Common HVAC Questions


Your Common HVAC Questions, Answered By HVAC Specialists

  • What does HVAC stand for?

    HVAC stands for Heating, Ventilation, and Air Conditioning.

  • What components make up an HVAC system?

    A heating unit, a cooling unit, and a duct used to distribute warm or cooled air make up a standard HVAC system.

  • What is a SEER?

    The SEER stands for Seasonal Energy Efficiency Rating. The higher the SEER rating of an air conditioner, the more efficiently the system is going to run with lower operating costs.

  • What is a HSPF?

    The HSPF rating stands for Heating Seasonal Performance Factor. It's the heating efficiency of a heat pump. The higher the HSPF rating of a heat pump, the more efficiently the system is going to run with lower operating costs.

  • What is an AFUE?

    The AFUE stands for Average Fuel Utilization Efficiency. It rates the efficiency of oil-fired and gas furnaces. The higher the AFUE rating, the greater the heating efficiency.

  • What does BTU stand for?

    The BTU stands for British Thermal Unit. British thermal units (Btu) are a unit used to measure the amount of heat in fuels or other energy sources.

  • What is an EER?

    The EER stands for Energy Efficiency Ratio. It measures the energy efficiency of an air conditioner or heat pump. The higher the EER rating, the more energy-efficient the air conditioner or heat pump is going to be.

  • What is a CFM stands for?

    The CFM stands Cubic Feet Per Minute:. It's a measurement of airflow volume.

  • What is a BTU/H stands for?

    BTU/H stands for British Thermal Units Per Hour.

  • What is a split system?

    A split is also referred to as a forced-air system; a split system has one unit inside the home and one outside. This configuration can include a furnace and air conditioner, an air handler and heat pump, or a furnace and heat pump.

  • What is a hybrid heat pump?

    A hybrid system is also known as a dual fuel system. This system is a combination of a furnace, a heat pump, and an evaporator coil. During the milder months of the year, such as spring and fall, heat pumps heat your home. If the weather is too cold for the heat pump to work effectively, the furnace takes over. The hybrid system is very cost-effective to run when a heat pump is heating the house rather than a gas furnace.

  • What is a ductless mini-split?

    An electric heating and cooling system is referred to as a ductless air conditioner, ductless mini-split HVAC unit, or ductless mini-split heat pump. A ductless system has one outdoor AC condenser or heat pump and can have one or multiple air handler units connected inside the house to that. An indoor air handler is mounted on the wall, which directly blows air into the room. For a house without ducts, this type of system is very cost-effective to install and can cool or heat each individual area based on the desired temperature.

  • What is a ducted mini-split?

    A ducted mini-split system uses smaller ducts instead of larger ducts to move air into rooms. This solution is best for homes where there isn’t a lot of room for conventional ductwork. Compared to ductless mini-split systems, ducted mini-splits have the advantage of better air circulation.

  • What is a packaged system?

    Packaged units, often referred to as "packaged systems," are self-contained systems that combine the cooling and heating elements into a single unit. Split systems have an indoor and an outdoor unit, whereas packaged units only have an outdoor unit that is normally located outside, either on a flat roof or on a slab of concrete near a building. A packaged unit's air is distributed through ductwork that is run through a wall or the roof.

  • What is a HVAC zoning system?

    An HVAC zoning system, often known as "zoned HVAC," is a heating and cooling system that controls and directs air to particular regions of the house using dampers in the duct.

  • How does a dual-fuel or hybrid system work?

    The dual system and the hybrid system are identical. In this application, a furnace and an electric heat pump are both part of the central heating system. The heat pump heats the house during the milder seasons of the year, such as spring and fall. When the temperature gets too low for a heat pump to work efficiently, the furnace takes over to keep up with the cold weather. They both save money for consumers in the long run because it costs less to heat a home with a heat pump than with a furnace.

  • How often should i service my air conditioner?

    You should have your air conditioning system maintained by an HVAC specialist at least once a year. Similarly, your heating system and heat pump.

  • What's involved in servicing an air conditioner?

