Insulation for Refrigeration Systems: Materials & Best Practices
Insulation plays a critical role in the performance of refrigeration systems. Whether used in industrial refrigeration systems like chillers, cold storage facilities, or commercial HVAC setups, insulation helps prevent unwanted heat gain that would otherwise force refrigeration units to work harder. This not only affects energy consumption but can also compromise the temperature stability required for safe storage and efficient processing.
Beyond energy efficiency, insulation is key to minimizing the risk of condensation and corrosion under insulation (CUI). Moisture buildup around unprotected or poorly insulated components can lead to significant damage, particularly in systems that operate below ambient temperatures. By maintaining a dry, controlled environment around piping and equipment, insulation helps preserve the mechanical integrity of the system and extends its operational lifespan.
Proper insulation isn't just about selecting the right materials—it's also about correct installation, consistent maintenance, and understanding how to adapt insulation strategies to specific system conditions. In this article, you'll find a detailed overview of how insulation works in refrigeration systems, how to choose suitable materials, and how to prevent common issues like CUI and performance loss.
Insulation reduces heat gain in refrigeration systems, helping equipment operate efficiently and preventing unnecessary strain on compressors.
Selecting the right insulation material—and installing it correctly—protects against moisture ingress, condensation, and corrosion under insulation (CUI).
Ongoing inspection and timely maintenance ensure the insulation system continues to perform effectively and supports the longevity of refrigerated equipment.
What is refrigeration insulation?
Refrigeration insulation is a thermal barrier applied to components such as pipes, compressors, evaporators, and valves within a refrigeration system. Its primary function is to minimize unwanted heat gain from the surrounding environment, helping the system maintain low temperatures with less energy input. Without insulation, refrigeration equipment would need to work harder to compensate for thermal losses, increasing energy consumption and operating costs.
In addition to reducing heat transfer, insulation serves as a critical defence against condensation and ice formation. When humid air contacts cold surfaces, moisture condenses and can freeze, leading to operational issues, corrosion risks, and safety concerns such as slipping hazards. Insulation helps prevent this by keeping surface temperatures above the dew point of the surrounding air.
Effective insulation also reduces the risk of moisture infiltration into the system's components, which can degrade materials over time and lead to corrosion under insulation (CUI). As a result, insulation not only supports energy efficiency but also helps preserve the mechanical integrity and service life of refrigeration systems.
How refrigeration insulation resists heat transfer
Refrigeration insulation works by limiting the three primary modes of heat transfer:
Conduction: This occurs when heat travels through solid materials. Without insulation, heat from the warmer ambient air would transfer directly into colder pipes or components, reducing system efficiency.
Convection: This form of heat transfer involves air movement. Uninsulated surfaces allow air to circulate around them, drawing in heat that can degrade performance or lead to condensation.
Radiation: All objects emit thermal radiation. In refrigeration systems, warm equipment nearby can radiate heat toward cooler components, especially in confined mechanical rooms or plant spaces.
Insulation materials are designed to reduce or interrupt these mechanisms. By creating a continuous, sealed thermal barrier, insulation maintains lower surface temperatures, reduces energy demand, and helps the refrigeration system perform consistently across a range of conditions.
Insulation is essential for the efficiency, reliability, and safety of refrigeration systems. Its value goes beyond energy savings—it directly impacts system longevity, performance, and operational integrity.
Limits compressor load: By minimizing external heat gain, insulation reduces the workload on the compressor. This leads to lower energy consumption, reduced operating costs, and less mechanical wear over time.
Prevents ice and condensation: When warm, humid air contacts cold surfaces, condensation can occur and freeze. This not only degrades insulation but also poses slip hazards and can affect product quality in temperature-sensitive environments.
Enhances system stability: Insulation helps maintain consistent internal temperatures by shielding components from fluctuating ambient conditions. This is especially important for facilities that require strict temperature control, such as food processing plants or pharmaceutical storage.
Protects equipment: Proper insulation reduces thermal stress, which can cause premature wear on piping and joints. It also prevents moisture accumulation that can lead to corrosion under insulation (CUI), a common but avoidable cause of equipment failure.
Insulation performance benchmarks
To ensure refrigeration systems operate efficiently, insulation must meet specific performance standards. One of the primary goals is to limit heat gain to approximately 8–10 BTU/hr per square foot of surface area. Achieving this requires a careful balance of material properties and installation quality.
