5 Reasons Your Heater Is Alternating Between Blowing Hot and Cold Air & How to Fix It!

Your home can quickly become uncomfortable when the heater is alternating between hot and cold air, especially during the winter months. On top of that, a malfunctioning heating system can also lead to higher energy bills and unnecessary wear on HVAC components. While this issue is frustrating, the experts at Russell Heating & Air are here to help you diagnose and fix the problem quickly. Let’s take a look at five common reasons why your heater is alternating between blowing hot and cold air & how you can resolve it.

Common Causes: Heater Alternating Between Blowing Hot and Cold Air

1. Thermostat Issues: Most Common Reason for Heater Alternating Between Blowing Hot & Cold Air

Your thermostat controls the temperature and signals your heating system when to turn on and off. If it’s faulty, improperly set, or has low batteries, it may cause the heater to alternate between blowing hot and cold air.

How to Fix It:

• Check your thermostat settings and ensure it’s set to “heat.”
• Replace the batteries if they are low.
• Clean the thermostat’s sensors to ensure proper temperature readings.
• If problems persist, consider upgrading to a programmable or smart thermostat for better control and energy efficiency.
• Ensure the thermostat is installed in a central location, away from drafts or direct sunlight, to prevent inaccurate readings.
• Smart thermostats may require recalibration.

2. Clogged Air Filters: Second Most Common Reason for Heater Alternating Between Blowing Hot & Cold Air

A dirty air filter restricts airflow, which can cause your heating system to overheat. When this happens, the system shuts off the heat temporarily, leading to inconsistent temperatures. Over time, this can also cause strain on your HVAC system, reducing its lifespan and efficiency.

How to Fix It:

• Inspect your air filter and replace it if it appears dirty.
• Change filters every 1-3 months to maintain proper airflow and system efficiency.
• Consider using high-efficiency filters to enhance indoor air quality and reduce allergens.
• Schedule routine HVAC maintenance to ensure airflow remains unobstructed.

3. Malfunctioning Flame Sensor

The flame sensor is a crucial component that detects whether the burner is ignited. If it’s dirty or faulty, it may shut off the burner intermittently, causing the heater to alternate between blowing hot and cold air. This safety feature prevents unburned gas from being released into your home but can cause heating disruptions if not functioning correctly.

How to Fix It:

• Turn off the power to your heater before performing maintenance.
• Clean the flame sensor using a soft cloth or fine sandpaper to remove buildup.
• If cleaning doesn’t work, call Russell Heating & Air for a professional replacement.
• Regularly schedule HVAC inspections to ensure all safety components function properly.

4. Ductwork Issues

Leaky or poorly insulated ductwork can cause uneven heating. As warm air escapes, some rooms may feel warm while others feel cold. Inconsistent ductwork insulation can also cause heat loss, making your HVAC system work harder than necessary.

How to Fix It:

• Inspect visible ductwork for gaps, holes, or loose connections.
• Seal leaks with duct tape or mastic sealant to prevent heat loss.
• Confirm that all ductwork is properly insulated, especially in unheated areas like attics or crawl spaces.
• Schedule a professional duct inspection for a thorough assessment and proper sealing.
• Remove dust and debris in the ductwork that may obstruct airflow.

5. Failing HVAC Components: Least Common Reason for Heater Alternating Between Blowing Hot & Cold Air

If your heating system is aging or has worn-out parts, it may struggle to maintain a consistent temperature. Components such as the blower motor, heat exchanger, or control board could be failing, leading to inefficient performance.

How to Fix It:

• Listen for unusual noises, which could indicate mechanical failure, such as rattling or squealing sounds.
• Schedule an inspection with a certified HVAC technician to diagnose and repair faulty components.
• Consider replacing an old unit with a more energy-efficient model to improve performance and reduce energy bills.
• Ensure routine maintenance is performed to extend the lifespan of your heating system.

Heater Is Alternating Between Blowing Hot and Cold Air: When to Call a Professional

If you’ve tried these fixes and your heater continues alternating between blowing hot and cold air, it’s time to seek professional help. The experts at Russell Heating & Air can diagnose the issue and restore comfort to your home. We offer expert HVAC inspections, repairs, and installations to keep your heating system running efficiently.

Contact Russell Heating & Air in Canton, GA, to ensure your home stays comfortable all year long!