UL-Certified IE3/IE4 High-Efficiency Motors

UL-certified IE3/IE4 high-efficiency motors comply with the latest US NEMA requirements, saving energy and reducing carbon emissions. UL is a third-party certification body recognized by the US Department of Energy (DOE); once a motor is tested and reported by a UL laboratory, it qualifies for sale as a high-efficiency motor in North America. Verification requires the average efficiency to meet or exceed the nominal efficiency, conducted in a UL efficiency-assessment laboratory per UL 1004-1. Because Kuo Shuay operates its own UL laboratory, we can precisely test and fine-tune the required voltage and frequency. Standard high-efficiency motors use a wide-frequency, wide-voltage design, usable at 50Hz and 60Hz across 200V-480V.

UL Premium IE3 / Super Premium IE4 Motors

Kuo Shuay's UL high-efficiency motors meet IE3/IE4 efficiency. Under IEC 60034-30-1, three-phase induction motor efficiency is classified as IE1, IE2, IE3 and IE4. Compared with IE1, IE4 motors offer higher efficiency, upgraded materials, longer life and greater energy savings.

<Further reading> Table of nominal motor efficiencies

What is a UL-certified high-efficiency motor, and why does it matter?

UL certification means a motor has passed the efficiency assessment conducted by UL - a third-party body recognized by the US DOE - under UL 1004-1, a prerequisite for selling high-efficiency motors in North America. For export-oriented manufacturers, holding UL certification with an in-house UL laboratory means efficiency can be precisely tested and fine-tuned during development, greatly shortening the certification cycle and cutting the time and cost of repeated submissions.

Case study: saving major electricity costs by upgrading to IE4

Customer F is a US cooling-fan company whose products are installed in factories for ventilation. Because these fans run long hours daily, we recommended upgrading the motors to high-efficiency (IE4) class; the efficiency gain adds value to the machine and saves energy costs for end users. In this case they installed ten 11kW motors. The factory owner wanted to know how much could be saved by switching from conventional to IE4 motors - here is the actual calculation.

High-efficiency motor - energy-saving calculation

Ten motors rated 11kW, 4P, 220V, 60Hz, running 12 hours a day, 365 days a year, over five years, at NT$5 per kWh (IE1 efficiency 88.5%, IE4 efficiency 92.4%).

Formula: 11(kW) x (100/88.5 - 100/92.4) x 10(units) x (12h x 365d x 5y) x 5(NT$/kWh) ≈ NT$575,000

Replacing the original IE1 motors with IE4 saves over NT$570,000 in electricity across five years.

General formula: Output(kW) x [100/Eff(IE1) - 100/Eff(IE4)] x units x hours x tariff = money saved.

This case is calculated from IE1 to IE4. Most new equipment today already starts at IE3, so an IE3-to-IE4 upgrade yields a smaller gain, though it remains worthwhile for long-running applications. For the latest mandatory classes by country and IE3-to-IE4 calculations, see the regulation article in Further Reading.

Why choose Kuo Shuay motors

Kuo Shuay operates a UL-certified high-efficiency laboratory and has over 35 years in the industry, able to precisely test and fine-tune efficiency during development and greatly shorten the certification cycle. End customers for our high-efficiency motors include Taiwan's largest semiconductor company and well-known enterprises in Korea and Japan, with proven stability and quality, backed by full technical and after-sales support.

<Further reading> 2026 Motor Efficiency Regulations: IE3 & IE4 Mandatory Timelines and Selection Guide
<Further reading> What are IE3 and IE4 motors? Motor power and efficiency explained
<Products> Kuo Shuay IE4 High-Efficiency Motors | IE3 Standard Cast Iron Motors