As winter fades and temperatures begin to rise in Herrin, IL, it's time to think about switching your HVAC system from heating mode to cooling mode. That change may seem as simple as adjusting the thermostat, but a safe and effective transition requires a few important checks first. Inspecting and preparing your equipment can help you avoid early-season breakdowns. You may be able to save on energy costs, too.

Start by Checking Your Thermostat Settings

Your thermostat controls how your HVAC system operates, so it should always be the first place to look when transitioning from heating to cooling. Many thermostats remain set to Heat after winter, preventing the air conditioner from activating even when indoor temperatures rise.

Switch the thermostat mode from Heat to Cool, and confirm that the temperature setting is below the current room temperature. This change allows the air conditioner to run normally again. If the thermostat runs on batteries, replace them before the cooling season begins. Fresh batteries ensure accurate temperature readings and prevent sudden system shutdowns later.

Smart thermostats may also require seasonal schedule adjustments. Many homeowners reduce heating schedules during the winter months and forget to update them for the cooling season. Reviewing the programming ensures your system cools the home efficiently during warmer weather.

Replace the Air Filter Before Running the AC

Your HVAC system likely ran frequently throughout the winter, so the air filter has collected dust, debris, and airborne particles. A clogged filter restricts airflow and forces the air conditioner to work harder once the cooling season begins.

Remove the current filter, and check its condition. If the filter appears dirty or gray, replace it with a clean one. Proper airflow allows the system to move cooled air throughout the home without strain. A clean filter also protects important components such as the evaporator coil from dust buildup. Changing the filter before switching to cooling mode also improves indoor air quality. When the AC begins circulating air again, it will move cleaner air throughout the home.

Inspect the Outdoor Condenser Unit

Your outdoor condenser unit sits idle throughout the winter months, allowing leaves, dirt, and debris to accumulate around it. Before starting the cooling system, inspect the area around the condenser and clear away anything that could restrict airflow. Remove branches, leaves, or dirt that may have collected near the unit. Trim nearby plants so they do not block airflow. Your condenser needs open space to release heat effectively, so maintaining at least 2 feet of clearance around it helps the system to operate efficiently.

Next, inspect the condenser fins for dirt buildup. If dust or debris covers the coil surface, gently rinse the unit with a garden hose to remove loose debris. Don't use high-pressure water that could bend the delicate fins.

Check the Condensate Drain Line

Air conditioners remove humidity from indoor air as they cool the home. This moisture travels through a condensate drain line that carries water away from the system. Over time, algae or debris can clog this drain line and cause water to back up into the system.

Locate the drain line near the indoor air handler, and check for signs of blockage. If water appears around the base of the unit, the drain line may require cleaning. Pouring a small amount of white vinegar into the line can help prevent algae buildup and keep the drain flowing properly. A clear condensate line prevents water damage and helps maintain proper humidity control during the air conditioning season.

Test the System Before Hot Weather Arrives

Many homeowners wait until the first hot day of the year to turn on their air conditioner. That moment is one of the worst times to reveal hidden problems that developed during the off-season. Testing the system early allows you to identify issues before the summer heat places a heavy demand on the equipment.

After completing the basic inspections, turn the thermostat to Cool, and allow the system to run for about 15 minutes. During this test period, listen for unusual sounds such as rattling, grinding, or buzzing. Air should flow steadily from the vents and gradually begin cooling the home. If the system struggles to produce cool air or shuts off quickly, a professional inspection may be necessary. Addressing these concerns early can prevent larger failures later in the season.

Inspect Indoor Vents and Airflow

Proper airflow plays a major role in cooling performance. During winter, homeowners sometimes close vents in unused rooms or move furniture to block airflow near registers. These adjustments can create airflow imbalances once the cooling season begins.

Walk through the home and check that all vents remain open and unobstructed. Remove furniture, rugs, or curtains that may be blocking airflow from supply vents or return registers. Balanced airflow allows the system to distribute cooled air evenly throughout the home. If certain rooms feel warmer than others, the issue may relate to airflow restrictions or duct problems. Identifying these concerns early helps maintain consistent comfort across your entire home.

Listen for Unusual Noises When the System Starts

Your HVAC system may produce brief startup noises when switching from heating to cooling mode. However, loud or persistent sounds often signal developing mechanical problems. Pay attention to unusual noises during the first few cooling cycles of the season. Grinding sounds may indicate motor issues, while rattling could point to loose components. A buzzing sound may signal an electrical problem within the condenser unit. If these noises continue, turn off the system, and schedule professional service with us at One Hour Heating & Air Conditioning®.

Schedule a Professional AC Tune-Up

Our team of HVAC technicians will evaluate your air conditioner for refrigerant levels, electrical connections, blower motors, and system controls. We will also clean the evaporator and condenser coils to improve heat transfer and energy efficiency. With professional maintenance, the system can operate safely and reliably when summer arrives. Regular tune-ups also help extend the lifespan of your air conditioner.

Don't Lower the Thermostat Too Quickly

When you first switch your system from heating to cooling, you may immediately lower the thermostat to a much cooler setting. This sudden change forces the system to run continuously in an attempt to reach the new temperature. Instead, allow the home to cool gradually. Setting the thermostat only a few degrees below the current temperature allows the system to stabilize and prevents unnecessary strain on the compressor. Gradual adjustments also help to maintain consistent indoor humidity levels, improving your comfort during warmer months.

Schedule Seasonal Service Today

Transitioning your HVAC system from heating to cooling mode marks an important seasonal shift for your home. With proper preparation and professional maintenance from One Hour Heating & Air Conditioning®, your air conditioner can deliver reliable comfort throughout the warmer months. Our team can help you prepare your systems.

You can rely on us because we have decades of combined experience providing heating and cooling services to the Herrin area. Call One Hour Heating & Air Conditioning® today to schedule your next HVAC service.