HVAC Systems: A Comprehensive Guide - Whole Home Scenting


Everything You Ever Wanted To Know About HVAC Systems: A Guide

HVAC system

If you Google “HVAC meaning,” you will see that this acronym refers to a heating, ventilation and air conditioning system. An HVAC system controls the temperature, in some cases the humidity, and the cleanliness of the air inside a building. HVAC refers to the different systems that are utilized to transport air between indoor and outdoor areas. HVAC systems ensure you are cool during the summer months and warm during the winter, and they also filter the air to keep indoor humidity at a safe level. Such systems ensure warm and cold air are distributed evenly throughout a system of ducts and vents inside a building or home. Unlike air conditioners, HVAC systems are capable of both heating and cooling a space. Learn moure about how they work here.

What Is HVAC?

HVAC repairman

The primary components of a system include the following:

  • Furnace:

    The furnace is generally the largest part of an HVAC system. Furnaces can typically be found in areas of a building or home such as a basement or a room dedicated solely to an HVAC system. Furnaces feature burners and an ignition, both of which are responsible for heating the air. The air is moved through the heat exchange, through the ducts and then into the various rooms of a building.

  • Heating:

    The heating components of an HVAC system usually consists of a gas and electric furnace or a heat pump. HVAC systems that utilize both electricity and gas are known as “split systems.”

  • Heat Pump:

    Unlike the furnace, the heat pump takes warm air from outside and sends it through an evaporator coil. The coil absorbs heat from a cold environment and releases it to a warmer one by transferring thermal energy in the opposite direction of the spontaneous heat transfer. The heat pump also transfers energy to a heat sink using external power.

  • Air Conditioning:

    Air conditioners cool the air and monitor the temperature inside a building using a thermostat; they also help control humidity. Most HVAC systems feature a split-system A/C, meaning one part of the system is inside and one is outside. The compressor and condenser are located outside while the evaporator and expansion valve are inside.

  • Ventilation:

    Ventilation systems move air while removing excess moisture and harmful particles from the air. All of the exhaust fans, filters, air ducts and air vents are a part of the ventilation system. Ventilation systems work by transferring the air from the cooling or heating appliance throughout the ducts of a building or home and then transferring the air back using rectangular covers. Indoor air quality is an important consideration for your health.

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Types of HVAC Systems


There are four primary types of HVAC systems:

1. Standard Split Systems

Standard split systems have one component installed inside the building or home and another installed outside. Such systems are the most popular residential HVAC systems today, and they can be configured in a variety of ways.

Furnace and air conditioner configurations employ a gas or oil furnace, and the configuration is extremely efficient and better suited for warm climates. The air conditioner’s condensing unit is installed outside while the furnace is installed inside. The evaporator coil is a key component of the system, and it is usually placed inside the furnace cabinet. It uses refrigerant and copper lines to capture heat and send it inside the building.

2. Hybrid Systems

Hybrid systems, also known as dual-fuel systems, are better suited for cold climates. When the weather is cool, the heat pump supplies the heat. When temperatures are below freezing, the gas furnace supplies the heat.

Air handler and heat pump systems are best for individuals living in hotter regions where freezing temperatures are rare. As their name suggests, the system’s heat pump supplies both cool and warm air. The heat pump functions similarly to an air conditioner, but it can be reversed in cold weather. The system also uses an air handler with a blower motor instead of a furnace.

3. Packaged Systems

Packaged systems feature all the main components of an HVAC system stored in a single cabinet. Homeowners who do not have the luxury of a basement often prefer packaged systems since they are mounted outside. The air is transferred from the outside of a house to inside the house using a blower (which brings in untreated air). Depending on the unit, the method for treating the air will vary.

4. Geothermal Systems

Geothermal HVAC systems heat and cool using the temperature of the earth. The water in the system contains a refrigerant that is circulated through pipes installed in groundwater, allowing heat to collect. The collection of heat in winter and the removal of heat during the summer is facilitated by the near-constant temperature of the ground.

5. Ductless Split Systems/Ductless Mini-Split Systems

Ductless split systems use an air conditioner or heat pump installed outside. The air conditioner is used only for cooling while the heat pump can be used for both heating and cooling. Furnaces are not used in ductless split systems, so the indoor components are installed on walls, ceilings or floors, and a fan circulates treated air.


HVAC ventiliation air filter

HVAC systems either utilize the air inside or outside a building using a process known as ventilation. There are two distinct types of ventilation:

  • Natural Ventilation – Natural ventilation is used in most buildings with doors, vents, windows and other types of openings. The air moves naturally in and out of the building or home through these openings. Unfortunately, it is difficult to remove carbon dioxide, excess moisture or unpleasant odors using natural ventilation.
  • Mechanical Ventilation – The “V” in HVAC actually refers to the mechanical ventilation used to ventilate buildings. In the past, cracks, gaps and a larger number of windows and doors in buildings made natural ventilation a better option, but modern homes are now more tightly sealed.

Once the air is transferred in, it is drawn into a handling unit. From there it is filtered to remove dirt, allergens, dust, and other particles. Excess humidity is then removed and the air is heated or cooled. Finally, the air is dispersed throughout the building using a network of ducts and vents.

