What is the difference between inverter and fixed-speed AC? Choosing a unit is not just about the name

“Inverter” describes how the compressor output is controlled, not a separate body type for window or split units. Both window and split units may have inverter models; compare the model type, cooling capacity and control method separately when choosing a unit, instead of deciding by name alone.

What is the difference between speed control and start-stop control?

A conventional fixed-speed air conditioner controls cooling by switching the compressor on and off. An inverter model can adjust the compressor speed within its design range to change output according to the room load. As the temperature approaches the target, inverter control can reduce output to minimise temperature fluctuations, but it does not mean the unit never stops in any environment, nor does it mean the fan will never change airflow.

What usage scenarios are worth comparing?

For rooms used continuously or where a more stable room temperature is desired, inverter models can be included in the comparison. For rooms used only for short periods, make the choice based on the actual model and budget. Sunlight, doors and windows, number of people, and settings all affect the load, so you cannot assume a brand's energy-saving claim under specific test conditions will necessarily be the same at home.

The Consumer Council's tests show that inverter models with the same Grade 1 label can still differ in energy efficiency. Therefore, "inverter" does not mean the same level of energy saving. This article does not provide a fixed electricity-saving percentage or payback period.

Specification comparisons should be made on the same basis

• Compare the rated cooling capacity, rather than just the common labels of one or one-and-a-half horsepower
• Check the energy rating, CSPF and the comparison basis for the stated annual power consumption
• Check both indoor and outdoor noise at the same time, and note the fan speed and mode used
• Confirm whether the unit price includes removal of the old unit, installation, extra piping and other works

Are inverter repairs always more expensive?

You cannot quote a fixed repair price based only on the control method. The fault scope, availability and work conditions for the control board, compressor, sensors and other parts all differ. Manufacturer warranty also depends on the written terms for that model; it cannot be summed up as covering everything or covering nothing. Whether an existing unit is worth repairing can be seen fromRepair or replacement comparison。

How should you prepare before replacement?

First list the room use, usual operating hours, indoor and outdoor locations, then choose candidate models with similar capacity and compare the total cost and specifications. Can be arranged withHorsepower and cooling capacity factors、How to read the energy labelandInstallation quotation scopeDo not compare the price of a new unit directly with the cost of a one-time repair.