What to Know About HVAC Systems and the Rain


September 20, 2024

With an average annual precipitation of 15 to 23 inches in the areas surrounding Alameda, Santa Clara, Contra Costa, and Sacramento Counties, you may be wondering how rain and HVAC can co-exist when one part of your split heat pump is located on your roof or in your yard. 

Even though the outdoor part of your split heat pump is designed to withstand harsh winter weather conditions like rain and wind, it’s a good idea to understand the benefits and limitations of your split HVAC and the differences between a split heat pump vs. an indoor air conditioner.

At Service Champions, our locally based team of HVAC technicians are well-versed in the effects of California’s rainy season on split heat pumps. We’ll ensure your HVAC is installed in an appropriate location with proper drainage so it can withstand the harsher weather between November and March.

Can Rain Damage My HVAC?

Rain shouldn’t be able to get into the important components of your outdoor heat pump. Because the refrigeration cycle moves hot air outdoors through the exterior unit, its design is such that it can withstand some outdoor wear and inclement weather conditions up to 17°F before losing efficiency. During production, the manufacturer seals electrical components from the rain using sturdy, corrosion-proof materials such as copper, aluminum, and plastics.

That said, you may still experience issues due to weather, such as excessive debris resulting from strong winds, flooding caused by heavy rains, or damage from falling tree branches. The California areas with wet, salty air are also more prone to corrosion on the metal parts. 

How Rain Affects Your Air Conditioner or Heat Pump

Rain damage to your HVAC is rare, but flooding can cause immense water damage to the outdoor components. Humidity and HVACs don’t mix, so it’s a concern if moisture gets trapped inside. 

The best way to ensure your HVAC stays in top condition is to schedule regular maintenance to ward off costly repairs and improve energy efficiency.

Is It Safe to Run My HVAC During a Rainstorm?

In most cases, it’s safe to run your heat and air conditioner in a rainstorm — it's only susceptible to damage in flooding situations. If water starts to partially submerge the unit, the wiring, electronics, and motor could get damaged. Other than extreme situations involving water damage to the HVAC, your outdoor unit is safe to run while it’s storming outside.

What Should I Do If My Outdoor HVAC Unit Gets Flooded?

In the case of HVAC flooding, turn off the unit and the breakers that run power to the system. It’ll need to be professionally serviced to avoid electrical problems, mold growth, and overall performance issues. The CDC recommends a full cleaning of all components to ensure clean air in your home if water gets into your HVAC. 

Protecting Your Outdoor HVAC Unit From Rain Damage

Your outdoor condenser unit is made to withstand moisture and extreme temperatures. Some people choose to cover their units in the winter to protect the HVAC from rain, snow, leaves, and debris, but this can cause more harm than good. Moisture may collect in the cover, resulting in HVAC condensation issues that can lead to corrosion and other damage.

Don’t stack anything on top of the unit, especially when it’s running. It needs proper airflow to perform correctly. If you are worried about something falling and damaging your unit, you may be able to build an awning-type shelter above the unit but speak with a professional HVAC technician first.

HVAC Maintenance in the Rainy Season

HVAC maintenance in the rainy season should involve having an expert give your unit a full tune-up. During an HVAC tune-up, your technician may do the following:

  • Check the thermostat

  • Inspect and tighten electrical connections

  • Look at all moving parts and valves and add lubrication as needed

  • Inspect the condenser coil

  • Check refrigerant 

  • Check and clear the condensate drain

  • Check system controls

  • Change or clean the air filter

  • Test all components thoroughly 

  • And more!

As a general rule, technicians do not service outdoor units in the rain because of the danger involved with working on electrical components in the rain, and by opening the unit up, moisture could cause further damage to your heat pump. If the unit is on the roof, there’s the added risk of falls, lightning, and high winds.

In most cases, a technician will have to wait for the stormy weather to clear before servicing your unit, especially if it’s on the roof. 

Contact Service Champions Today

Service Champions is known for trustworthy, on-time heating and air conditioning service throughout the East Bay, South Bay, and Sacramento areas. Contact us for all your HVAC needs. We’re here to assist you, whether you’re looking to install a new unit or schedule pre-rainy-season maintenance to ensure your HVAC runs perfectly during the wettest months of the year. 

Customers who join our MVP+ Maintenance Value Plan receive an annual tune-up, priority service, special discounts, and guaranteed service times. We also offer helpful financing options so you don’t have to stress over the cost of emergency HVAC repairs or a new system installation. 

If you have any questions or concerns, don’t hesitate to Contact the Champions. Book online, or call us at (833) 600-0991. 

Frequently Asked Questions 

Do I need to cover my AC unit when it rains?

No. Your HVAC is designed to withstand most weather events and doesn’t need to be covered. In fact, covering the unit can cause condensation to form inside, damaging the machinery.

Are there any special maintenance tasks I should do for my HVAC during the rainy season?

A full tune-up by an HVAC technician is the best way to ensure your system runs in top condition before the rains begin. As a homeowner, ensure all filters are changed, your drain pipes are clear, and the outside of the condenser coils is free of leaves, grime, and debris.

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