N.A.T.E. (North American Technical Excellence) - HVAC Exam

We Are An Authroized Testing Organization

LE Hughes and Associate: Is an authorizes "Testing Organization Administrator." Our Proctors are excited to help you as a HVAC&R server provider ; and help the "Technicians" earn your readily accepted  national credentialing.

Contact our office staff 'via' email at either:




or calling

276-202-1447 (cell)

or calling


EXTOL Corporation, Inc

dba LE Hughes and Associates

Are Your Employee Nationally Certified

Contact us soon - to grow your business by enhancing your company image  and professional service certification.

Let our staff help you - to grow your business -  by enhancing your company image  and professional service - build your company reputation  by employing EXPERIENCED highly trained and CERTIFIED service techs.

If you need special tutoring, consulting or training, we are here for you. 

Entry Level HVAC&R Exams for Your New Employees

We can offer your newly employed technicians national entry level credential examination. New employees may like experience, but your can evaluate them and let your customers KNOW; you want to provide "top" service for their TRUST in your company. LET ALL YOUR CLIENTS KNOW YOU HAVE THEIR INTERST AS PARMOUNT --- YOU HIRE  ONLY HIGHLY SKILLED WORKERS. 

ESCO Group Provides National Recoginized HVACR Certification

ESCO Group is partnering with "LE Hughes and Associates" (Div. EXTOL, Inc.) to provide nationally recognized certification through technical competency examination for the Heating, Ventilation, Air Conditioning and Refrigeration "HVACR" industry... LE Hughes (authorized Proctor since 1994) and others "proctors" for ESCO Inritute is the industry’s largest provider of EPA Section 608 certification testing.

    LE Hughes' Authorized Proctors and Associate Trainers are honored and proud to be entering in a venture with ESCO as a key partner by helping the ESCO Institute to continue enhancing its mission; and expanding its services (20+ years) for the Heating, Ventilation, Air Conditioning and Refrigerating Industry, which, includes the development and publishing of training manuals, curriculum packages, assessment exams, specialty training packages and custom publishing solutions for the HVACR and building science fields. 

All visitor to this webpage are encouraged to visits "LE Hughes On-Line Bookstore" to examine the diverse technical offering of texts, study guides and proctored certification exams offered. If your company or technicians need technical reference literature; or to take a proctored certifying exam, place you on-line order with our staff and call or email to schedule an exam date.

276-889-1611 or 276-202-1447  or email: extcorpinc@gmail.com  

It's the law! EPA Refrigerant Recover

Under the Federal Clean Air Act - the EPA requires persons who maintain, service, repair or dispose of appliances that contain regulated refrigerants; must be certified in proper refrigerant handling techniques. 

LE Hughes and Associates operating as authorized proctors and trainers for ESCO, can assist the HVACR industries with this required training for the largest and most recognized mandated certification; by offering training program and can simplify your task by offering our proctored exams, tutoring, specialized training.  

Exams Available: 

(In English and Spanish; either on-line or by hard paper copy versions)
EPA Section 608 for HVACR:  EPA Section 609 for Motor Vehicles   

 Visit our On-Line Bookstore for detailed description; for ordering and for scheduling examination dates.

Call 276-889-1611 or 276-202-1447

email: extolcorpinc@gmail.com 

Progressive Levels of Certification ...With Stackable Credentials Available Thru LE Hughes


Employment Ready Certifications:

Discipline specific exams that show, if a person has the retained knowledge necessary for employment in the HVACR industry. 


Specialty Certifications:

Addressing industry concerns pertaining to: safety, warranty issues, and maximizing energy efficiency. 


Exams Available:
Duct and Envelope Testing: Green Awareness; Hydrocarbon; Refrigerants R-410A; Residential Energy Auditor; Residential Heat Load Analyst;

System Performance