Summer is upon us in South Africa and if the experience of the last few years is anything to go by, we are set for scorching temperatures yet again this year. At OG Electrical Services we have seen an upsurge in enquiries and orders for new air-conditioning systems installations, from both our residential and commercial clients.
The most common question we get from our clients is, “what is the best size air conditioner for my house?” Today I have decided to write a blog to help you understand how we get to recommend specific sizes for different set-ups.
In selecting the size of an air conditioner (AC), what is key is to achieve optimal comfort, efficiency, and energy savings. If an AC unit is too small, it will struggle to cool the space effectively. On the other hand, if it’s too large, it will cycle on and off frequently, and just waste energy. It may also not effectively remove humidity from the air.
So, how do you determine the best size for your home? Let’s break it down.
Understand AC Sizing: British Thermal Units (BTUs)
The cooling capacity of an air conditioner is measured in British Thermal Units (BTUs) per hour. The higher the BTU rating, the larger the area an AC unit can cool. However, bigger isn’t always better—oversized units cool rooms too quickly and may lead to temperature inconsistencies and higher energy bills.
General Guidelines for Room Size and BTU Requirements
The table below is a general guide for optimal aircon unit sizes per square meter
| Room Size | Air-Conditioner Size Required |
| 18 sqm | 9 000 BTU |
| 25 sqm | 12 000 BTU |
| 36 sqm | 18 000 BTU |
| 50 sqm | 24 000 BTU |
| 60 sqm | 30 000 BTU |
These numbers are helpful starting points, but several additional factors will affect your exact needs.
Factors to Consider Beyond Room Size
Room Insulation
Well-insulated buildings maintain temperature better, which means you may not need as large an AC unit as a building with poor insulation.
Ceiling Height
Rooms with higher ceilings will require more cooling power because there’s more air volume to cool. If you have 3–4-meter ceilings, consider a slightly larger BTU rating.
Is the room enclosed or has open doorways?
An example of this is a lounge that has open doorways leading to the kitchen, dining room, etc. A room with open spaces will generally require a bigger size aircon.
Sunlight Exposure
Rooms with significant sunlight exposure, especially those with large windows, will generally need more cooling power than rooms that are shaded. A south-facing room in the southern hemisphere, for instance, will require more BTUs.
Climate Zone
Your location’s climate also matters. If you live in a particularly hot and humid region, such as Johannesburg in the summer, you may want to choose a higher BTU capacity to keep up with high temperatures.
While these guidelines can help you estimate, we recommend that you give us a call/WhatsApp us at OG Electrical Services to help you to determine the optimal size for your property. The number to use is +27 73 378 6966 and email info@ogelectrical.co.za
Read more about our air-conditioning services on the following link https://www.ogelectrical.co.za/airconditioners/