About Us

For the past 60 years, the experts at A-1 Certified Service have given our customers comfort and peace of mind.

We began in the late 1960’s when cooling your home was in its infancy. Tom Thomas opened his doors to provide comfort to the homeowners in Central Florida. In the early 1990’s, Tom moved to Knoxville, TN , and we have been serving the Knoxville and surrounding communities for over 20 years.

In 2012, Tom released the reigns of A-1 Certified Service, Inc. to his daughter, Michele Thomas. Michele is continuing the legacy of providing the highest quality in air conditioning, heating, and plumbing and to ensure each customer receives the comfort they deserve.

Today, A-1 Certified Service, Inc. is driven to provide you the best in class in Air Conditioning, Heating, Air Distribution, Insulation, Home Performance (The philosophy and science based on the premise that homes should be safe, healthy, comfortable, durable, and efficient), and Full-Service Plumbing. A-1 Certified Service, Inc. understands that your home or business’ comfort and energy efficiency is connected and should be treated as an interconnecting system where all aspects affect each other.

Our Commitment To Our Community

A-1 Certified Service, Inc. is committed to serving our community. We support our community through donations and volunteering to our local schools, charities, and Habitat For Humanity. We are proud partners with Knoxville's Community Action Committee (CAC), Knoxville’s KEEM (Knoxville Extreme Energy Makeover) and the Oak Ridge’s MOREE (Make Oak Ridge Energy Efficient) programs.

Our Service Offerings

Residential & Commercial Replacement and Installation

Replacing your home or business' heating and cooling system is an investment in your comfort. We have partnered with Daikin, the world leader in heating and air conditioning, to provide you with the most durable and technologically advanced system. Daikin is the only air conditioning and heating manufacturer to offer 6 to 12-years equipment replacement and 12-years parts warranty. Daikin is the only brand to offer a best in class 12-year extended labor warranty. Let the experts at A-1 Certified Service, Inc. provide the education and support you need to make the best choice for you and your home or business.

Air Conditioning and Heating Repair Residential & Commercial

Let the service experts at A-1 Certified Service, Inc. provide you with accurate repairs to your air conditioning and heating system. Our service experts are NATE certified and maintain their skills through continuous education to provide the highest quality service available.

Residential & Commercial Plumbing

When you have plumbing problems, we are here to support your needs. We provide Full-Service Plumbing for commercial and residential plumbing, including repair and replacement.

Home Performance Air Sealing

Air sealing is the first priority when considering any Home Performance enhancements. Air sealing means that your home’s thermal envelope will be tightened. It can be easily achieved by sealing locations where air and energy leak from your home. Most energy loss occurs in attics, walls, and crawlspaces. Air sealing can seal all penetrations in unconditioned and conditioned spaces if required. It is the most important step to take to reduce utility costs and increase comfort. Air sealing should always be done before any other energy improvement.

Home Performance Duct Sealing

Duct sealing is another important step when improving Home Performance. This is typically the second measure a homeowner should take after air sealing. Duct sealing is important because leaking existing duct systems will remove cooled or heated air from the HVAC system and release it into the attic, crawlspace or between the floors in the home. Traditional duct systems are generally the second largest reason for comfort loss and higher utility consumption in the home. Homeowners can increase their Home Performance by making sure ducts are properly sealed. Duct sealing is achieved by sealing seams on the trunk line, supply, return and ensuring a proper airtight seal is created. Combined with air sealing, duct sealing can achieve higher comfort and greater reductions in utility consumption.

Home Performance Insulation

Proper insulation is vital to increasing Home Performance. Insulation is truly achieved when air sealing and duct sealing are performed. Air sealing, duct sealing and properly insulating the home are the trinity of increasing the home’s comfort and reducing its carbon footprint. Various types of insulation application include batts, blown, and spray foam. Insulating attics, crawlspaces and walls are absolutely essential to increase the home’s energy efficiency potential.

Incorporating air sealing, duct sealing, and proper insulation is the foundation for maximizing Home Performance.

Our Staff

Michelle Thomas
Michele Thomas

Bob Plumadore
Bob Plumadore
Operations Manager

Scott Holt
Scott Holt
Master Licensed Plumber

Client Testimonials

They are a great company! The services we are getting have been outstanding. They are a great bunch of men who work great together. Very prompt and we are very pleased with the difference we are already seeing.

~ BBB Bob A - BBB Bob A

This is the second time your crew has been to my home for A-1.  Again he represented the company with his courteous attitude, professional approach and quality work.  His crew did an excellent job of supporting the job.  Thanks again for the great job.


David B

~ David B - Insulation Review

This is a excellent company. The installed my new Daikin heat/air system. They were very professional and timely. Thank you. You can count on this company to provide the service to your home.

~ FB Mr Bailey - Mr Bailey

More Testimonials