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Residential HVAC Services in Calvert County, MD

Ralph P. Sita, Inc. is a locally owned and operated, full-service residential HVAC contractor with over 42 years of experience in the industry. Our expert technicians specialize in residential AC installation & replacement, heat pump installation & replacement, HVAC maintenance & repair, furnaces (Electric/Gas/Oil), boilers (Steam, Gas, & Oil), indoor air quality solutions, and ductwork design & installation.

Contact us today for a free estimate.

Our Residential 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

Looking for Service in your Area? We offer Residential 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, MD

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).

AC Installation and Replacement


AC Installation & Replacement

When it comes to AC installation, repair, and replacement, the first step is to assess your home's cooling needs and determine the best type of AC system for your space. The most common options include central air conditioners, which distribute cool air through ductwork; ductless mini-split systems, which are ideal for homes without ductwork or for zoned cooling; heat pumps, which provide both cooling and heating; window units, which are self-contained and installed in a window or wall; and portable units, which can be moved from room to room. 

Whether you need a new installation, repair, or replacement, the process involves assessing the issue, providing upfront quotes, and ensuring the work is done safely and efficiently. For installations, we properly size the unit, prepare the area, and connect the components according to local codes and manufacturer guidelines. For repairs, we use diagnostic tools to pinpoint the problem and explain your options. If a replacement is necessary, we'll help you find an energy-efficient unit that fits your needs and budget. Our goal is always to keep you comfortable and ensure your AC is running optimally.

Heat Pump Installation and Replacement


Heat pump Installation & Replacement

Heat pumps are a versatile and energy-efficient choice for heating and cooling homes in the DC, Maryland, and Virginia (DMV) area. They work by transferring heat from one place to another, providing cooling in the summer and heating in the winter. When installing a heat pump, we determine the appropriate size and type for your home, safely remove your old HVAC system if necessary, and follow all local codes and manufacturer guidelines for a reliable installation. Heat pumps are well-suited for the DMV's moderate climate and can offer energy savings compared to traditional HVAC systems, especially when paired with a variable-speed compressor.

If your heat pump needs repair, common issues include insufficient heating or cooling, strange noises, or ice buildup on the outdoor unit. Our technicians use diagnostic tools to identify the problem and provide upfront quotes for repairs. Regular maintenance, such as annual tune-ups, is crucial for preventing issues and extending the life of your heat pump. While heat pumps may have a higher upfront cost than central AC systems, their energy efficiency and ability to provide both heating and cooling can lead to long-term savings. 

HVAC Maintenance and Repair


HVAC Maintenance & Repair

Regular HVAC maintenance and timely repairs are crucial for keeping your heating and cooling system running smoothly and efficiently in the DC, Maryland, and Virginia (DMV) area. Common issues that can affect air conditioners and heat pumps include refrigerant leaks, frozen evaporator coils, compressor failures, and clogged condensate drains. Furnaces and boilers may experience problems with pilot lights or ignition, heat exchanger cracks, thermostat malfunctions, and dirty burners.

To prevent these issues, scheduling annual maintenance tune-ups is essential. During these visits, our technicians thoroughly clean and inspect your system, check for potential problems, and ensure proper operation. If you do experience issues, it's important to call for professional repairs promptly.

Furnace Services


Furnace Services (Electric, gas, Oil) 

We install and service the three main types of furnaces: electric, gas, and oil. Electric furnaces use heating elements to warm the air and are typically less expensive to install but may have higher operating costs. Gas furnaces, the most common type in the DMV area, burn natural gas or propane to heat the air and are generally more energy-efficient and cost-effective. Oil furnaces are less common but still used in some older homes; they burn oil to generate heat and require an on-site storage tank for fuel. They typically require more frequent maintenance than gas or electric models.


We recommend scheduling an annual furnace maintenance before the start of winter. During these visits, we'll thoroughly inspect your system, clean key components like burners and heat exchangers, test safety controls, and make any necessary adjustments to optimize performance. If you experience issues with your furnace, such as uneven heating, strange noises, or poor air quality, it's important to call for professional repairs as soon as possible to prevent further damage and ensure your family's safety. 

Boiler Services


Boiler Services (Steam, gas, Oil) 

Boiler systems are a reliable and efficient heating option for homes in the DC, Maryland, and Virginia (DMV) area. The two main types of residential boilers are hot water boilers and steam boilers. Hot water boilers heat water and circulate it through pipes to radiators, baseboard heaters, or radiant floor systems, providing consistent, even heating. They are more energy-efficient and responsive to thermostat changes compared to steam boilers. Steam boilers heat water until it turns into steam, which then travels through pipes to cast-iron radiators, where it cools and condenses back into water, releasing heat. Steam boilers are typically found in older homes and can be less energy-efficient and require more maintenance. Both boiler types can be fueled by natural gas, propane, or oil, with gas being the most common in the DMV area.

We recommend scheduling annual maintenance to inspect your boiler, test safety controls, clean key components, and flush the system to remove any accumulated sediment or scale. If you experience any issues with your boiler, such as uneven heating, strange noises, or leaks, call us and we can help diagnose the issue, prevent further damage and keep your home warm and comfortable.

Indoor Air Quality Solutions


Indoor Air Quality Solutions

The DC, Maryland, and Virginia (DMV) area, is known for its issues with high humidity levels, dust, pollen, and mold growth. Implementing proper indoor air quality solutions improves the air you breathe inside you home and can promote a healthier, more comfortable living environment. 


We can help improve your indoor air quality through:
- Air Filtration Systems:
- Air Purifiers
- Humidifiers and Dehumidifiers
- Ventilation Systems
- Duct Cleaning

Ductwork Design and Installation


Ductwork Design & Installation

We specialize in creating custom ductwork solutions tailored to your home's unique needs and layout. When designing ductwork for a home we take into account:

  • Load calculations: An analysis of your home's heating and cooling needs based on factors like square footage, insulation, window placement, and occupancy. This information helps determine the appropriate size and capacity of your HVAC equipment and ductwork.

  • Ductwork sizing: Using industry-standard tools like Manual D, we'll calculate the proper size and configuration of your ducts to ensure optimal airflow and pressure balance.

  • Duct layout: We'll design a duct system that efficiently distributes air to each room in your home, taking into account factors like the location of supply and return vents, the length and routing of ducts, and the need for zoning or dampers to control airflow.

  • Material selection: We'll recommend the best material for you home; common options include sheet metal, fiberglass duct board, and flexible ducts.


Once the design is finalized, we oversee the professional installation, including:

  • Fabrication

  • Installation

  • Insulation

  • Testing and balancing

Contact Us Today a free estimate* or Ask Us a question 

Ralph P. Sita, Inc. is a local family-owned and operated, full-service residential 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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