Does the Set Temperature Equal the Actual Indoor Temperature?

Many people have the experience when using the air conditioner that we set a temperature at 26℃, but the room temperature is still not comfortable. Is that the error of the sensor or the air conditioner itself?

The answer is that when the air conditioner is set to a temperature, it does not mean the temperature at every corner of the room. We are going to explain it clearly based on its mechanism.

I. What exactly does the "set temperature" of an air conditioner measure?

The air conditioner does not measure the whole room temperature, but it determines whether it needs continuous cool or heat by the sensor.

In most of the wall mounted air conditioners or floor standing air conditioners, the temperature sensor is normally located near the air inlet of the indoor unit or inside the air inlet zone, which measures the air temperature near the air conditioner. This means that whether the air is conditioned to 26℃ or not depends not on the position where you are but on the area around the air conditioner.

II. Why are there different temperatures in the same room at the same time?

The temperature is not completely uniform even in the same room. There are factors that influence it: 

1. Air stratification

The cold air has high density, which tends to sink, while the hot air has a low density and tends to rise. As a result, the space that is close to the ground is colder, and the space that is close to the ceiling is hotter. That's why some feel cold on the feet and hot on the head and feel uncomfortable. With an air conditioner operating, people still feel uncomfortable.

2. Building structure and insulation conditions

West-facing walls, glass windows → continuous heat taken in

Wide room space, high floor height → stronger thermal inertia

Leakage in door gaps and window gaps → Continuous coolness loss

All these will mislead the air conditioner to regard the cooling procedure as having reached the setting temperature, but the whole room is not truly stable.

3. The relation between airflow and the human body position

Direct air blow → More cooling;

Back-wind zone or corners → Higher temperature;

At the same 26℃, people sitting beneath the air outlet will feel cold, while those sitting at the corner will feel hot.

III. Why is 26°C sometimes still cold?

This is a common misconception among many people. Actually, the air conditioner is working between a temperature range instead of pursuing 26℃.

For example, the setting temperature is 26℃, but the actual control range is 25℃ to 27℃. When the sensor detects the temperature lower than the limit (here 25℃), the compressor will slow its speed or stop working; when higher than the limit (here 27℃), the compressor will start to work again.

If at this time, you sit near the direct air blow area or around the sensor, you will feel colder but with a not-so-low temperature setting.

IV. Why do the inverter air conditioners seem more stable?

Compared with normal non-inverter air conditioners, the advantages of the inverter air conditioners lie in the following facts:

· The compressor speed is continuously adjustable;

· The temperature fluctuation is lower;

· The indoor airflow is more smooth and comfortable;

This doesn't mean the inverter air conditioners measure the temperature more precisely, but when the air reaches the setting temperature, it works at a low power continuously instead of stopping working. Finally the indoor temperature becomes more uniform, and the experience of the human body is more comfortable.

V. How to adjust the room temperature more reasonably?

Instead of struggling over whether the temperature is precisely measured or not, we'd better focus on the comfort and the power consumption.

Common advice:

· Summer cooling temperature: 26-28℃;

· Adopt with wind speed adjustment instead of lowering the temperature blindly;

· Avoid long-time direct air blow;

· Slightly close the window, curtains, and doors when there is poor tightness in the room;

Noted: The air conditioner is to remove excessive heat, not to "create low temperature".