The home’s HVAC system is critically important for the comfort and air quality of the home. Homeowners must take proper care of the equipment so it continues to work at peak efficiency. First-time homeowners may be unfamiliar with HVAC fundamentals, and that can lead to skyrocketing utility bills and the need for costly repairs. So, we have put together this HVAC for beginners’ guide to help you understand the HVAC basics that will help keep your system running smoothly throughout the year.
What Is an HVAC System?
HVAC stands for heating, ventilation, and air conditioning. Your home’s HVAC system includes all the equipment responsible for the heating, cooling, and air circulation within your home. The HVAC basics encompass the furnace, the air conditioner, and the ductwork that connects them throughout your home.
While most people think of the HVAC fundamentals as heating or cooling, the ventilation component is essential. Your HVAC equipment forms a closed system. The air within your home is drawn into the HVAC equipment, where it is heated or cooled, filtered, and then returned to your living space.
The air filtration function and ventilation are critical to maintaining your indoor air quality. Dust, mites, pet dander, and various allergens and particulates are filtered out of your home’s air as it is circulated by the “V” in HVAC. Further, the ventilation also helps control moisture levels and humidity in the home while helping to remove odors. The ventilation equipment also manages carbon dioxide and other pollutant levels.
Beyond the heating and cooling we crave, the HVAC system is vital to the health and comfort of the home’s residents.
Essential HVAC Components
Basic HVAC knowledge includes an understanding of the primary system components and what they do, as outlined below:
Refrigerant
Refrigerant is what makes air conditioners produce a cooling effect. It is a chemical in liquid form that absorbs heat as it evaporates. The HVAC system then compresses the refrigerant back into a liquid, expelling the absorbed heat outdoors.
Evaporator Coils
Evaporator coils in an HVAC system consist of copper tubing that carries the refrigerant. As the system draws in air from the home, this air passes over the cold evaporator coils. The heat from the air is absorbed by the refrigerant in the coils, causing the refrigerant to evaporate within the coils. This process removes heat from the air, cooling it. The cooled air then circulates back into the home. These HVAC basics for cooling air apply to all air conditioners.
Compressor
After the refrigerant absorbs heat from the home’s air and evaporates in the evaporator coils, it enters the compressor as a gas under low pressure. The compressor increases the gas’s pressure and temperature, preparing it for the condenser.
Condenser
The refrigerant enters the HVAC condenser as a gas under high pressure. As it passes through the copper condenser coils, the refrigerant releases its heat, cooling it down so it reverts to a liquid form. The condenser unit is located outdoors and releases the heat into the environment.
Furnace/Heat Pump
The heating in a traditional HVAC system is done by a furnace that heats the air. Newer systems in mild winter climates use a heat pump in place of the furnace and the air conditioner. Heat pumps utilize the HVAC compressor and condenser for cooling, as described above, and then they reverse the action for heating.
Ductwork
The HVAC system ductwork circulates the air in your home through a series of ducts or conduits.
Vents
A vent is the opening where the ductwork allows air to pass into the home. Your home might have vents in the ceiling, floor, and walls.
Blower Motor
The HVAC blower motor turns the fan that circulates hot or cold air throughout your home.
How Does an HVAC System Work?
Now, let’s put the HVAC basics together. The blower motor draws your home’s air into the HVAC system. The air is drawn over the evaporator coils, where it sheds heat to the refrigerant in the coils. Then, the cool air is blown through the ductwork and out the vents into your home. For heating, in systems with a furnace, the air passes over a heat exchanger, which warms the air before it circulates back into your home. With a heat pump, the heating process is the reverse of the cooling.
Types of HVAC Systems
Armed with this basic HVAC knowledge, let’s briefly review several types of HVAC systems.
Cooling & Heating Split Systems — Central
The traditional HVAC system used in the U.S. is the cooling and heating split system, commonly referred to as “central air.” It consists of an indoor unit with the furnace and evaporator coils and an outdoor unit that houses the compressor and condenser.
Hybrid Split Systems
The hybrid split HVAC system is a newer, more energy-efficient system for mild winter climates with moderate temperatures. They combine a traditional gas furnace with an electric air-source heat pump. The system then switches between gas and electric power to optimize efficiency based on the prevailing weather conditions.
