Why Air Conditioners are Placed at a Height Near Ceiling?

Air conditioners are always installed at the top of the wall. They are put near the ceiling of the room. Ever wonder why air conditioners are placed at a height?

Air conditioners are placed at a height because warm air naturally stays above cold air and the air conditioners need to be able to sense the warm air so that the air conditioners can provide equal and sufficient cooling to the room.

Placing the air conditioner too low can cause insufficient cooling even though the cooling capacity of the air conditioner is enough.

What Height Should Air Conditioners Be Placed At?

Air conditioners should be placed at a height of about 2,100mm to 2,400mm. It is not recommended to install the air conditioner too low on the wall. Otherwise, it will not provide sufficient cooling to the room.

Besides, air conditioners should be installed above our living space. The living space is depending on the average human height in a region. For instance, in Malaysia, most air conditioners are installed at around 2,400mm. As a general rule, we usually place the air conditioner above the door (standard door height is mostly 2,100mm).

Air conditioners are not recommended to install at a level higher than 2,600mm because it will be very difficult for both the installation and service. Typically, most technicians expect a 6-step ladder is sufficient to do the installation or service job. Their maximum reachable height is around 2,800mm with a 6-step ladder. Moreover, cooling the space above 2,000mm is basically a waste of energy.

The Affects of Placing Air Conditioners Too Low

If an air conditioner is placed too low, it can’t sense the correct room temperature and therefore, may not provide equal and sufficient cooling to the room. Because the air at a lower level is colder (since warm air rises), an air conditioner placed too low will get the wrong reading and stop providing cooling despite the room is still warm.

Different types of air conditioner have different temperature sensor location. Below are the common types of air conditioner and their sensor location:

Wall Mounted Air Conditioner

A wall-mounted air conditioner has a temperature sensor inside the indoor unit. The function of the room temperature sensor is to tell the air conditioner what is the current room temperature so that the air conditioner can reduce the compressor’s speed or cut-off the compressor (depending on whether it is an inverter type or not) and therefore, maintain the room temperature as per the temperature setting on the remote controller.

Some wall-mounted air conditioners have a room temperature sensor at the return air section instead. The temperature sensor detects the return air temperature which represents the room temperature and controls the cooling power accordingly.

Window Air Conditioner

The window air conditioner has a temperature sensor at the return air section, behind the filter (just like some wall-mounted air conditioners). A window air conditioner relies on the return air temperature to know what is the current room temperature and therefore, controls the cooling power accordingly.

Floor Standing (Portable) Air Conditioner

Portable air conditioners have a similar setup as the wall-mounted air conditioners. A temperature sensor is usually located at the return air section to sense the current room temperature based on the return air. Some portable air conditioners have a temperature sensor inside the body of the air conditioner to detect its surrounding room temperature.

Why Some Air Conditioners Placed So High?

Commercial buildings usually have some room where the ceiling is very high (doubled). The lobby of hotels, especially 5-star hotels, mostly have a ceiling height of about 6,000mm to 8,000mm because a high ceiling gives off a “grand feel” for the hotels.

However, despite the supply air diffusers are placed so high up, they use jet diffusers which can blast the cold air to the floor level instead of cooling all the space above 2,000mm. If you ever notice, hotels still place their wall-mounted air conditioners at around 2,400mm height even in a high ceiling room.

Does the Position of the Air Conditioner Matter?

Not only the air conditioner should be installed at an optimal height, but it should also be positioned correctly. As a general rule, air conditioners should not blow cold air directly onto the body of a person. It is applicable to both the living room and bedroom. It is especially important for the bedroom due to concerning sleep quality and health issues.

This article was originally published on aircondlounge.com. Actions will be taken for unauthorised republication of this article.

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Yu Chang Zhen

Yu worked as a professional in the HVAC industry for more than 7 years. He is an engineer who has a passion for blogging. Ever since he created this website, Yu has helped hundreds of homeowners and engineers on HVAC related matters.

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