It’s Cottonwood Fluff Season! Time to Clean Your HVAC Coils.

In Southern Oregon, the arrival of spring signals warmer weather, blooming flowers, and, for commercial property managers, the perfect time to schedule HVAC maintenance. But one seasonal phenomenon often catches businesses off guard: cottonwood fluff. That airy white fluff floating through the air is more than just a visual nuisance—it’s a significant cause of cottonwood clogging HVAC systems, especially rooftop units.

At Stone Heating and Air, we understand how Southern Oregon’s natural environment directly affects your heating and cooling systems. Here’s a brief look at how cottonwood trees contribute to HVAC issues, when cottonwood fluff is most prevalent, and why proactive spring maintenance is essential for keeping your commercial systems running efficiently.

What Are Cottonwood Trees?

Cottonwood trees (genus Populus) are fast-growing, deciduous trees commonly found throughout the Pacific Northwest, including many parts of Southern Oregon. Two notable species in the region include:

• Black Cottonwood (Populus trichocarpa) – Native to the Pacific Northwest, often found near rivers and streams.
• Fremont Cottonwood (Populus fremontii) – More common in southern parts of the state and arid environments.

These trees thrive in riparian zones—areas close to water sources such as the Rogue River, Bear Creek, and Applegate River. Their adaptability and rapid growth make them widespread across Jackson, Josephine, and Klamath counties.

Cottonwood trees release their seeds encased in fluffy white fibers between mid-May and early June. This brief yet intense period—sometimes called “cottonwood snow”—can result in thick layers of cotton-like fluff accumulating on rooftops, sidewalks, and air intakes. While the visual effect may resemble falling snow, the consequences for commercial HVAC systems are far from pretty. Cottonwood fluff is notorious for clogging HVAC coils, filters, and screens, reducing airflow and efficiency when your cooling system is needed most.

Why Cottonwood Fluff Is a Problem for HVAC Systems

1. Restricted Airflow and Overheating

When cottonwood fluff builds up on condenser coils, it forms a barrier that blocks the free exchange of heat. As a result, your HVAC system has to work harder to cool your building, which can lead to:

• Increased energy consumption
• Overheating compressors
• Short cycling or system shutdowns

2. Reduced Cooling Efficiency

The more debris builds up, the less efficient your unit becomes. A clogged coil reduces heat transfer and compromises the system’s ability to maintain comfortable indoor temperatures, especially critical in commercial spaces with high foot traffic or equipment.

3. Higher Operating Costs

The strain on your system impacts performance and increases energy costs. Depending on how severely it’s affected, a commercial HVAC unit battling cottonwood blockage could consume 10–30% more electricity.

4. Premature Equipment Failure

Cottonwood buildup can shorten the lifespan of critical HVAC components such as fans, compressors, and motors without proper cleaning and maintenance. Over time, this results in higher repair bills or early replacement.

Preventative Measures to Protect Against Cottonwood Clogging HVAC Systems

Timing is everything when it comes to maintaining commercial HVAC systems in Southern Oregon. Scheduling coil cleaning just before or during the peak of cottonwood fluff season helps prevent the most severe buildup and ensures your system is ready for summer.

At Stone Heating and Air, our technicians perform a thorough cleaning of:

• Condenser coils (typically the most impacted)
• Air filters and screens
• Fan blades and motor housings
• Surrounding debris on rooftops or near units

We also check refrigerant levels, test electrical components, and assess the overall system for signs of wear and tear caused by the colder months.

Beyond cleaning, there are several steps businesses can take to reduce the risk of cottonwood damage:

➤ Install Cottonwood Screens

These mesh screens are specially designed to fit over outdoor coils and prevent seed fluff from reaching the surface. They are easy to remove, clean, and reinstall.

➤ Increase Filter Replacement Frequency

If your building’s ventilation pulls in outside air, change your filters more frequently during May and June to prevent fluff buildup on internal components.

➤ Trim Nearby Trees

If cottonwood trees are located directly on your property, trimming branches away from buildings and HVAC units can reduce the direct impact of seed fallout.

➤ Add a Maintenance Visit in Late Spring

For facilities near rivers or wooded areas, adding a short mid-spring maintenance visit to your annual service schedule can save money and headaches later in the summer.

Stone Heating and Air will Protect Your HVAC from Cottonwood Fluff.

Don’t let cottonwood clogging HVAC systems become your business’s first sign that spring has arrived. By understanding when and why cottonwood fluff causes problems, and scheduling coil cleaning accordingly, you can avoid costly repairs and keep your building cool and comfortable throughout the summer.

As a locally owned and operated HVAC company based in Southern Oregon, Stone Heating and Air understands the specific challenges posed by our region’s climate and vegetation. We don’t just service HVAC units—we provide tailored solutions based on local conditions and decades of experience.

Our commercial HVAC coil cleaning services are designed to:

• Improve energy efficiency
• Extend the life of your equipment
• Minimize system downtime
• Provide peace of mind as summer temperatures rise

Whether your business is in Medford, Central Point, Grants Pass, Ashland, or the surrounding area, we’ll work with you to create a maintenance plan that protects your investment year-round.

Stone Heating and Air is here to help Southern Oregon businesses stay ahead of seasonal HVAC challenges. Contact us today to schedule your spring HVAC maintenance and safeguard your rooftop units before the cottonwood starts to fly. Visit www.stoneheatair.com to request a commercial coil cleaning appointment today!