Heat Pump being repaired

When it comes to heating and cooling your home, understanding the terms associated with heat pumps and air conditioners is essential. Whether you’re looking to install a brand new system or just need to make repairs to your existing system, having a basic understanding of the terminology will help ensure you make the right decisions. In this article, we’ll cover some of the most important heat pump and air conditioner terms you need to know.

Central air systems 

A central air system is an integrated heating, cooling and ventilation system that is used to condition the air within a home or building. It is typically used in larger buildings such as office buildings, schools, and hospitals, but can also be used in residential homes. 

It utilises ducts and vents to distribute air throughout the home, providing an even temperature in each room. There are two main components of a central air system: an indoor unit and an outdoor unit.

Ductless air systems 

A ductless air system is an efficient and cost-effective way to keep your home cool and comfortable. It is a type of air conditioner that does not require the use of ductwork to distribute cool air throughout a home. Instead, it uses individual air handlers that are typically mounted on interior walls or floors to direct cool air into specific areas of the home.

Ductless air systems are becoming more popular due to their energy efficiency, flexibility, and ease of installation. These systems can be installed in a single room or multiple rooms, allowing you to control the temperature in each space independently. They also require less energy than traditional central air conditioning systems, resulting in lower utility costs.

Split System

The term ‘split system’ is used to describe heating and cooling systems that use an indoor and outdoor unit where the system is split into two units. The outdoor unit contains a compressor, which is responsible for compressing the refrigerant and transferring the cool air to the indoor unit. The indoor unit contains a fan and evaporator coil, which are responsible for distributing the cooled air throughout the room. 

Heat Pump

A heat pump is a name for the heating and cooling system in a residential property. A heat pump is also known as a ductless air system or split system. It is capable of both heating and cooling a home to the desired temperature. 

Heat pumps can come in different forms such as a high-wall mounted unit which is the most common type of heat pump or a floor unit.

Air Conditioner

Air conditioning is often a term used to describe the heating and cooling system in a commercial building. It can also be known as HVAC (Heating Ventilation & Air Conditioning). 

Air conditioning systems work by cooling the air inside a building and removing humidity, which helps to maintain a consistent temperature. The air passes through a series of filters and coils, where it is cooled and dehumidified before being delivered to the interior of the building. In addition to cooling the air, the system can also be used to regulate the humidity levels, ensuring that the occupants of the building remain comfortable.


When it comes to heating and cooling systems, the compressor plays a critical role in the system’s performance. The compressor is a pump that moves refrigerant around the system, allowing the air to be cooled or heated. It helps to maintain a steady temperature in the home or business.

The compressor is powered by electricity and is usually located outside the building, usually on the roof or in a separate unit. It takes the refrigerant, usually a gas or liquid, and pumps it through the system. This process helps to cool the air, as well as heat it up when necessary.


A condenser is an important component of a heating and cooling system. It is responsible for removing heat from the air and transferring it to another medium, such as a liquid or gas. The condenser works by taking in hot and humid air, cooling it, and releasing cooled air into a home or other space. 

In a heating and cooling system, a condenser typically consists of a refrigerant coil and a fan. The refrigerant coil is a set of copper tubes filled with a refrigerant. As hot and humid air passes through the coil, the refrigerant absorbs the heat from the air and changes it from a gas to a liquid. The fan then draws the cooled air over the coil, releasing the cooled air into the space. 

Evaporator Coil

An evaporator coil is an essential component of a heating and cooling system. This coil is filled with cooling refrigerant, and it is responsible for absorbing heat from a home or building, thus cooling the air inside. It is a part of the indoor unit of a split air conditioning system, which is composed of two distinct components: the condensing unit and the evaporator coil.

When the air inside a home or building needs to be cooled, the evaporator coil is used. The refrigerant inside the evaporator coil absorbs heat from the air, which cools it down. This process is known as evaporative cooling. The cooled air is then circulated back into the home or building, providing a comfortable atmosphere.

The evaporator coil is connected to the condensing unit, which is located outside the home or building. This unit contains a fan, a compressor, and a condensing coil. The compressor compresses the refrigerant, which causes it to become hot. The fan then pushes this hot air through the condensing coil, which then releases the heat outside the home or building.


A humidifier is a device that adds moisture to the air in a home or business, usually as part of a heating and cooling system. Humidifiers are often used in climates with very dry air. 

Humidifiers are often used in conjunction with a heating and cooling system to help maintain a comfortable indoor environment. By adding moisture to the air, a humidifier can help keep the air from becoming too dry, which can make it harder for a heating and cooling system to effectively regulate the temperature of a room.


A dehumidifier is an important part of a heating and cooling system. It is designed to reduce the amount of humidity in the air, making it more comfortable and efficient to heat and cool a home.

A dehumidifier works by drawing in moist air and passing it through a refrigerated coil. The warm moist air is then cooled, and the moisture is condensed into water and collected in a collection tray. The now dehumidified air is then returned to the room.

The main purpose of a dehumidifier is to reduce the level of humidity in the home. High humidity levels can lead to a number of problems, including mould and mildew growth, musty odours, and damage to furniture and other materials. By reducing the humidity level, these problems can be minimised.


Refrigerant is a key component of a heating and cooling system. It is a fluid that is used to transfer heat from one area to another. Refrigerant helps to keep a home comfortable by removing heat from the air inside the home and transferring it outside.

Refrigerant is a special type of liquid or gas that is used in a heat pump system to cool or heat a home. It helps to move heat from one place to another, and is usually found in closed systems. It works by absorbing heat from the air inside the home, and then releasing it outside.


Energy Efficiency Ratings (EER) measure the efficiency of air conditioning units and heat pumps. They are used to compare units of different sizes and to identify how much energy they use. The higher the EER, the more efficient the unit is.

EER ratings are determined by dividing the cooling capacity of the unit (measured in BTUs) by the amount of energy used (measured in watts). A unit with a higher EER rating is more efficient and uses less energy than one with a lower EER rating.

EER ratings are important when choosing an air conditioning unit. A higher EER rating means that the unit is more efficient and will cost less to operate. It’s also important to consider the size of the unit, as larger units tend to have higher EER ratings than smaller ones.


Heat pumps and air conditioners are an important part of the modern home, providing comfort and convenience to homeowners. While there are various types of heat pumps and air conditioners, understanding the basic terms and components of each will help you make the best decision for your home. 

By familiarising yourself with the terms related to heat pumps and air conditioners, you can be assured you’re making an informed decision. Whether you’re replacing an old unit or installing a new one, understanding the terms related to heat pumps and air conditioners will help you make the best choice for your home.