What factors should be considered when selecting an HVAC gasket?

Choosing the wrong HVAC gasket leads to air leaks, energy waste, and system failure. Many of my clients come to me only after such issues have already occurred.

When selecting an HVAC gasket, you should consider temperature range, chemical exposure, compression set, weather resistance, certifications, material compatibility, and cost-performance balance.

I’ll walk you through each of these factors, backed by real application experience and comparison tables to help you make the right decision.

Why does temperature range matter for HVAC gaskets?

If a gasket becomes brittle or deforms under heat, it will fail. That’s why matching the material to temperature conditions is key.

Temperature resistance determines whether the gasket can maintain elasticity and sealing properties during extreme heating or cooling.

Common HVAC Gasket Materials by Temperature Range:

Material	Temp Range	Typical Application
EPDM	-40°C to +120°C	Rooftop units, outdoor ducting
NBR	-30°C to +100°C	Oil-exposed compressor gaskets
Silicone1	-60°C to +200°C	High-temp systems, medical HVAC
FKM (Viton)2	-20°C to +250°C	Industrial exhaust, aggressive chemicals

✅ Tip: For high-heat rooftop HVAC³ or sterilization systems, I always recommend FDA-grade silicone or FKM gaskets.

How does chemical exposure affect gasket performance?

A gasket might survive the temperature—but if it swells, cracks, or dissolves when in contact with refrigerants or oils, the seal fails.

Chemical resistance ensures long-lasting performance in contact with refrigerants, lubricants, cleaners, or industrial chemicals.

Chemical Compatibility Table⁴:

Material	Resistant To	Not Ideal For
EPDM5	Water, steam, mild cleaners	Petroleum-based oils or fuels
NBR	Oils, refrigerants, fuels	Strong acids or ozone
Silicone	Mild chemicals, food-grade environments	Solvents, concentrated acids
FKM	Solvents, fuels, aggressive chemicals	Not recommended for steam

✅ Tip: Use FKM gaskets⁶ for HVAC equipment installed in chemical plants or processing facilities with solvent-rich environments.

What is compression set, and why does it matter?

Gaskets lose sealing function when they permanently deform over time. That’s known as a high compression set.

A gasket with a low compression set maintains its original shape under constant pressure, ensuring a reliable long-term seal.

Compression Set Comparison:

Material	Compression Retention7	Application Insight
EPDM	Good	Suitable for duct flanges and static joints
Silicone	Excellent	Ideal for soft-closing doors8, medical HVAC
NBR	Moderate	OK for moderate cycles in compressor systems
FKM	Excellent	Best for rotating or pulsating components9

✅ Tip: For gasket designs involving door closures or panel access that are frequently opened, low compression set materials like silicone or FKM perform best.

How do certifications influence gasket selection?

If you're supplying public facilities, hospitals, or transportation systems, using uncertified materials could lead to failed audits—or worse.

Certifications like UL94, EN45545, FDA, RoHS, and REACH ensure HVAC gaskets meet fire, chemical, and environmental safety standards.

Certification Summary Table:

Certification	Applies To	Required For
UL94 V-0/HB10	Flame retardancy	HVAC in electronics, transport
EN4554511	Fire safety in rail transport	Train HVAC units
FDA12	Food and medical grade	Hospitals, labs, food processing
RoHS / REACH	Chemical & environmental safety compliance	EU market compliance

✅ Tip: We once helped a Dutch customer pass a fire safety inspection by switching from standard NBR to UL94-certified EPDM. It was the difference between rejection and approval.

Does cost-performance ratio affect your decision?

High-performance gaskets often come at a price—but not every project needs top-tier material. It’s all about matching function with budget.

A good cost-performance balance ensures durability and compliance without over-specifying the solution.

Material Cost-Effectiveness Matrix:

Material	Cost Level	Strength	Weakness
EPDM13	★★★☆☆	Affordable, weather-resistant	Poor oil resistance
NBR14	★★★★★	Low-cost, oil resistant	Not UV/weather resistant
Silicone	★★☆☆☆	High-temp, flexible	Higher cost
FKM	★☆☆☆☆	Extreme durability, chemical-proof	Expensive for general use

✅ Tip: For large commercial HVAC systems where price matters, we often supply NBR gaskets for internal use and EPDM for external duct sealing.

What environmental conditions must be evaluated?

Weather, UV, and ozone exposure can degrade unprotected materials quickly—especially in rooftop or outdoor systems.

Choose materials like EPDM or Silicone that resist weather, ozone, and UV for long-term outdoor performance.

Outdoor Suitability:

Material	UV/Ozone Resistance15	Best Used For
EPDM	Excellent	Rooftop ducts, flanges, outdoor units
Silicone	Excellent	Exposed AHUs, ventilation grilles
NBR	Poor	Indoors only
FKM	Excellent	Industrial systems with sun exposure

✅ Tip: In my experience, using NBR outdoors is a common failure point—cracking appears in just one summer.

Summary Table: HVAC Gasket Selection Factors

Factor	Why It Matters	Best Material Choices
Temperature Resistance16	Prevents cracking or softening	Silicone, FKM
Chemical Compatibility17	Prevents swelling or deterioration	NBR, FKM
Compression Set	Ensures long-term sealing performance	Silicone, FKM
Certifications	Ensures safety and compliance	UL94, EN45545, FDA, RoHS
Cost-Performance	Balances performance with budget	EPDM, NBR
Weather & UV Resistance18	Extends lifespan in outdoor environments	EPDM, Silicone, FKM

Conclusion

Selecting an HVAC gasket isn’t just about price or size. You must evaluate temperature resistance, chemical compatibility, compression set, certifications, weather durability, and cost-efficiency for a lasting seal.

Need help selecting the right HVAC gasket for your project?
Contact Julong Rubber or Request a Quote for expert material recommendations.

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