COCOON THRMS-1-3800 Thermal Mass Duct Heater

The COCOON THRMS-1-3800 Thermal Mass Duct Heater is engineered to deliver premium-capacity supplemental heating that helps stabilize indoor temperature swings while maximizing comfort in large residential, commercial, industrial, and specialized HVAC applications.

Unlike conventional electric duct heaters that cycle between full heat and no heat, COCOON Thermal Mass Technology stores thermal energy and releases it gradually. This provides a smoother, more consistent flow of heated air, reducing temperature fluctuations, improving HVAC system performance, and enhancing occupant comfort throughout the conditioned space.

The THRMS-1-3800 is designed for the most demanding heating applications where exceptional supplemental heating capacity, advanced zoning support, and optimized airflow balancing are required without the expense of a complete HVAC system redesign. Ideal for large facilities, high-load environments, and mission-critical comfort applications, it integrates seamlessly into existing duct systems while delivering dependable, long-lasting performance.

Key Benefits

• Helps stabilize indoor temperature swings by smoothing heat delivery in the air stream
• Provides supplemental heating support for larger or uneven HVAC zones
• Reduces hot and cold fluctuations in delivered air for more consistent comfort
• Uses Thermal Mass Technology to store and release heat more consistently than standard electric duct heaters
• Improves overall comfort by supporting existing HVAC system performance rather than replacing it
• Designed for flexible installation in vertical, horizontal, or downflow configurations
• Integrates into existing ductwork with minimal system modification
• Compatible with grid power, solar, backup generators, and hybrid energy systems
• No venting required
• Suitable for residential, commercial, and specialty HVAC applications
• Engineered and manufactured in the United States

General Specifications

THRMS-1-3800-R-P12

Energy Source: Electric Grid, Solar, Wind, Hydro, Backup Generator, or Hybrid Energy Systems

Venting Required: None

Emissions: None

BTU Capacity: 122,148 BTUs

Active BTU: 73,702.27 BTUs

Stored BTU: 48,445.73 BTUs

Active KW: 21.6

Number of Circuits: 3

Number of Circuit Breakers: 3

Voltage: 208-240V / 480V

Hertz: 50 / 60

Full Load Amps: 30 each

Maximum Overcurrent Protection: 45 amps each

Minimum Circuit Ampacity: Per NEC and local codes

Circuit Ampacity: 58 Amps

Recommended Breaker: 60 Amps

Installation Orientation: Vertical, Horizontal, Downflow

Electrical Phase: Single Phase standard (Three Phase available, contact for availability)

Unit Dimensions: 18 x 24 x 54 in

Product Weight: 225 lbs

Shipping Weight: 245 lbs

Safety Listing: UL Listed File Number SA44706

Warranty Information

• 1-Year, 5-Year, and 10-Year Limited Warranty Options
• 10-Year Heat Exchanger Warranty
• See Warranty Documentation for Complete Details

Shipping Information

Shipping Method:
LTL Freight (Where Available)

Shipping Weight:
245 lbs

Country of Origin:
United States

Application Assistance

If you have questions regarding sizing, electrical requirements, installation configuration, or application suitability, our team is available to help determine the best COCOON solution for your project. Call us at +1 314-931-1004