HVAC Service: Everything You Need to Know Before Hiring an HVAC Company

What You Need To Know To Hire A Heating & Air Conditioning Company In Northern VA

When you’re looking to hire a company for HVAC service (Heating, Ventilating, and Air Conditioning) it can feel a little overwhelming, particularly if it’s your first time. You may not know what type of HVAC service you need, what to look for in an HVAC service technician, or how to find an HVAC service company.

Here at AirPlus Heating, Cooling, Plumbing & Electrical, we believe that knowledge is power andeveryone should be armed with the proper information to help them choose the ideal HVAC service company. That’s why we’ve put together this guide with everything you need to know about your HVAC unit, different types of HVAC service, HVAC service cost, and how to choose the right HVAC service company.

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HVAC 101: Learning About Your Unit

Knowing how your HVAC system operates helps when you’re seeking an HVAC service company. The more you know about your unit, the better off you’ll be when something goes awry or you need an expert opinion. This way, you’ll better understand what’s happening when you have a maintenance call — and you’ll more easily be able to spot any issues that might arise with the different parts of the system. 

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The different types of HVAC systems include: 

  • AirPlus is Northern Virginia's Trane Comfort Specialist.

    Heat Pump Systems

    These are all electric systems that are used when a home doesn’t have natural gas, propane or oil. Essentially a heat pump is a highly efficient air conditioner that works all year round. It includes an indoor air handler and an outdoor condenser that circulates refrigerant. In the summer, it uses the refrigerant to cool the air, and in the winter, it provides warmth by reversing the flow and pulling heat out of the outdoor air. When the temperature falls to a certain level, around 35 to 40 degrees, the system may have a hard time keeping up so it will cycle on backup electric heat. This maximizes efficiency as the less efficient electric heat only needs to be used when the outside temperature drops to a certain level. 

    Below is a list of the items contained in a heat pump system; keep reading for the next section where we discuss what each component does.

    • Compressor
    • Condenser
    • Condenser fan motor
    • Reversing valve
    • Defrost control board
    • Evaporator coil
    • Indoor blower motor
    • Heater pack
  • Lennox ML180UH 80% Efficient gas furnace by Airplus Home Services

    Gas Furnace Systems

    A gas furnace system is the most common type of HVAC system. It consists of a furnace (indoors) and an air conditioning condenser/heat pump (outdoors). When the temperature drops, the fuel is ignited via burners that run on gas, oil or propane, then sent through the heat exchanger. The inside of the heat exchanger is heated up and then air is blown around the outside of the heat exchanger. The blower motor sends hot air around the outside of the heat exchanger and throughout the home. The blower motor is also utilized by the air conditioning system to cool the home. 


    A gas furnace system includes: 

    • Inducer motor
    • Igniter
    • Gas valve
    • Flame sensor
    • Heat exchanger
    • Blower motor
    • Burners


  • AirPlus installs and services air conditioners & heat pumps in homes in Fairfax County and throughout Nortehrn Virginia.

    Air Conditioner Systems

    The air conditioner system cools your home via a condenser which contains a coil, a compressor, and a fan motor which is connected via refrigerant lines to an evaporator coil. When the thermostat hits the set temperature, the compressor and both fan motors start up. Refrigerant is pumped from the compressor into the condenser coil. Heat is then blown across the condenser coil and the refrigerant turns from a vapor into a liquid. It’s then pumped to the evaporator coil where it is converted back to a vapor. Then the indoor blower motor (typically from the furnace) blows warm air across the cold evaporator coil and the air is absorbed into the refrigerant circuit. When the heat is absorbed out of the air, the blower then pushes the conditioned, cool air throughout the home.

    An air conditioner system includes:

    • Compressor
    • Condenser coil
    • Condenser fan motor
    • Evaporator coil
    • Indoor blower motor 
  • Lennox 20 Seer HVAC Package

    HVAC Hybrid Systems

    These systems include both a gas furnace and a heat pump. Because utility prices vary based on the time of year with gas prices typically going up in the wintertime versus electric, these systems go back and forth between the two. For most of the year this system will use the more efficient heat pump process as described above. Then when it drops to around 35 or 40 degrees, it kicks over to the gas furnace. Using both optimizes each component and maximizes efficiency. 

