What Size Air Conditioner Do I Need?

Air Conditioner BTU, design, placement, and personal needs are all things you need to think about when considering what size air conditioner you need for your business. Buying an air conditioner is an expensive investment, so it’s important to get it right so as not to spend more money than you need to. 

This article will explain how to figure out what size air conditioner you need and hopefully help to get you on your way to installing an air conditioner in your business.

Initial Considerations

Firstly, you should ensure you’ve given yourself enough time to install your system. Installing any size air conditioner will take longer in a commercial building than in a domestic setting, discounting the availability of installation engineers. Fortunately, Autumn is the best time to install air conditioning because as the weather begins to cool, most would consider it pointless to buy an air cooling system. By purchasing an air conditioner when demand is low, you’ll have more time to think about your options and choose the best for you


Secondly, the potential placement of your air conditioner is very important to contemplate. This can affect whether you install external air conditioning and the size you need. Depending on your space constrictions, you could choose to purchase a portable air conditioner, wall mounted, suspended, etc. This will also affect the air conditioner BTU of your system.

Air Conditioner BTU

BTU is an acronym for British Thermal Unit and correlates to the size of the room you’re trying to cool down. If your room is small, your air conditioner BTU will be lower, and if you have a larger room, your air conditioner BTU will be higher. BTU is also reliant on the shape of your room and will not work optimally if you don’t purchase an air conditioner with the correct BTU.


If you want to cool down medium or large rooms, it is advisable to install Central Wall Mounted Air Conditioning. This is only possible if you have a lot of space for installation, such as a loft or basement where the central unit can be placed in. Central units are large and will need sufficient space to be able to circulate tempered air throughout your building. Additionally, these use external air conditioning pumps called Compressors to ventilate and provide chilled air. 

If you have small rooms, Split Wall Mounted air conditioning is ideal for those who don’t have a lot of space but still need air cooling. This system usually consists of one external unit and up to 5 small internal units. The size of this system is much smaller than Central Wall Mounted Air Conditioning. 

Finally, if you’re trying to cool a large open-plan room, you may benefit most from a ceiling cassette unit. These systems are very powerful, blow streams of air in all directions, and can cool a large room very quickly. The only problem with these systems is that they need to be able to recess into the ceiling. So, unless you have a deep ceiling, you may find it difficult to install this type of air conditioning. 

What can we do for you?

We at Chillaire have accumulated over 2000 clients in the 30 years we have been in business and cover everything from initial consultancy to installation and maintenance. So, in addition to taking care of installing your system, we can also advise you further on your options and provide you with an informed and experienced opinion. Why not contact us today to speak to one of our highly-trained engineers? 

Air Conditioning - Heating - Ventilation