Mills Brothers Heating and Air Offers Charleston HVAC Solutions
Mills Brothers Heating & Air Mills Brothers Heating & Air

HVAC Solutions

When you choose a HVAC company to maintain, upgrade, or replace the heating and air-conditioning systems in your home, you want to hire an experienced company with the knowledge to recommend the best system. Mills Brothers Heating and Air is a locally owned HVAC company with both the experience and knowledge you seek.

Service and Repair

At Mills Brothers Heating and Air, we meet your HVAC needs with highly trained technicians who are NATE and EPA certified. Our senior technicians are all accredited with certifications and trained for diagnosing indoor air quality. Additional certification includes residential and commercial heat load calculations, BPI Certification, and home energy audits. Our staff works together to assure that you will be satisfied with our performance when we come to your home or business.

We have service technicians dedicated to service calls and repairs. Our service calls are usually completed the same day.


By performing precautionary maintenance with Mills Brothers Heating and Air, you can maximize the life of your HVAC system. With regular maintenance you will prevent small problems from becoming big problems and ensure optimal performance of your comfort system.

Regular maintenance will:


Mills Brothers Heating and Air is a local company with a solid reputation for installing new and replacement residential and commercial HVAC systems. We will even work with your builder or contractor and install an ideal system in your newly-built home.


We provide a full range of services to commercial clients. From maintenance and repairs to new installations, let one of our trained technicians maintain your HVAC equipment and help to maintain a productive work environment.

New Construction

In the design stage, we can help you plan the most efficient and cost-effective system for your needs.

How Air Conditioning Works

Think of an air conditioner as a machine that takes heat from your house and sends it outside by using five interrelated parts:

There are many types of air conditioning systems that can be used in the home including window, portable, ductless and central air conditioning systems. However, they all use the following components and direct expansion refrigeration.

Refrigerant: The refrigerant is the "blood" pumping through the air conditioner's system. It changes state from gas vapor to liquid as it collects heat from your house and rejects that heat to the outside. Refrigerant is special in that it has a very low boiling point meaning that it changes from a liquid to a vapor at low temperatures.

Compressor: Think of the compressor as a sort of "heart" of the system pumping the refrigerant though all the refrigeration components in a big loop. Refrigerant enters the compressor as a low pressure warm vapor and leaves it as a high pressure hot vapor.

Condenser: From the compressor, hot refrigerant vapor moves to the condenser. Here the high pressure hot refrigerant vapor is cooled by air blowing over finned condensing coils by the condenser fan as it moves through the finned coils. As the refrigerant cools it changes state from a hot vapor to a hot liquid at high pressure and moves onto the expansion valve. The compressor, condenser coil and condenser fan are all located in the condensing unit, usually in your backyard.

Expansion Valve: The expansion valve is really what does the work. As the hot liquid refrigerant passes through a tiny opening at high pressure in the valve on one side, it emerges as a cool low pressure mist on the other side because as a gas expands, it cools. So now we have a low pressure cold liquid mist that moves onto the evaporator coil.

Evaporator Coil: The low pressure cold liquid leaving the expansion valve now runs through the evaporator coil located in your furnace. Here the hot air of your home blows across the evaporator coil and heats it up while the cold coil cools off the air blowing across it and back into your home. As the refrigerant heats up, it boils and changes from a cold liquid and evaporates into a warm vapor. From there it moves back onto the compressor and exterior condensing unit and the cooling cycles continues.

Client Testimonials

Our Passion for Quality. We are driven to do quality work at a competitive price from start to finish so our final product is something you want to share with family and friends.

Experience + Knowledge. Our experience and expertise allow us to provide the skills needed to customize each system to meet your specific needs.

Our Green Principles. We are proud to offer products and services with "green" principles. Products that offer the ultimate in comfort and health and are environmentally sound.