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what is hvac

What Is an HVAC System and How Does It Work?

If you're like most homeowners, then you know what an HVAC system does for your home. However, understanding HVAC systems and how they work is a very different matter.

Whether you want to just make sure you've got the right system for your current home or you are trying to figure out what would be a good option for your next system, HVAC consulting can help you figure it all out.

What Is HVAC?

Do you wonder: what does HVAC stand for? It's an acronym for heating, ventilation, and air conditioning. It's the system that heats or cools air and moves it around a residential or commercial building to maintain consistent temperatures inside that have been chosen by the user.

HVAC Equipment - Heating

Many homes use a furnace to get their heating. These furnaces come in many different kinds and also use various fuels, including geothermal energy, oil, propane, electricity, and natural gas. It's very common to see natural gas furnaces, but electric models are sometimes more prevalent in regions with mild winters or have high gas costs. Heating equipment often has a blower motor that forces air through the ductwork. This helps it reach all parts of the residence.

HVAC Equipment - Ventilation

what does hvac stand for

Ventilation involves the attached systems that process and move the air throughout the overall HVAC system and your home. This might include ventilation shafts, ductwork, and vents in the ceiling, walls, and floor. Insufficient ductwork will prevent a system from heating or cooling a home, and there might be cold or hot spots without enough ductwork. Ductless systems don't have advanced ventilation components, and they're typically reserved for single spaces, such as one room, an attic, or a basement.

HVAC Equipment - Cooling

An HVAC system will usually have an air conditioner for a residential property. A commercial property might have several air conditioners. Heat pumps can also be useful since they work a lot as air conditioners do. In fact, many heat pumps can heat or cool a home. When a heat pump is in place, it's often paired up with an electric furnace. The furnace supplements the ability of the heat pump to warm a home. Air conditioners are typically but not always paired with a gas furnace to provide the right balance of heating and cooling.

How Does HVAC Work?

what is a hvac system

An HVAC system moves air. That usually centers around moving warm air. That warm air might be moved out of a home so it can cool down, but it might also be moved into a home to maintain heat. While it's good to have HVAC basic knowledge on your own, there might be times that you need a mechanical engineering company.

How HVAC Heating System Works

A heat pump will absorb heat from an outside unit and then transfer it inside the residential home. A furnace will generate heat either by using electricity or a fuel source.

How HVAC Cooling System Works

Air conditioners and heat pumps don't create cold air so much as they take heat from inside the home and force it outside. The secret to this is having the right refrigerant in the system.

How HVAC Ventilating System Works

Ductwork is what connects the heating and cooling components of any HVAC system but also exterior components outside and in every room of a home. This is how air gets moved where it needs to be.

Other Elements of a HVAC System

what is hvac

Knowing the parts of a home HVAC system helps you get a sense of the complexity of it all. All these parts need to be functioning at high capacity in order for the whole system to be effective at regulating temperature in a home.


The thermostat is one of the most frequently accessed residential HVAC systems components in house HVAC systems. This is where you set your desired temperature with either an analog or digital device at the point you would stay comfortable.

Evaporator Coil

When you set your thermostat to a lower temperature, the evaporator coil is what cools the air down. The heat is removed as part of the humidity and moisture being expelled outside, while the dryer, cooler air is pumped back into your home.

Condensing Unit

This unit is outside your home and filled with the designated refrigerant gas. When the gas takes liquid form, this device's function is to send it to the evaporator to turn into a gas form once more.


These are outlets that let the ductwork push cooled or warmed air into the rooms of your home. There are many spots they may be, but you need to make sure they stay unblocked wherever they are placed.

Refrigerant Lines

These lines will carry refrigerant to the system's condenser unit when the refrigerant is a gas. When the gas converts back to liquid form, it is then sent back to the system's evaporator coil.

Furnace HVAC System

A furnace is usually going to be the single-largest component of an HVAC system and takes up a lot of room. It's responsible for heating the air you need to be warm, and it can use a variety of different energy sources to accomplish this.


This is the transport system for air throughout a home. Modern homes take ductwork into consideration before construction so the vents can be hidden behind ceilings and walls.

Air Return

house hvac systems

An HVAC system's air return part draws air into the whole system via a filter. Without this, air would not move through the system. A clogged or dirty filter can impact the performance of the whole system.