    An HVAC Hybrid systems include: 

    • Compressor
    • Condenser
    • Condenser fan motor
    • Reversing valve
    • Defrost control board
    • Evaporator
    • Indoor blower motor
    • Inducer motor
    • Igniter
    • Gas valve
    • Flame sensor
    • Heat exchanger
    • Burners
  • home heating boiler system

    Boiler Systems

    This is a standalone heat-only system that uses fossil fuel, typically oil or gas. It includes a heat exchanger that has water flowing through it. The fuel heats the water and it’s pumped through pipes into radiators or baseboards. Boilers come in different efficiencies from a standard efficiency to a high efficiency gas tankless boiler. 


    Boiler systems include:

    • Heat exchanger 
    • Burners
    • Pump
    • Gas valve
    • Igniter
    • Flame sensor
    • Ignition control module
  • Mitsubishi Ductless M-Series MSZ-FH09NA, MSZ-FH12NA indoor units and MMXZ2C20NAHZ outdoor unit

    Ductless or Mini-Split Systems

    These systems are high efficiency heat pump or air conditioning systems that use a variable speed compressor which is installed outside. As the name implies, there’s no duct work. There are several styles of air handler units that can be installed on individual walls, floors, ceilings or as traditional duct units. The variable speed compressor in a heat pump system will modulate based on thermostat set point and outdoor temperature and doesn’t require electric heat as a backup. The outdoor unit talks to the indoor units and by varying the speed of the compressor outside you can keep your house at a temperature of 70 to 75 degrees. These systems can run heat down to negative 13 degrees and cooling down to zero degrees, and they deliver only what’s needed into any given space.

    Ductless or Mini-Splits systems include: 

    • Compressor
    • Condenser
    • Condenser fan motor
    • Reversing valve
    • Defrost control board
    • Evaporator 
    • Indoor blower motor

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The Most Important Components of Your HVAC System as Listed Above Are:

  • Compressor

    Installed inside the condensing unit outside the home, the compressor is a pump that moves refrigerant throughout the system. Refrigerant gas is the median used to absorb or reject heat. By pumping refrigerant through the system and changing state from liquid to gas we are able to absorb and reject heat.

  • Condensing Unit

    The condensing unit is used to reject heat. It is part of the total system and is connected to the evaporator coil. As the compressor moves liquid refrigerant to the evaporator coil, it is vaporized and absorbs heat. It then moves out to the compressor and is converted from a low pressure vapor to a high pressure vapor where it enters the condenser coil. As it is converted from a vapor in the condenser it rejects heat and is turned back into a liquid to start the cycle all over again. 

  • Evaporator Coil

    The evaporator coil is part of the refrigeration circuit. It’s job is to absorb heat and this happens when the refrigerant liquid entering it is converted to a vapor and hot air is blown across it. It’s then pumped to the compressor and the condenser where its converted back to a liquid and starts the cycle all over again. 

  • Condenser Fan Motor

    The condenser fan motor is used to blow hot air across the condenser coil which releases the heat and is turned back into a liquid.

  • Reversing Valve

    This reverses the refrigerant flow depending on which mode you are in, heating or cooling. 

  • Defrost Control Board

    The defrost control board and its temperature sensors monitor the condenser coil for freezing conditions. When the condenser coil starts to frost up, the defrost temperature sensor will send a signal to the defrost control board letting the system know it needs to go into the defrost cycle.

  • Blower Motor

    The blower motor is contained in the indoor unit and is cycled through the indoor control board. In the heating mode it will blow air across the warm heat exchanger and in the cooling mode it will blow air across the cold evaporator. When the thermostat it is in the fan “on” position the blower motor will just move air around the house without a call for heating or cooling.

  • Heater Pack

    The heater pack serves as a source of backup heat. It’s typically activated if your heat pump falls two degrees or more below set point. 

  • Inducer Motor

    The inducer motor moves exhaust gas from the heat exchanger to the outdoor so dangerous carbon monoxide does not build up. 

  • Ignition Control Module

    In a boiler, gas or oil furnace, the thermostat tells the ignition control module to activate the igniter.

  • Igniter

    The igniter is triggered by the thermostat in the heat mode and it’s what is used to ignite the gas.

  • Gas Valve

    Also triggered by the thermostat in the heat mode, when prompted the gas valve opens to allows gas to flow across the igniters and light and push flame through the burners into the heat exchanger. 

  • Flame Sensor

    The flame sensor insures that raw gas coming from the gas valve ignites so raw gas isn’t being released into your home. If the flame doesn’t ignite, it shuts the system down as a safety measure. 

  • Heat Exchanger

    This component is located inside the furnace and is part of the heating cycle. It contains the burners and the flame and air is moved across the outside of it via the blower motor sending warm air to the distribution system of the home. 