Ductless Mini-Splits
The ductless mini-split is a newer and smaller version of the classic HVAC split system that works without ducts to circulate the air. Hence the name “ductless mini-split.” They have an outdoor unit containing the condenser coils and compressor and an indoor unit housing the evaporator coils and fan. Electrical wiring and refrigerant tubing connect the two units, delivering heated or cooled air directly to specific rooms.
Packaged HVAC Systems
Packaged HVAC systems combine all their components into a single outdoor unit. These are used in places with limited space for indoor HVAC components.
Geothermal HVAC
Geothermic HVAC systems are modern, highly efficient heating and cooling systems. They harness the naturally stable temperature of the earth itself for heating and cooling through a series of underground pipes.
Difference Between HVAC and Air Conditioning
Now that you’ve mastered HVAC basics let’s have a quick quiz: What’s the difference between HVAC and air conditioning? An HVAC unit contains heating, ventilation, and air conditioning equipment. Air conditioning refers solely to the equipment that cools the air in your home.
Stay Comfortable Year-Round With Professional HVAC Services
At Aire Serv®, we do more than teach homeowners HVAC basics. Our service professionals deliver comprehensive HVAC services throughout the country. Our heating and cooling services include installation, maintenance, repair, and replacement of every component of your system. Trust your local Aire Serv for your residential or commercial HVAC services.
As proud members of the Neighborly community of home and business service brands, all our work is backed by the Neighborly Done Right Promise®. We know the job isn’t done until it’s done right.
Contact your local Aire Serv today to request an appointment.
This article is intended for general informational purposes only and may not be applicable to every situation. You are responsible for determining the proper course of action for your home and property. Aire Serv is not responsible for any damages that occur as a result of this blog content or your actions. For the most accurate guidance, contact the Aire Serv location nearest you for a comprehensive, on-site assessment.
FAQs About HVAC for Beginners
As an industry leader and a brand that is trusted by homeowners and businesses nationwide for our knowledge and experience, we’re happy to answer your HVAC questions. Here are answers to some of the frequently asked questions about HVAC system basics.
What does HVAC mean in air conditioning?
HVAC refers to Heating, Ventilation, and Air Conditioning. An HVAC setup includes the overarching system that controls the temperature, humidity, and air quality in indoor spaces.
While AC specifically focuses on cooling the air, HVAC encompasses a broader range of technologies. These include furnaces, heat pumps, and boilers for heating; ventilation systems for air exchange and purification; and air conditioners for cooling and dehumidifying.
Air conditioning is a key component of an HVAC system, working in conjunction with heating and ventilation to create a comfortable and healthy indoor environment.
What are the signs that my HVAC system needs maintenance?
Like any appliance, your heater, AC, and ventilation systems need upkeep to maintain efficiency. The following telltale signs can indicate your HVAC system requires routine maintenance or repairs:
- Strange noises: Unusual sounds like banging, rattling, or whistling during operation often indicate loose parts or mechanical issues.
- Uneven temperatures: If some rooms are noticeably warmer or cooler than others, your system might have airflow problems or zoning issues.
- Increased energy bills: A sudden spike in your utility costs without a change in usage could signal that your HVAC is working harder than it should due to inefficiency.
- Weak airflow: Reduced airflow from vents suggests a blockage in the ductwork or a problem with the blower motor.
- Unusual odors: Musty or burning smells coming from your vents can point to mold growth, dust buildup, or electrical problems.
- Frequent cycling: If your system turns on and off more often than usual, it could indicate a dirty filter, a refrigerant leak, or an oversized unit.
- Visible leaks: Any signs of refrigerant or water leaks around your indoor or outdoor units require immediate attention.
An Aire Serv Advantage Plan Membership provides a routine maintenance plan that can help prevent unnecessary future repairs.
How often should I replace my HVAC air filter?
General guidelines say to replace your HVAC air filter every 1 to 3 months. However, the ideal frequency depends on the type of filter, your lifestyle, and the presence of contaminants in the air. If you have pets or suffer from allergies, you might need to replace the filter more often, perhaps every 30 to 60 days.
Can HVAC maintenance reduce energy bills?
Yes, regular HVAC maintenance can significantly reduce your energy bills. Dirty filters, clogged coils, and unlubricated parts force your HVAC to work harder, consuming more energy to achieve the desired temperature. A well-maintained system operates more efficiently, often requiring less active running time.
