Do I Need A Power on Delay For My Aircon?

Brownouts are so common in the Philippines that we’ve pretty much gotten used to its annoyance. However, did you know that once the power comes back on, it can do severe damage to your aircon? This is what the little nifty device called the Power on Delay is designed to mitigate.

A Power on Delay is a device that protects your aircon from the effects of voltage fluctuations after a brownout.

In this article, we will explain how a brownout will affect your aircon, and why you should buy a Power on Delay for it.

Note: in other countries, low voltage fluctuations are usually known as “brownouts”. However, in the Philippines, brownouts and blackouts/power outages have the same meaning.

What is a power on delay?

power on delay for appliance

As said earlier, the Power on Delay is a device that protects your aircon from the effects of voltage fluctuations after a brownout.

After a power outage, it delays the incoming electrical current for 3-5 minutes to ensure that the power stabilizes before it reaches the aircon. This protects your aircon from the expected voltage surge after the power outage.

Why should you buy a power on delay for your aircon?

Brownouts are quite common in the Philippines. However, they are not just a mild annoyance – it can cause severe damage to your aircon if you do not protect it with a power on delay.

How does a brownout affect your aircon

A power outage (otherwise known as blackout or brownout) is a loss of electric power in a given area that can last for minutes or for days.

All appliances stop working during a brownout. However, the damage to your appliances doesn’t occur when the power goes out, but when the power goes back on line.

The energy that comes immediately after a brownout can be unstable; the voltage might be too high or too low. When the voltage is too high, it can cause a power surge; too low, then a power sag will occur. Both are bad news for your aircon.

What is a power surge

Power surge

A power surge is a short-duration (3 nanoseconds) oversupply of voltage that increases the voltage significantly above the standard level.

Power surges can not only destroy your air conditioner, it can also start an electrical fire. A strong power surge can cause an arcing of electrical current in your aircon. This produces heat and can make your air conditioner’s parts to overheat.

Air conditioners with microprocessors and inverter boards are especially susceptible to damage as strong power surges can fry these parts and even melt some of the plastic parts away. While weak power surges have a low chance of destroying your aircon outright, it can build incremental damage to it, affecting its performance and shortening its lifespan overtime.

What is a power sag/low voltage fluctuation

A low voltage fluctuation decreases the voltage significantly below the standard level. Not all appliances gets damaged by low voltage fluctuations. However, appliances with motors (like an aircon’s compressor) are especially susceptible.

Your air conditioner’s compressor needs to maintain a level of torque to work. A higher voltage will increase torque, while a reduced voltage will reduce torque. If the torque decreases to a certain level, it will stall your compressor. However, power will still be supplied to the it, hence the compressor will produce heat even though its not working.

If this heat continues to build up, it can melt the insulation wires and other parts of your aircon, making it less efficient in the long run. It can also totally destroy your compressor and the whole aircon itself or start a fire if you do not invest in a low voltage protection device.

What are the benefits of having a Power on Delay for your aircon

Aside from protecting your aircon from the effects of a brownout, a Power on Delay gives you the following benefits:

1. Allows the air conditioner’s refrigerant gases to stabilize first

An aircon works by constantly circulating a refrigerant gas throughout its evaporator and condenser coils with its compressor.

When the compressor stops working, the refrigerant needs to stabilize first before it can be safely turned on again. If you did not give it time to stabilize, it can cause issues with improper cooling.

Since the Power on Delay gives you 3-5 minutes of time before it turns the aircon back on, it gives time for the refrigerant gas to stabilize.

2. No need to unplug and plug-in your aircon during and after a brownout

With a Power on Delay, there will be no more need to manually unplug your aircon when a brownout happens, then plugging it back in a few minutes after the electricity comes in. It all happens automatically!

3. Some Power on Delay models have a built-in voltage protector as well

While a Power on delay does offer some protection against brownouts, the coverage is a little limited. Remember: it does not do anything to protect your aircon DURING the brownout; it only kicks in AFTER the brownout is over.

To add more protection, some models of Power on Delay have a built-in voltage protector to protect your aircon from power surges and low voltage fluctuations as well.


Air conditioners are expensive upfront but will last you decades if you take care of it right. I highly recommend that you should invest in power protection equipment such a Power on Delay to protect your investment and to prolong the usable life of your aircon.

1 thought on “Do I Need A Power on Delay For My Aircon?”

  1. 1. Sir, thank you for your informative article. What AVR or power surge protector do you recommend for a non-inverter split aircon with the following specifications?
    2,150 WATTS
    What should the rating (Wattage) of the AVR be?

    2. The aircon model is Daikin:

    Thank you.


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