relatively small in practice. For commercial HVAC and chilled water applications, Armaflex EVO is the correct specification.

Condensation Control: The Critical Difference

This is the most important difference between the two products for many applications.

Armaflex EVO is a closed-cell foam with a built-in vapour barrier (μ ≥ 10,000). When all joints are properly sealed with Armaflex 520 adhesive, it forms a continuous vapour barrier that prevents condensation from forming on cold pipework.

Tubolit is an open-cell polyethylene foam. It has no vapour barrier and will not prevent condensation on chilled water or refrigeration pipework. Moisture will pass through the foam and condense on the cold pipe surface, leading to dripping, corrosion and insulation degradation over time.

For any chilled water, refrigeration or condensation-critical application, Armaflex EVO is the only correct choice. Tubolit must not be used on cold pipework where condensation control is required.

Fire Rating: Armaflex vs Tubolit

Armaflex EVO achieves Class O (BS 476 Part 6 & 7) and Euroclass B-s2,d0 — the standard fire rating required for commercial HVAC pipe insulation specifications in the UK.

Tubolit achieves Class 1 (BS 476 Part 7) — a lower fire classification that is acceptable for domestic applications but does not meet the Class O requirement specified for commercial HVAC systems.

For any commercial project where Class O pipe insulation is specified, Armaflex EVO is required. Tubolit is not suitable for commercial HVAC specifications.

When to Choose Armaflex EVO

Any commercial HVAC or building services application
Chilled water and refrigeration pipework — condensation control is essential
Heating and hot water pipework where Class O fire rating is specified
Applications requiring Microban antimicrobial protection (healthcare, food processing)
Any application where BS 5422 compliance is required

When to Choose Tubolit

Basic domestic frost protection on heating and hot water pipes
Domestic heating pipework in heated spaces where Class O is not required
Budget-conscious domestic installations where condensation control is not needed
Temporary or short-term pipe protection

Cost Comparison: Armaflex vs Tubolit

Tubolit is generally the lower-cost option and is commonly selected for domestic heating pipework where only basic heat loss reduction or frost protection is required.

Armaflex EVO commands a higher purchase price because it provides superior thermal performance, a built-in vapour barrier, Class O fire performance and Microban antimicrobial protection.

For commercial HVAC systems, chilled water applications and projects requiring BS 5422 compliance, the additional performance benefits usually justify the higher initial cost. For basic domestic heating pipework in a heated space, Tubolit offers a cost-effective alternative where these properties are not required.

Frequently Asked Questions

Is Armaflex better than Tubolit?

For commercial applications, chilled water and any application requiring condensation control or Class O fire rating, yes — Armaflex EVO is significantly better. For basic domestic frost protection on heating pipes, Tubolit is a lower-cost alternative that performs adequately.

Can Tubolit be used on chilled water pipes?

No. Tubolit is an open-cell foam with no vapour barrier. It will not prevent condensation on chilled water or refrigeration pipework. Armaflex EVO must be used for condensation-critical applications.

Is Armaflex worth the extra cost over Tubolit?

For commercial applications, yes — Armaflex EVO provides Class O fire rating, condensation control and Microban protection that Tubolit cannot match. For basic domestic heating pipework in heated spaces, Tubolit is a cost-effective alternative where these properties are not required.

Are Armaflex and Tubolit made by the same company?

Yes. Both Armaflex EVO and Tubolit are manufactured by Armacell. They are different product lines designed for different applications — Armaflex EVO for commercial HVAC and Tubolit for basic domestic use.

Conclusion

Armaflex EVO and Tubolit are both Armacell products, but they are designed for fundamentally different applications. Armaflex EVO is the commercial-grade specification — closed-cell, Class O fire-rated, with a built-in vapour barrier and Microban protection. Tubolit is a domestic-grade product suitable for basic frost protection and heat loss reduction on heating pipework where condensation control and Class O fire rating are not required.

For any commercial, HVAC or condensation-critical application, specify Armaflex EVO. For basic domestic heating pipework, Tubolit offers a lower-cost alternative. Browse the full Armaflex EVO range or use our size guides below.