  • Burners

    Burners are the components that burn the fuel to supply heat to the heat exchanger. There are usually several within an HVAC unit.

  • Thermostat

    The thermostat is the way you interact with the HVAC system in your home. It’s mounted on a wall, and through it you program or set your preferred temperature — sometimes from room to room. When the air gets too hot or too cold, the thermostat triggers the system to release cool or warm air.

  • Furnace

    A furnace is a major component of your HVAC system and essentially serves as a cabinet that holds all other components of the heating system. It’s installed inside the house, typically in a basement, cellar, attic or other room. It heats the air that circulates throughout the distribution system using natural gas, oil, or propane. 

  • Filter

    Every unit has a filter which catches dirt and debris and needs to be changed regularly to keep your system clean and running at maximum efficiency.

  • Ducts

    Ducts are the distribution system that move warm or cold air from the HVAC system to the different rooms of your home.

  • Vents

    The vents are attached to the ducts and terminate the air from the ducts directly into different rooms. They’re made of metal or wood, have slats for the air to pass through and in some cases can be opened and closed in order to control air flow.

Typical Types of HVAC Services

Staying current on HVAC service is key for ensuring your unit is in its best working condition and continues to heat and cool your home at maximum efficiency all year round. 

The most common types of residential and commercial HVAC service are maintenance services and emergency services. In order to avoid emergency services or more expensive HVAC service cost, maintenance visits should be scheduled twice a year. 

Dirt and neglect are the top reasons for the failure of HVAC systems, so staying current on maintenance will save you money long-term. 

Maintenance visits also allow your HVAC service company to keep a record of your unit’s performance so they can compare it over time and keep a baseline from year-to-year. Knowing your unit and how it operates will help your HVAC service technician keep it in its best working order long term. 

If you’re wondering what constitutes an annual HVAC service maintenance visit, here’s what you can expect the HVAC technician to do: 

  • Test the calibration and functionality of the thermostat
  • Inspect the indoor and outdoor coils 
  • Check the air filter
  • Inspect the electric heater controls and operation
  • Inspect the relays and indoor unit wiring
  • Check the indoor blower motor
  • Check the overall physical condition and operation of the system
  • Test the rise and fall of the indoor temperature
  • Inspect the outdoor fan blade balance
  • Inspect outdoor fan motor
  • Inspect contactor points
  • Inspect standing components
  • Test the compressor’s amperage and performance
  • Inspect the refrigerant pressure
  • Test the defrost components
  • Test the reversing valve operation

A summer cooling HVAC service visit includes checking and adjusting the following:

  • Install gauges and check operating pressure
  • Check the condenser coil
  • Check and tighten all electrical connections
  • Lubricate bearings and motors as needed
  • Inspect and clear condensate drain
  • Cycle and check thermostat for accuracy
  • Check and adjust fan belt as needed
  • Check voltage and amperage to condensing unit
  • Clean and change air filter as needed
  • Adjust charge to proper sub-cooling or super heat per factory specs

A winter heating HVAC service visit should include checking and testing the following: 

  • Perform combustion analysis
  • Inspect heat exchanger for cracks and soot
  • Check flue pipe for adequate draft
  • Check burner operation
  • Check fuel supply for leaks and operating pressure
  • Check pilot assembly
  • Check fan control and limit operation
  • Cycle and check thermostat for accuracy
  • Clean flame sensor
  • Clean and change air filter as needed

Keep in mind that adding Freon or using a filter supplied by your HVAC service company will likely be an extra charge in addition to the maintenance check.

So how will you know when it’s time to service? Ideally your HVAC service technician will tell you if anything is amiss with your unit. Otherwise, you should schedule your maintenance visit for twice a year.

The rest of the time, be on the lookout for signs like your AC no longer cooling, water leaking during the AC season, a block of ice on the refrigerant line, or anything else that seems inappropriate. All of these are telltale signs that there may be something wrong and you need a service visit.

Mother and daughter sitting in front of fan on a hot day.

Depending on your needs, there are different options for HVAC units made by companies like Lennox, Carrier, Trane, and Mitsubishi just to name a few. 

Unless you’re building a new home or looking to change your HVAC unit, your home likely already has one of the aforementioned systems installed. And if you’re looking for a new unit, it’s always best to take a look at the best brands before making your choice.

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HVAC Service Cost: What Should You Be Paying

The cost of HVAC service can vary depending on a variety of factors. While many companies charge the same price for a maintenance visit whether it’s a heat pump or an AC and furnace, others may have differing rates. Also, emergency visits will vary based on what needs to be repaired. 

