What Rain Does (or Doesn’t Do) to Your AC


There’s nothing quite like getting into bed on a rainy night. The soothing sounds of rain hitting the roof create the best atmosphere for relaxing and sleeping. But you may start to wonder, how does rain affect your air conditioning unit, does it have a negative impact on performance? Is it safe to use your AC while it’s raining?

There are many questions about how the elements can affect your air conditioning unit but it’s not as bad as you may think. Regardless of its make and model, all AC systems are susceptible to the buildup of dust, leaking parts and corrosion. 

However, some may be exposed to the elements more so than others, such as your evaporative unit on the roof or the external unit of a split system. This is when most start to fear whether or not constant exposure will damage their systems. 

Many also seem to believe that turning on the AC unit when it’s raining can cause damage and degrade indoor air quality

To put your fears to rest, let’s take a closer look at what rain really does to your AC, and what it doesn’t do.

What rain doesn’t do to an air conditioner

Rain won’t damage the outdoor unit

Rain will not damage the outdoor unit, even if there is a torrential downpour. The external unit of an AC is made from extremely durable materials which have been designed to withstand harsh conditions, rain, hail or shine.

Rain will not cause rust, unless…

Your unit will not rust from simply getting wet in the rain. The AC system’s metal fins allow air to circulate inside it, drying out any moisture. However, improper covering during the off-season can cause corrosion to certain components. 

Using a makeshift cover such as a garbage bag or plastic cover that does not have ventilation holes can lead to the buildup of condensation and traps moisture. This can lead to leakages, rotting wire, weakened seals, growth of mould and mildew, and corrosion of metal parts. It can also attract unwanted insects and pests.

It’s best to use commercial air conditioning covers which have been professionally designed to keep your AC unit safe and prolong its lifespan.

What rain does to an air conditioner

Rain improves indoor air

Rain doesn’t have a direct effect on your AC unit, but it does improve your indoor air quality. Using air conditioners when it’s raining is a good way to reduce humidity levels, and we all know how humid it can get in Perth. As air moves over the indoor evaporator coil, the moisture is condensed. The PVC tubing then drains it, causing the air to dry when the sun shines again.

Rain helps with performance

Rain helps cool the coils and wash away any dust that has accumulated on it. Clean coils allow for adequate airflow to cool coils down faster, which improves the air conditioners performance and efficiency. 

This is why it is recommended to have your HVAC systems professionally cleaned at least once a month during the peak seasons and at the start of each season, especially commercial systems.

When is your AC system at risk?

1. During a flood

It goes without saying that a flood can cause a substantial amount of damage to property. Heavy rainfall can also submerge a part of the condenser if it’s not protected, which can damage your system. If you have experienced severe flooding it’s highly advisable to have your AC system inspected by a professional before you start it up again. 


2. Storm damage

Heavy rains with powerful winds can carry leaves, twigs, dirt, and other bits of debris into your air conditioning system and damage the condenser fan grille. We recommend giving your outdoor unit a thorough clean after a storm. Lightning strikes and power outages can also cause significant damage to the AC unit, so it’s best to turn off your system to minimise damage caused during a power surge.

How to protect your air conditioning system

  • Power down your system during a storm.
  • Always have your system inspected by a professional after a storm or flood
  • Give your outdoor unit a thorough clean after heavy rains and winds
  • Clean and maintain your ac system once a month during peak seasons and once at the start of every season.
  • Use a commercial air conditioner cover during the off-season

We, at All Air Services, understand that you want to keep your unit in top shape; hence the great concern. We provide air conditioning repairs for a variety of air conditioner brands, so you can count on our reliable technicians to address your AC needs.

For premium cooling and heating services, look no further than All Air Services. Contact us today for an absolute all-year comfort solution.

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