How Much Does It Cost To Install an HVAC System?

HVAC system with water heater

Before choosing an HVAC system, homeowners should consider the overall costs associated with a system’s installation and maintenance. The price of a new HVAC system can range from $3,000 to $30,000 or more depending on the size of the house, efficiency of the equipment, length of the ductwork and a homeowner’s residential area. Homeowners should choose an established HVAC company to install their system, especially since improperly installed systems can be expensive to repair in the future.

Since heating and cooling contribute to the energy bill of every homeowner, those considering purchasing an HVAC system should make sure their homes are well insulated and airtight.

With so many choices, it can be difficult to find the right system, especially since each system has its advantages and disadvantages.

Packaged vs. Split HVAC Systems

Packaged systems do not generate as much noise since most of their components are installed outside. They are also compact and cost less to install. Unfortunately, they do not offer as many options as ductless and standard split systems. They are also far less efficient, and they sustain wear and tear faster than other systems (since the units are outside, they are more susceptible to the elements). It is also possible for wild animals to take up residence inside a unit, especially during the colder months.

Split HVAC systems, on the other hand, offer a wider range of options, and they are more affordable than packaged systems They are also easier to operate and control and are extremely energy efficient. Unfortunately, installing the necessary ductwork for a traditional split system can be astronomically expensive if it does not already exist. They are also noisier and more difficult to install (installation must be done by a professional).

Air Circulation

Floor vent

HVAC systems are responsible for circulating air throughout a building. To properly circulate air, HVAC systems must have the right ductwork to distribute the air in the most economical and direct manner. Air terminal units such as diffusers and grilles can supply air at a low velocity. Fan-powered terminal units use an integral fan to supply a space with air. Variable-volume terminal units are capable of delivering a variable amount of air into a building. All piping and ductwork should be insulated to save energy and prevent heat loss. Buildings and homes must also have sufficient ceiling space to install ductwork.

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Central HVAC Systems

Central HVAC systems can serve multiple thermal zones, and most of their major equipment is installed outside the served zones either inside, adjacent or on top of the building. Central systems condition zones with their equivalent thermal load, and they have several control points throughout a building, such as thermostats.

A central HVAC system transfers thermal energy in the form of air, water or both. They also include water-source heat pumps in addition to cooling and heating panels. The air handling unit contains a reheat coil, cooling coil, preheat coil, humidifier, filter and mixing box, as well as return and supply fans and outdoor air.

All-air systems, as their name suggests, use air to transfer energy throughout a building. All-air systems can be classified based on the zone they serve.

Single-Zone HVAC System

A single-zone system consists of a heating and cooling source, distribution ductwork, air handling unit and necessary delivery devices. The air handling units can be integrated in the same location as the cooling and heat sources, or they can be integrated separately where they are detached. Integrated packages are most commonly installed on the rooftop and connected to ductwork so they can deliver air into spaces within the same thermal zone. Single-zone systems are designed simply and are relatively low in cost and maintenance compared to other systems.

In a single-zone all-air HVAC system, there is only one control device, such as a thermostat, located in the zone of operation. The control may be either on-off or modulating to meet the thermal load of the system. This can be achieved by adjusting the output of the heating and cooling source within the packaged unit.

Multi-Zone HVAC Systems

In a multi-zone all-air system, a supply air duct is provided for each zone of a building. Hot and cold air are mixed together in the air handling unit to maintain a certain temperature in each zone. Each zone has conditioned air that is not mixed with the air in other zones, and each zone has a different thermal requirement. Multi-zone all-air systems consist of an air handling unit with a parallel flow path through the heating and cooling coils and internal mixing damper.

A multi-zone all-air system should serve no more than 12 zones due to physical restrictions on damper size and duct connections. If more zones are needed, additional air handlers can be used. Multi-zone all-air systems can condition several thermal zones without wasting energy. Unfortunately, there can be leakage between the decks of an air handler, which can reduce energy efficiency.

All-Water HVAC Systems

All-water systems distribute hot and cool water from a central system to conditioned spaces. All-water systems are small in comparison to other systems, primarily because they use pipes as distribution containers; the water they use has a higher density and heat capacity than air, so the lower volume will transfer heat. All-water systems are rarely mounted on the ceiling and are commonly installed on the floor.

Air-Water HVAC Systems

Air-water systems are a type of hybrid system that combines the benefits of both all-air and all-water systems. The combined system has a reduced volume, and outdoor ventilation properly conditions the desired zone. The water medium carries the thermal load through the hot and cold water, while the air medium conditions the rest.

Learn More About Us

HVAC systems can truly make your house a home. They can ensure you and your family remain comfortable no matter the weather outside. Here at Whole Home Scenting, we strive to ensure your HVAC system produces a wonderful smell throughout the day with our whole home scenting system. Choose from an assortment of fragrance oils and learn to pick the best fragrances for your own home To learn more about who we are and what we do, contact us at 855-SCENT-ME.

Photo credit: Pixabay (candle and labeled essential oil bottle), Mareefe (fragrance bottle and bath salts), Linda Prebreza (body scrub), Palo Cech (blooming purple flowers)
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