Exhaust Outlets

Vent stacks and chimney flues are examples of exhaust outlets. However, any place where heat gets vented from the home qualifies as one of these components.


Furnaces typically have a filter of 1 to 4 inches. That filter traps particles that would enter and go through your system. It's crucial that you change or clean these filters on a routine basis.

Humidity Control Products

Humidifiers and dehumidifiers are often forgotten components, but they are also potentially important to an HVAC system. They reduce the burden on heating and cooling components.

Electrical Components

Every major piece of an HVAC system has to relay information to other system components. This is especially true for multi-speed pieces that make automatic adjustments based on temperature.


Heat pumps and air conditioners have these, and they regulate the refrigerant pressure. Compressors need regular maintenance to prevent breakdowns since they work quite a bit when a system is active.

Types of HVAC Systems

The kind of HVAC system appropriate for a home might depend on many factors, including the age of the home, its size, and its location. An HVAC engineer or technician can help you ascertain which type of HVAC system is right for your residence.

Heating and Air Conditioning Split System

hvac basic knowledge

This is the traditional system with the AC outside the home and the furnace inside. The components are all linked by electrical systems for communication and power and share a ductwork network to move air around.

Hybrid Heat Pump

In this system, a heat pump would normally heat the home until it gets cold enough that the furnace needs to take over. This 1-2 punch keeps a home warm in all situations without using as much energy.

Duct-Free Split System

As the name says, this system has no ductwork. That's very helpful to homes that don't have any room for ducts, and these systems can be powerful options for individual rooms.

Ducted Mini-Split

When homes don't have enough room for traditional ducts, a ducted mini-split system can use tubes to move the conditioned air into the rooms that need it.

Zoned Systems

A zoned system lets you control the airflow to various parts of your home by using valves or dampers to restrict the movement of air through different ducts. By heating or cooling only certain rooms, you can save a serious amount of money and energy.

Packaged System

In a packaged system, all the components are installed outside the home. This is advantageous for a home that doesn't have room inside for system components and is short on space.

Humidity Control

With humidity control, you can adjust not just the temperature but the actual humidity level in your home. You might hear some people joke about dry heat feeling more comfortable, but it's true. Cool, dry air feels better than cool, moist air.

Choose the Right-Sized System

residential hvac systems

Don't get a system too powerful for your home. The cooling cycles would end prematurely, and that can risk condensation, mold, mildew, and other humidity-related problems in your home that you don't want.

Common HVAC Ratings and Certifications

If you're looking at buying an HVAC system, then you're going to see a lot of different ratings involved. Knowing what they are and what they mean makes you a more informed shopper who can make better decisions when buying your home.


AHRI stands for Air Conditioning, Heating, and Refrigeration Institute, an independent organization that offers accurate and objective SEER ratings for many HVAC systems. They make sure that manufacturer efficiency claims are valid.


AFUE stands for Annual Fuel Utilization Efficiency which measures how efficiently a gas furnace turns its fuel into energy.


EER stands for Energy Efficiency Ratio which measures the efficiency of a cooling system at certain outdoor temperature levels. Higher ratings indicate more efficiency.


Seasonal Energy Efficiency Ratio is a measure of how efficient heat pump and air conditioner cooling is. Higher ratings indicate more efficiency. Federal minimums are 13 to 14, but rankings might be as high as 25.


Heat Seasonal Performance Factor measures how efficiently heat pumps actually heat a home. Higher ratings are better.

MERV Rating

understanding hvac systems

Minimum Efficiency Reporting Values are standard measurements of air filter efficiency. Higher MERV ratings indicated finer filtration systems. This is critical to clear airborne contaminants your family might otherwise inhale.

NATE Certification

North American Technician Excellence is a nonprofit certification program HVAC professionals can go through. NATE certification is something to look for in HVAC technicians that you hire.

Who Can Service HVAC Equipment?

Keeping your system running and running well doesn't just help you save money. It keeps your home comfortable and physically safe for those that might do well in serious temperature swings or unhealthy air. Whether your system is residential or one of the many commercial sectors we serve, you may need help sooner or later with your HVAC equipment. If so, then contact us for help in the Calgary area.

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