Is upgrading to an energy-efficient HVAC system worth it?
Upgrading to an energy-efficient HVAC system can be a worthwhile investment for several reasons.
First, you'll likely see a significant reduction in your energy bills. Energy-efficient systems are designed to consume less power while providing the same level of comfort. Over time, these savings can offset the initial cost of the new unit. Some studies suggest potential energy savings of up to 20% to 50% compared to older, less efficient systems.
Second, newer, energy-efficient models often come with enhanced features that improve comfort and air quality. This can include more consistent temperature control, better air filtration, and quieter operation.
While the upfront cost of an energy-efficient HVAC system can be higher, various factors can make it more manageable. Government and local utility companies often offer rebates and incentives for installing energy-efficient appliances. Moreover, upgrading can increase your home's value, which is a plus if you plan to sell in the future.
The payback period, which is the time it takes for your energy savings to equal the cost of the upgrade, can vary. However, with rising energy costs and potential incentives, many homeowners find that the long-term benefits outweigh the initial investment. Consult with an HVAC professional to assess your specific situation and determine possible savings and payback period for your home.
Does a programmable thermostat save on heating and cooling costs?
Yes, a programmable thermostat is a smart way to save on heating and cooling costs. It allows you to customize your home's temperature based on your schedule, automatically adjusting when you're asleep or away. This prevents your HVAC system from running at full capacity unnecessarily.
For example, you can program the thermostat to lower the temperature in the winter while you're at work and raise it shortly before you return. The same principle applies in the summer—set the thermostat to allow higher temperatures while you're out and cool things down before you get home.
Why is my HVAC system making strange noises?
Strange noises coming from your HVAC system are often indicators of underlying issues that need attention. Here are some common reasons why you might be hearing unusual sounds:
- Rattling: Could indicate loose panels, debris caught in the blower, or ductwork issues.
- Banging: Might suggest loose components, problems with the ductwork expanding and contracting, or even issues with the compressor.
- Whistling: Often points to restricted airflow due to a dirty filter or blocked vents. It could also be a sign of a refrigerant leak.
- Grinding: Could indicate problems with the motor bearings in the blower fan or the outdoor condenser fan.
- Clicking: May be normal during startup or shutdown, but persistent clicking could signal electrical issues or a failing capacitor.
- Hissing: Often a sign of a refrigerant leak, which requires immediate professional attention.
Ignoring these noises can lead to more significant damage and costly repairs down the line. Have a qualified HVAC service professional inspect your system if you notice any persistent or concerning sounds.
Is my HVAC system sized right for my home?
A professional HVAC service professional can perform a "Manual J" load calculation to determine your home’s precise heating and cooling needs based on the square footage, insulation, window efficiency, and local climate. If your system was installed without this calculation, it could be the wrong size. Observe comfort levels and energy bills over time for clues that your system fits your home.
- Temperature: Check for consistent temperature throughout your house without excessive cycling (frequent short bursts of operation). Rooms that are consistently too hot or too cold suggest an improperly sized unit.
- Energy bills: An oversized unit might cool or heat the space quickly but cycle off before dehumidifying properly, leading to discomfort and wasted energy. An undersized unit will run constantly, struggling to reach the desired temperature, increasing energy consumption and wear and tear.
How long do HVAC systems last?
On average, a well-maintained system can last anywhere from 10 to 20 years. However, this is just a general range, and several elements can influence the actual lifespan:
- Maintenance: Regular maintenance, including filter changes and professional tune-ups, is the most significant factor in extending the life of your unit. Neglecting maintenance can shorten its lifespan considerably.
- Usage: Systems that run more frequently due to extreme temperatures will naturally experience more wear and tear.
- Quality of installation: An improperly installed system is more likely to have problems and a shorter lifespan.
- System type: Furnaces and boilers often last longer than air conditioning units or heat pumps.
- Climate: The local climate can impact lifespan. Areas with high humidity or coastal regions with salty air can be tougher on HVAC components.
- Air quality: Dusty or polluted air can cause components to wear out faster. Change air filters regularly to help mitigate air quality issues.
By investing in regular maintenance and addressing issues promptly, you can help your HVAC system reach its maximum potential lifespan.
