Best Home Central Air Conditioners for Energy Efficiency

Understand the factors that affect the energy efficiency of central air conditioners at home and discover the top 5 brands of energy-efficient central air conditioning systems.

In many hot, humid and tropical climates throughout the world, air conditioning provides essential comfort in indoor environments. But air conditioning systems can also prove very costly to run. Today’s central air conditioners tend to be more eco-friendly and energy efficient than their predecessors. However, choosing the wrong type of system for your property can lead to unnecessarily high electricity bills.

When trying to strike the balance between providing indoor comfort and managing revenue, it will be essential to do your homework when deciding upon a central air conditioning system. You should first understand how these systems work and then you can discern which factors will affect energy efficiency.

How Central Air Conditioners Work

Residential central air conditioning system.
Residential central air conditioning system; This Old House.

Very simply, through an installed system of supply and return ducts, central air conditioning systems circulate cool air throughout a building, maintaining a constant air temperature and reducing humidity in damp climates. A register or grille is installed wherever you want your cool air output. The placement and size of these registers will be critical to the efficiency of the central air system.

Types of Central Air Conditioners

There are two main types of air conditioning systems – packaged central air conditioners or split-type systems. The size of your building, desired cooling requirements, and whether you already have a preinstalled ductwork system will help to determine which type of central air system is most cost-effective for you.

1. Packaged Air Conditioning Systems
Packaged air conditioning units outside homes.

With packaged air conditioning systems, all of the working parts, such as the compressor, condenser and evaporator, are in one outdoor unit. Air ducts are placed along exterior walls or on the roof, drawing in warm air which is then cooled within the unit and dispersed through the building’s ductwork to the output vents.

2. Split-Type Central Air Conditioners
A split-type central air conditioner.

Split-type central air conditioners instead have several separate components, placed in units both indoors and outdoors. Air from the external compressor unit is sent through tubing to the internal air handler, after first passing through the evaporator coil unit which cools and dehumidifies the air. This type of system can operate with or without the installation of ductwork.

Whilst packaged systems produce less indoor noise, all components face exposure to the outdoor elements. With split-type central air conditioners, because some of the components are placed indoors, when installed correctly it tends to be the more energy efficient system.

Factors Affecting AirCon Energy Efficiency

a) Size of Air Conditioning System

Choosing the correct sized system for your property is absolutely imperative for energy efficiency. Too small a system and it will have to work harder to maintain a consistent temperature, thus costing you more than it should. A system that is too large will lead to damp, clammy air which is not ideal for a comfortable indoor environment. Not to mention spending unnecessary money on a large air conditioning system.

b) Energy Efficiency Rating
Energy Efficiency Rating chart.

Most modern systems will come with a clear energy efficiency rating. By comparing this information across brands, you can make a more informed decision. The higher the energy rating of a central air system, the greater the efficiency. Every year, the European Commission assesses the energy efficiency of air conditioning brands with government approved energy labels. Referring to this study will aid you in your search for the most energy efficient central air conditioning system.

c) Size and Placement of Vents

The vents in central air systems, also called registers, perform two tasks – output and return. Registers designed to expel cool air should be placed near windows and doors, where cooling loss occurs most. As the air warms in a room, return registers draw it back into the cooling system. These types of vents should be placed nearest the centre of the building, on a wall or ceiling, for greatest efficiency.

If the installed vents are too small, the central air conditioning system will have to work harder and faster to effectively cool the air. Therefore, ensuring the correct register size for each room will be essential in maximising the system’s energy efficiency.

d) Register Dampers

If you are installing a central air conditioning system in a large building, dampers in the system will allow your air conditioner to run at peak efficiency by shutting off the air to unused areas. Dampers can be opened or closed as required and can also prevent cool air from entering during colder months. This type of control over the central air system leads to lower running costs overall.

e) Inverter Technology
Diagram comparing Inverter AC and Non-Inverter AC.

If central air conditioning units are fitted with DC Inverter technology, this allows the system to operate more efficiently and economically. Ambient air temperatures are checked by a micro-controller and the air conditioning unit adjusts the temperature accordingly. Unlike older aircon systems, those fitted with this type of technology avoid costly system restarts by controlling the speed of the fans and motors and continually regulating the temperature.

f) Regular Maintenance
Air conditioner maintenance and service.

No matter what type is installed, all central air conditioning systems should be serviced at least once a year by a professional. To ensure optimal working efficiency, it is important that the vents are cleaned, debris is removed, and old parts are replaced periodically. A well-maintained system is a more energy efficient system.

Top 5 Central Air Conditioners for Energy Efficiency

1. Daikin

Daikin branded central air conditioning units.

Dubbed as “air specialists”, Daikin have been serving the public’s aircon needs since 1924. Their expertise in the realm of air conditioning has led them to become an industry leader. Daikin air conditioning units all feature a high energy efficiency rating, with 23 of their products appearing European Commission’s approved products list. Even their more basic, cost-effective offerings can be retrofitted with energy-saving DC Inverter technology to help reduce your energy bills.


Panasonic branded central air conditioning units.

By sheer expansiveness of range, last year Panasonic aircon products made the European Commissions list nine times. Most of the products in their vast central air conditioning range run at top energy efficiency. Pioneers in technological advancements, they also offer systems fitted with intelligent eco sensors. Be it indoor or outdoor units, commercial or residential, packaged or split type, Panasonic have an energy efficient solution to fit your requirements.

3. LG

LG branded central air conditioning units.

Perhaps best known for their mobile phone and television technology, LG also manufacture ultra-modern air conditioning systems and central air units, eleven of which appear on the list approved by the European Commission. They focus on aesthetically pleasing, streamlined units, many with built-in Wi-Fi capabilities. LG will provide a 21st century central air experience.


Mitsubishi Electric branded central air conditioning units.

Early adopters of products to make indoor life more comfortable, Mitsubishi Electric began selling electric fans in 1921. A world leader in both commercial and residential air conditioning solutions, the Mitsubishi Electric range of air conditioners is broad enough to be a one-stop-shop for even the most complex of internal environments. Making the EC’s energy efficiency approved list five times, they produce a varied range of modern central air systems to suit all homes.

5. Toshiba

Toshiba branded central air conditioning units.

Toshiba’s mission appears to centre around improved energy efficiency and providing environmentally responsible products. Their high-technology offerings can be installed for a vast range of property types and needs. Toshiba central air conditioning systems feature on the EC list thirteen times.

There are hundreds of top-quality brands that produce energy efficient central air conditioning products, perhaps making the decision seem overwhelming. But, by understanding your own building’s requirements and the factors that can affect energy efficiency, you will be able to choose the ideal central air conditioning system for your needs.