Q: Does Rain Harm My Central Air Unit?

A frequent question we hear from our customers is whether the rain and other inclement weather can harm their central air unit. It’s a great question, because the compressor unit likely sits somewhere alongside or near your house, and, given your investment, it’s understandable to ask about exposure issues.

The Compressor

According to Rheem:

“The compressor plays an integral role in cooling your home. It is the device responsible for pumping refrigerant through the refrigerant lines and the coil, making the transfer of heat from inside your house to the outdoors possible.”

And, it’s built to last, even under the harshest conditions, including rain, snow and hail.

“Rheem compressors, and central air compressors generally, are designed to operate safely in the rain,” according to Iron Fireman President Patrick Lammert. “In fact, running your A/C during a storm helps remove humid, uncomfortable air from your house, so definitely turn it on.”

Preventative Maintenance

However, homeowners still have to keep an eye on it. To keep your unit in optimum condition, be sure to:

  1. Never put anything on top of the unit.
    A rolled up garden house, for example, can block the flow of air to the fan.
  2. Make sure that the your outdoor condenser coils are clean.
    If they’re dirty with grease and grime, you should turn off the unit and clean them with a heavy-duty de-greasing agent and wash them clean with a garden hose.
  3. Prune your bushes and foliage.
    Iron Fireman recommends that your shrubs and plants should be 18 inches away from each side of your central air unit.
  4. Direct your lawn mower away from the unit when cutting the grass.
    Grass cuttings and other debris results in dirty or obstructed coils that can drastically reduce the efficiency of your central air system.
  5. Exercise care in using a weed whacker around the unit.
    Just like grass cuttings from your mower, weed whackers generate lawn waste that can dirty your coils. Even more important is not allowing your weed whacker to touch the unit itself, because the line can flatten the aluminum fins, or cut the units thermostat wires, which can short out the transformer. If that happens, its a very expensive repair.


While the compressor can withstand heavy rain, it’s not built to withstand floods. That’s why professional installers often place the compressor on a concrete slab, which prevents the unit from being submerged by flood waters. In the event the unit is submerged, its nternal components will be damaged beyond repair.

What about In Winter?

In our experience, Rheem air conditioners are built to withstand even the coldest Wisconsin winter. A good rule of thumb, though, is to remove any snow built up on the top, so the weight doesn’t crush the cage above the fan, or the fan itself.

Homeowners who wish to cover their units should only use covers recommended by the manufacturer. Stay away from waterproof tarpaulin or other plastic tarps, because they prevent air from entering into the unit to dry its internal components.

Questions? We're Here to Help!

If you have any questions about any topics discussed on our blog, Iron Fireman is here to help! Just visit our contact page to send us an e-mail or call us at (262) 646-4505.

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