Tariff monitor · Machinery & Equipment

Heat Exchange and Process Heating: Statutory & Effective Tariff Rates

Statutory HTS duty rates for 26 heat exchange and process heating tariff lines (MFN Free–4.2%), from USITC. Effective rate May 2026: 10.66%; monthly history since 20

The short answer

  • The effective U.S. tariff on heat exchange and process heating was 10.66% in May 2026, down from 13.47% a year earlier — calculated duties actually paid divided by customs value, from USITC data. The statutory MFN rate is Free–4.2% across 26 HTS lines in the 2026 schedule. Mexico is the largest source, holding 15.9% of 2025 imports.

Statutory rates from the schedule

  • Heat exchangers, chillers, dryers, and evaporators — moving heat into and out of a process. This family covers HTS heading 8419: 26 eight-digit rate lines with MFN (column 1, general) rates of Free–4.2% in the 2026 schedule.
  • Chapter 99 flags on individual lines mark Section 301/232 overlay provisions (e.g. 9903.88.01) that apply on top of the MFN column.

What importers actually paid

  • Latest month on record (2026-05): 10.66% effective on $1.2B of imports, versus 13.47% in the same month a year earlier. The monthly archive holds 41 observations from 2023-01 through 2026-05.
  • In 2025, U.S. imports for consumption in this family totaled $9.8B in customs value and paid $1.2B in calculated duties: an effective tariff rate of 12.24%. The effective rate captures Section 301/232 overlays, exclusions, and special-program use that the statutory column cannot.
  • A year earlier the effective rate was 2.79%, so the duty burden rose 9.4 points.
  • Top source countries in 2025: Mexico ($1.6B at 3.25%), Taiwan ($1.2B at 10.97%), China ($1.2B at 43.22%), Canada ($857.0M at 2.16%), South Korea ($752.4M at 5.81%).

Representative rate lines

  • 8419.11.00.00: Instantaneous gas water heaters · MFN Free
  • 8419.12.00.00: Solar water heaters · MFN Free
  • 8419.19.01: Other · MFN Free
  • 8419.20.00: Medical, surgical or laboratory sterilizers · MFN Free
  • 8419.33.10.00: For agricultural products · MFN Free
  • 8419.33.50.00: Other · MFN Free
  • 8419.34.00.00: Other, for agricultural products · MFN Free
  • 8419.35.10.00: For wood · MFN Free

Frequently asked questions

  • What is the U.S. tariff rate on heat exchange and process heating? Importers paid an effective rate of 10.66% in May 2026 (calculated duties ÷ customs value, USITC DataWeb). The statutory MFN rate is Free–4.2%; Section 301/232 overlays and special programs explain the difference.
  • What is the statutory MFN duty rate for heat exchange and process heating? Free–4.2% across the family's 26 eight-digit HTS lines in the 2026 Harmonized Tariff Schedule (headings 8419).
  • Which countries supply the most heat exchange and process heating to the U.S.? Top sources in 2025: Mexico ($1.6B at 3.25%), Taiwan ($1.2B at 10.97%), China ($1.2B at 43.22%). Sourcing is diversified: Mexico holds 15.9% of imports.
  • How much heat exchange and process heating does the U.S. import? $9.8B of customs value in 2025, paying $1.2B in calculated duties — an effective tariff of 12.24%.
  • Is the U.S. a net importer of heat exchange and process heating? Yes — a net importer in 2025: $9.8B imported vs $2.5B exported (exports are 26% of imports).

About this data

  • Reference statistics derived from USITC published data. Not a customs ruling; verify rates with a licensed customs broker before relying on them.

Last reviewed 2026-05-12.