Key performance metrics include:
Thermal conductivity (k-value): The lower the k-value, the better the material resists heat transfer. This is one of the most important indicators of insulation efficiency.
Vapour permeability: Insulation must resist water vapour intrusion, especially in systems operating below ambient temperature. High permeability can lead to moisture accumulation, degradation, and eventual failure.
Temperature tolerance: Materials should be rated for both the system’s coldest operating temperatures and the warmest possible ambient conditions to ensure consistent performance without cracking, shrinking, or degrading.
Vapour barriers and sealed joints: Even the best insulation material is ineffective if vapour barriers are compromised. Proper sealing at joints, terminations, and transitions is essential to prevent air and moisture ingress.
These benchmarks serve as a guide for selecting materials, determining insulation thickness, and evaluating installation success.
Types of insulation materials used for refrigeration
When selecting insulation for refrigeration systems, it's important to compare materials based on their thermal performance, moisture resistance, and physical characteristics. One of the most referenced performance indicators is R-value, a measure of a material’s resistance to heat flow. The higher the R-value, the greater the insulating power, making it a key metric for energy efficiency.
Material
R-value
Moisture resistance
Flexibility
Typical use cases
Elastomeric foam
Moderate
Low
High
Curved/small pipes
Extruded polystyrene
High
Good
Medium
Standard piping
Polyurethane (PU)
Very high
Moderate
Low–Medium
Cold applications
Polyisocyanurate (PIR)
Very high
Moderate
Similar to PU
Cold/hot systems
Cellular glass
Moderate
Excellent
Rigid
High-moisture zones
PU vs PIR: Both use similar raw materials but in different ratios. PIR has better fire performance and thermal stability, while PU remains flexible and cost-effective. Understanding these nuances ensures you choose the right material for each location.
Key factors to consider when selecting refrigeration insulation
Choosing the right insulation for a refrigeration system involves more than picking a material with good thermal resistance. Each application has unique demands based on operating conditions, system layout, and environmental exposure.
Operating temperature: Insulation must be rated for both the lowest operating temperatures and the highest possible ambient exposures. Materials not suited for these extremes may crack, deform, or lose insulating value over time.
Vapour permeability: In low-temperature systems, even minor moisture ingress can lead to condensation and long-term degradation. Low-permeability materials or integrated vapour barriers are essential for preventing corrosion under insulation (CUI).
Mechanical durability: Insulation must withstand physical stress from vibrations, movement, and maintenance work. Rigid materials may crack under pressure, while more flexible options can better tolerate mechanical impact.
Fire safety: Materials should meet relevant fire ratings and building code requirements. Some applications may require low-smoke or flame-retardant formulations, particularly in confined spaces or occupied facilities.
Regulatory compliance: Ensure the insulation complies with health, safety, and environmental regulations—this includes VOC limits, chemical composition, and potential off-gassing under extreme conditions.
Cost and lifecycle performance: Consider the total cost of ownership. A cheaper material may require more frequent replacement, while a higher-cost option could deliver superior energy savings and lower long-term maintenance expenses.
Best practices for installing refrigeration insulation
Even high-performance insulation can fail if it's poorly installed. Proper installation ensures long-term effectiveness and protects against heat gain, moisture intrusion, and physical damage.
Surface preparation: Insulation should be applied to clean, dry, and smooth surfaces. Any contaminants or surface irregularities can create gaps, reduce adhesion, and allow moisture ingress.
Correct thickness: Insulation thickness should be calculated based on system operating temperature, ambient conditions, and energy efficiency goals. Undersized insulation will result in higher heat gain and possible condensation.
Sealing joints and terminations: All seams and penetrations should be sealed with compatible vapour barriers and adhesives. Even small gaps can undermine system performance and introduce moisture.
Protective jacketing: Jacketing protects insulation from UV exposure, weather, and physical damage. It’s especially important in outdoor or industrial settings where wear and tear is expected.
Follow standards: Refer to established guidelines like ASTM C1710 (installation practices), ASHRAE refrigeration standards, NAIMA guides, or regional codes. These provide proven frameworks for quality control and safety compliance.