Factors that can affect the cost of a visit include:

  • Calling after hours or on weekends, which can lead to overtime pay.
  • Not scheduling maintenance visits, which can lead to emergency services and unexpected repairs.
  • Scheduling service during peak times, such as the middle of summer when most HVAC service companies are booked.

Unexpected costs are more likely when there’s a lack of maintenance, as the unit may have issues that aren’t immediately obvious to the owner. Sometimes components fail because there’s a deeper issue or other repair that hasn’t yet been addressed.

Some common, potential scenarios that can happen when you don’t have regular maintenance include:

  • When the temperatures rise during the summer capacitors tend to fail. They provide the third leg of power, and once a capacitor gets out of tolerance it stops providing the proper voltage. With improper voltage the motor can fail. 
  • AC units create condensate in the evaporator coil that has to be removed via a pipe that drains to a floor drain or outside. Without routine maintenance that drainpipe can get clogged and back up and flood a furnace or a floor and cause water damage.
  • If filters aren’t changed they can get clogged. This restricts air through the evaporator coil and causes the system to work harder than it was designed to. This will eventually lead to the evaporator coil freezing, defrosting, and causing water leaks.
  • The contactor is a high voltage switch that turns the outside compressor on and off. Over time it gets pitted and if it gets pitted too badly it can weld shut and either keep everything running nonstop or not allow anything to turn on. 
  • If a system doesn’t have the proper amount of refrigerant it will run up utility bills but won’t maintain a comfortable temperature. This will also cause the evaporator coil to freeze up, thaw and cause water leaks.
  • When the refrigerant gets really low it can start freezing up the evaporator coil. A block of ice will form and when it starts melting it will cause flooding or other water problems.
  • With a fuel burning appliance in the house, it’s important to make sure it’s working properly so it doesn’t create dangerous carbon monoxide. Without a  yearly combustion analysis the system could be pumping flue gas directly into the home creating dangerous CO (carbon monoxide) levels. 

A single maintenance inspection should run between $69 and $89. This is just an inspection, and doesn’t include cleaning or other services. 

The purpose of the maintenance inspection is to insure the unit is in proper working order. If an HVAC service technician finds an issue, the cost will vary depending on the complexity of the job, the price of the parts and other factors. 

Some maintenance, like filter changes, you can perform yourself. A one inch filter should be checked monthly, while high efficiency media air cleaners can be changed every 6 to 12 months. 

If you need a new system or are looking to make a significant purchase, financing options are also available. 

Finding the Right HVAC Service Company

When looking to hire an HVAC service company, there are a few key qualifications that are important to keep in mind. 

One quality certification to look for is the North American Technician Excellence (NATE) certification. It’s the nation’s largest nonprofit certification organization for HVAC service technicians. NATE-certified technicians are able to acquire four different levels of certification:

  • Ready-to-Work certificate
  • HVAC support technician certificate
  • NATE certification for core and specialty tests
  • Senior level efficiency analyst certification. 

Each level requires more education and experience. 

In addition, consumers should seek to hire Class A, or general engineering HVAC service contractors. Class A contractors are able to perform jobs of all sizes and types, meaning they’ve invested more time and have more extensive experience. General building contractors, or Class B, and specialty contractors, or Class C come with significant restrictions on the work they can perform. It’s better to hire a Class A contractor who’s able to handle any potential issue that might arise. 

As you screen companies to hire an HVAC service technician, you’ll want to do due diligence and make sure you’re hiring the best possible company for your specific needs. Questions to ask your potential HVAC service contractor include: 

  • How long have you been in business?
  • Do you have a physical office?
  • Do you have a full-time administrative staff?
  • Are employees available to answer the phone when you call?
  • How many employees do you have? How big is the company?
  • How many master technicians do you employ? 
  • Do you employ NATE-certified technicians?

Lastly, consumers should look at review sites such as Google, Yelp, and Angie’s List to see what former customers have had to say about an HVAC service company. Reviews are written by fellow consumers who often have a lot of insight and detail about how the company operates and their personal experience. 

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HVAC Service: Choosing the Right Company

Now that you know a little bit more about HVAC service, hopefully you’re equipped to hire an HVAC service company that can meet your specific needs. Be sure to look for a company that has extensive experience with jobs of all kinds, Class A contractors, great reviews, and an established location and staff. 

At AirPlus Heating, Cooling, Plumbing & Electrical, we’re happy to provide you with an HVAC service cost estimate. Fill out the form below or call us to schedule a free estimate!

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