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Commercial HVAC Services in Calvert County, MD

Ralph P. Sita, Inc. is a locally owned and operated, full-service commercial HVAC contractor with over 42 years of experience in the industry. Our expert technicians specialize in commercial AC installation & replacement, heat pump installation & replacement, HVAC maintenance & repair, furnaces (Electric/Gas/Oil), boilers (Steam, Gas, & Oil), indoor air quality solutions, ductwork design & installation, unit heaters, air handler units, fan coil units, packaged rooftop units, cooling towers, and system piping,.

Contact us today for a free estimate.

District of Columbia Water & Sewer Authority Advanced Wastewater Treatment Plant​ (Blue Plains)

Our Commercial HVAC Services

AC Installation & Replacement

Heat Pump Installation & Replacement

HVAC Maintenance & Repairs

Furnace Services (Electric, Gas, Oil)

Boiler Services (Steam, Gas, Oil)

Indoor Air Quality Solutions

Ductwork Design & Installation

Unit Heaters

Air Handler Units

Fan Coil Units

Packaged Rooftop Units

Cooling Towers

System Piping

Why Ralph P. Sita Inc. for your Commercial HVAC Needs?

As a leading commercial HVAC contractor serving the DC, Maryland, and Virginia (DMV) area, Ralph P. Sita, Inc. offers a comprehensive range of services to keep your business comfortable and running efficiently. From new installations and replacements to maintenance, repairs, and upgrades, our skilled technicians have the expertise to handle all your commercial HVAC needs.

We've successfully completed projects for a wide range of clients across the DMV area, such as the District of Columbia Water & Sewer Authority Advanced Wastewater Treatment Plant (Blue Plains), WAWA #591 in Prince Frederick, MD, La Plata Plaza in La Plata, MD, Collington Plaza in Bowie, MD, Mike's Auto Body in Owings, MD, ATI Physical Therapy in Bowie, MD, and Tanger Outlets in National Harbor, MD.

Our projects showcase our versatility and expertise, from remodeling the HVAC system for a convenience store to replacing packaged rooftop units, installing new ductwork systems for heat pump split systems, and providing complete HVAC solutions for tenant build-outs and retail stores. When you choose Ralph P. Sita, Inc. for your commercial HVAC needs, you can trust that you're working with a team of experienced professionals dedicated to delivering top-quality workmanship, exceptional customer service, and energy-efficient solutions tailored to your specific requirements.

Looking for a Commercial HVAC Contractor in your Area? We offer Commercial Air Conditioning, Ventilation and Heating Services to the Following Areas:

Calvert County, MD

Anne Arundel County, MD

Prince George's County, MD

Charles County, MD

St Mary's County, MD

Queen Anne's County

Howard County, MD

Montgomery County, MD

Washington, D.C.

Arlington, VA

Alexandria, VA

Fairfax, VA

About Us

As a union contractor with personnel trained and supplied by the Steamfitters Local Union #602, our mechanics have years of experience and are equipped with the most up-to-date training and tools of the trade.


We design, install, and service pneumatic controls, mechanical equipment, heating, air conditioning, and ventilation systems, and offer full-service, commercial and residential, preventative maintenance service contracts.


Ralph P. Sita, Inc. is fully licensed and insured in Maryland, Virginia, and the District of Columbia, and is an accredited business with the Better Business Bureau (BBB).

We work to service, install and maintain all makes of equipment

Commercial HVAC Brands we WorK With

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  • How often should my HVAC be serviced?
    Have your system inspected by a professional HVAC contractor in the spring and fall to coincide with the cooling and heating seasons. This will ensure everything from the blower (the internal motor) to the thermostat is running smoothly and your house will stay warm and cool when you want it to.
  • How often should HVAC filters be replaced?
    Change your filter every three months (each season) for 1-inch filters, or more frequently if you have pets, smoke or allergens in the house, all of which make filters work harder. Each house or unit has a different filter size (some have more than one filter), so check the filter size(s) before you purchase. Energy Star reports that changing the filter is a top DIY action item for a properly functioning HVAC system, as “a dirty filter can increase energy costs and damage your equipment, leading to early failure.”** And just think, each time you replace the filter you are helping to improve the air quality in the house.
  • Why should I perform preventive maintenance?
    Heating and cooling systems work incredibly hard to perform their functions for your household. The constant stopping, starting and continual operation can wear down a machine quickly and unexpectedly if the proper care and maintenance is delayed. However, by performing preventive maintenance, or servicing your system regularly, you can maximize the life-cycle of your heating or cooling unit and guard against many unexpected failures. Preventive maintenance inspections performed on a regular basis can uncover leaks, rust, rot, soot, frayed wires and corroded electrical contacts.
  • What equipment requires preventive maintenance?
    At least once a year, we suggest that homeowners schedule a professional tune-up for the central heating and cooling system in their home. Inspections on boiler and furnace systems should include duct work, pipes, dampers, valves, the chimney, registers, radiators, pumps, blowers, fuel lines, the gas meter, oil tank and every part of the actual furnace and boiler. Meanwhile, heat pump and air conditioning unit inspections should also include inspections of the fan, compressor, indoor coils, outdoor coils and refrigerant lines.
  • Which HVAC system is right for me?
    Schedule an appointment with us. We’ll come to your home and evaluate its size, heating and cooling needs, environment, and the work we’ll need to do. Then, we can recommend the best system for you and install it quickly.
Contact Us Today a free estimate* or Ask Us a question 

Ralph P. Sita, Inc. is a local family-owned and operated, full-service commercial HVAC contractor with over 42 years of experience in the industry. We look forward supporting the needs of your home. Contact us with your information and we'll be in touch.

*Free estimates are for new installations/changeouts only

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