Properly installed insulation doesn’t just work better—it also lasts longer, requires less maintenance, and delivers consistent energy performance across the lifespan of the refrigeration system.
How to avoid corrosion under insulation (CUI)
Corrosion under insulation (CUI) is a common and costly issue in refrigeration systems, particularly those operating in humid or outdoor environments. It occurs when moisture becomes trapped beneath the insulation and remains in prolonged contact with metal surfaces. Contrary to popular belief, the insulation material itself doesn’t cause corrosion—it's the retained moisture that creates the conditions for metal deterioration.
CUI typically develops in the following scenarios:
Damaged vapour barriers or jacketing: If the outer protective layer is punctured or improperly sealed, moisture can enter and accumulate beneath the insulation.
Condensation at freeze–thaw interfaces: Temperature fluctuations can cause condensation on cold surfaces, which becomes trapped inside the insulation layer if not properly sealed.
Air exposure at pipe penetrations: Openings, joints, or improperly insulated fittings can allow warm, moist air to infiltrate the system and condense on colder surfaces.
Over time, this trapped moisture corrodes the underlying metal—especially carbon steel—leading to pitting, cracking, and in severe cases, complete structural failure. Once corrosion begins, it’s often hidden from view and may go undetected until system integrity is significantly compromised.
Areas most vulnerable to insulation failure and moisture intrusion
Certain areas of a refrigeration system are more susceptible to insulation failure and moisture ingress due to their geometry, accessibility, or exposure to mechanical stress:
Welds and flanges: These points often feature irregular shapes or joints that are more difficult to insulate and seal properly.
Valve groups and control columns: Frequent maintenance access increases the likelihood of insulation being disturbed or damaged.
Evaporator coil headers and oil pots: These components often operate at variable temperatures, increasing the potential for condensation and thermal cycling stress.
Jacket ends and insulation terminations: Transitions between sections are common weak points where gaps, compression, or improper sealing can allow air and moisture intrusion.
To reduce the risk of CUI, all high-risk locations should be regularly inspected and maintained. Vapour barriers must be intact, and any sign of wet or degraded insulation should be addressed immediately. Using insulation systems designed for ease of inspection or with built-in moisture resistance can further reduce vulnerability in these critical zones.
5 critical factors for a successful insulation system
A high-performing insulation system relies on more than material choice. These five elements are essential for long-term effectiveness:
Proper pipe preparation: Surfaces must be clean, dry, and smooth before insulation is applied.
System design compatibility: Insulation must align with temperature demands, layout complexity, and exposure conditions.
Effective vapour sealing and jacketing: Vapour barriers must be continuous and intact to prevent moisture ingress.
Consistent maintenance and inspection: Regular checks protect against unnoticed damage or degradation over time.
Following these principles helps avoid premature insulation failure and supports the overall reliability of refrigeration systems.
Cost considerations and long-term energy savings
Although refrigeration insulation represents an upfront investment, it delivers measurable savings over the system’s lifetime. Well-insulated systems operate more efficiently, reducing compressor workload and lowering electricity costs.
Lower operational costs: Quality insulation helps reduce energy consumption by minimizing thermal loss.
Resilience to energy cost fluctuations: As utility rates increase, energy savings from insulation become even more valuable.
Lifecycle cost analysis: Comparing material costs, installation labour, maintenance frequency, and energy savings can help identify the optimal insulation thickness and type for each application.
Investing in high-performance insulation not only improves system efficiency, but it also protects equipment, reduces maintenance expenses, and enhances overall operational stability.
Where to buy refrigeration insulation and parts online
Whether you're upgrading insulation on a refrigeration line or replacing damaged components, having access to reliable parts is essential. From pipe insulation and vapour barriers to refrigeration valves, refrigeration compressors, and refrigeration control parts, sourcing the right materials ensures your system continues running safely and efficiently.
IRPC (Industrial Refrigeration Parts Canada) offers a wide selection of refrigeration components, tools, and accessories—all available for purchase online. Their inventory includes insulation materials suitable for low-temperature and high-moisture environments, along with replacement parts for most major refrigeration systems used in industrial and commercial applications.
Ordering through IRPC is quick and secure, with technical support available to help match the right part to your system’s needs. Whether you're maintaining a cold storage facility, an ammonia chiller, or a commercial freezer, IRPC makes it easier to keep operations on track.