    Air conditioner maintenance, or air conditioner tune-up, involves checking the thermostat, air filter, blower motor, blower current amplifier, circuit board, safeties, evaporator coil condition, drain pan, drain line, condenser coil condition, condenser fan motor, condenser contactor, condenser current amplifier, and refrigerant pressures. During the AC maintenance, if any component faults are discovered, the HVAC professional will advise a repair or replacement as necessary.

  • How often should a gas furnace be serviced?

    It is important to service a gas furnace by HVAC specialist at least once a year, ideally twice—in the spring and fall. By having a gas furnace inspected, an unexpected breakdown can be prevented during the cold winter and hot summer.

  • What's involved in servicing a gas furnace?

    Furnace maintenance, or furnace tune-up, involves checking the thermostat, air filter, blower motor, blower current amplifier, circuit board, safeties, igniter, flame sensor, burners, gas pressure, combustion, etc. During the furnace service, if any component faults are discovered, the HVAC professional will advise a repair or replacement as necessary.

  • How often should I change my air filter?

    Most HVAC companies and manufacturers advise changing air filters every two to three months. Replacing your filter regularly can improve air quality and comfort and help prevent gas furnace breakdowns, overheating, and other problems.

  • What is meant by condensing unit?

    Condensing unit refers to a part of a "central air conditioner" that has an outdoor coil, one or more compressors, and an air-moving mechanism and is designed to remove heat collected by the refrigerant and transfer it to the outside environment.

  • Is condensing unit inside or outside?

    The condensing unit is always located outside.

  • What is required to install a mini-split system?

    A heat pump or condensing unit outside, a wall-mounted air handler inside, high- and low-voltage connections, and refrigerant lines running from the outside to the inside system are all required for a mini-split system. To finish the installation, further technical skills are needed, such as verifying the refrigerant charge, making proper electrical connections, fully securing the inside air handler on the wall, etc. That's why we recommend getting in touch with an licensed HVAC company to do the complete mini-split installation.

  • Why is my air conditioner leaking water?

    Some HVAC systems (gas furnace or air handler) leak water from their units both inside and outside as a result of their excessive use in Fairfax homes on a hot and humid day. There are multiple reasons for the air conditioner to leak water. First, due to a lack of airflow in the system, which is caused by a dirty filter and a defective blower motor. A dirty filter that is not changed on a regular basis is the most common cause of a frozen indoor coil and a clogged drain line. We recommend changing the filters every 2-3 months and pouring some bleach or vinegar down the drain line in the spring. Second, having a system low on refrigerant can cause the indoor coil to freeze, which can also result in a water leak on top of the gas furnace, air handler, and water on the floor. Third, the damaged or rusted drain pan of the evaporator coil of an air handler or evaporator coil on top of the gas furnace can result in a water leak. In this situation, water will fall through drain pan holes in the HVAC system and return box, which can cause a pool of water on the floor.

  • Why is my outside AC unit making a humming noise but not coming on?

    If you have an outside air conditioner that is trying to turn on but making a humming noise, that is most likely a defective current amplifier. The current amplifier usually fails due to high heat, a dirty condenser coil, loose electrical connections, and the system's age. We recommend contacting an HVAC company to replace the current amplifier and troubleshoot further if there is any other issue with the HVAC system n Fairfax homes.

  • Can I replace AC capacitor myself?

    We don't recommend changing capacitors if you are not a licensed HVAC technician. Capacitors are very dangerous. They hold the electrical charge even when the power is turned OFF to the system and the wires are disconnected. Our recommendation is to call the HVAC contractor to replace and install a proper-sized capacitor and find the cause of the failure.

  • Why is my condenser fan making a noise?

    A buzzing noise coming from an outdoor fan motor is a sign that the motor is going bad. A weak capacitor can also cause the fan motor to not run and can make the condenser fan motor make a buzzing noise. A dirty condenser coil also causes the condenser fan motor to work hard, which can cause the fan motor to fail prematurely. However, when other parts of the system, such as the compressor or contactor fail, they also make a buzzing noise.



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