About Air Doctor Heating and Air

The Best HVAC Company in Frederick

Our Mission & Values

At Air Doctor Heating and Air, we believe in providing outstanding service and value. Air Doctor Heating and Air is committed to inspiring you to become our customers for life. 

Our goal is to ensure we are your first choice of all HVAC companies in Frederick.


We stand behind our product and our staff.  We provide the only 10 year parts and labor warranty in the industry.


We are a family-run company.  We treat our employees like family.

Fast & Responsive

We want our customers to know that we will fix their problems quickly without creating more.


We provide the right solution the first time.

Offering the Most Professional HVAC Services In Your Area

Our uniformed and highly skilled team are fully background checked, certified and are ready to serve all your HVAC needs.

Air Doctor Heating and Air is proud to announce our acceptance into the Google Guarantee Program.

This program has been established by Google to help ensure customers that the merchants they are considering have been fully vetted for licensing, insurance compliance, customer ratings and technicians have been background checked so they meet their high Google standards.

Why Air Doctor Ranks Best of all HVAC Companies in Frederick

Air Doctor, LLC dba Air Doctor Heating and Air is licensed, insured and accredited. Servicing the central Maryland area since 2013 with outstanding Five Star complete residential and commercial HVAC Services including Heating, Heat Pumps, Air Conditioning and Air Quality Control Systems.

The Company is owned and operated by Scott and Barbara Karr. Scott Karr has been working with HVAC systems since 1994 and has held his Master HVAC License for over ten years.

Dedicated to providing you with the best products and services possible. Employing only highly qualified and professional technicians and providing them with ongoing training to keep them abreast of all technology advancements.

All our technicians are fully screened and properly tested. You can trust our staff at Air Doctor Heating and Air.  We know there are a lot of HVAC Companies in Frederick, but we strive to be the best with the best service and warranty in town!

HVAC Companies in Frederick

Meet Your Team

Committed to providing you with our Best AIR DOCTOR HEATING AND AIR Installations, Service and Repairs. Our staff looks forward to working with you!  Our team is one of the reasons we are one of the best HVAC Companies in Frederick!

Scott Karr

Founder and Owner

Scott Karr- From Mt. Airy, MD originally and now residing on his farm in Boonsboro, MD. Scott has honed his HVAC skills over the years leading up to when he would realize his dream of providing the best HVAC products and services in the industry. He then founded Air Doctor, LLC dba Air Doctor Heating and Air.

Having raised his three daughters, it was the perfect time to open his business in 2013 with his loving wife Barbara to run the office and support the business. After working at several prominent HVAC companies in the Metropolitan area, Scott realized that he wanted to create his premiere company with the focus on customer service, something that other companies were lacking. Master HVAC, NATE, EPA-CFC licensing.

Barbara Karr


Barbara Karr- Barbara hails from Jamestown, NY and Graduated from Jamestown Senior High School, but has resided in Maryland since 1979. Barbara is a mother of three beautiful daughters and a grandmother of four.

Barbara worked in Sales, Marketing and Customer Service throughout a number of varying industries and enjoys networking across many fields. Advantages which she brings to Air Doctor, LLC dba Air Doctor Heating and Air. Barbara earned Top 10 Sales Nationwide with Miles Homes.

Ken Walters

Ken Walters

Comfort Specialist / Sales

Ken is our Air Doctor Heating and Air Comfort specialist and he is dedicated to providing our residential customers with the very best options for all their heating, air conditioning and indoor air quality needs.

He is pleased to assist our small business customers and churches with qualifying for the Empower Maryland program. With thirty years of experience, he uses his vast knowledge and experience to assist our customers will all their comfort needs.

Office/ Customer Servicce

Kelli Terembula

Office / Customer Service

Kelli has a great deal of experience in seeing that customer’s needs are satisfied. She has extensive skills in handling customer concerns and getting the right staff promptly to meet our customer’s needs.

Being detail oriented, excellent in communications, efficient and very pleasant to speak with, you will find yourself in great hands with Kelli.

Senior Install Technician

Warren Roelkey

Senior Install Technician

Warren is an integral part of our dedicated installation team. With over fifteen years experience and vast knowledge, he gets new systems up and running quickly and efficiently.

His commitment and dedication to ongoing training provided by Air Doctor Heating and Air, he keeps abreast of the newest technologies and systems.

Ken Walters

Tony McDonald

Mechanic / Technician

Tony McDonald- From Martinsburg, WV, T.J. is our indispensable Lead Tech at Air Doctor Heating and Air. Graduating from Jefferson High School, he was SGA President at Valley College, where he graduated top of his class. EPA, 410A, OSHA Certified.

Office/ Customer Servicce

Marcus Wengert

Journeyman / Technician

Marcus Wengert- Marcus was raised in Glen Burnie, MD and found that he had quite a talent for mechanical work. He soon found his niche in the HVAC industry and has over fifteen years as a certified journeyman technician and joined Air Doctor Heating and Air just this year.

Marcus is a great asset to our team! EPA CFA License.


Klismar Ramirez


Klismar is very hard working, talented and is currently studying to become a fully licensed technician. He is experienced with tools, is energetic and learns quickly. He is very adaptable and assists several of our technicians in the field. We are pleased to have him on our team.

Ken Walters

Abraham Ramirez


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