When the weather starts to change, many homeowners ask how to safely switch from AC to heat without causing problems for their HVAC system. As someone who works on heating and cooling systems every day, I can tell you that making this transition the right way can prevent breakdowns and save you money.
Let’s look at the simple steps you can take to switch from AC to heat, what to check before you do it, and how to keep your system running smoothly all season.
Why Switching from AC to Heat Matters
Your HVAC system has worked hard all summer to keep your home cool. When you go from AC to heat, you’re asking it to do the opposite job. Making that switch correctly keeps your system efficient and helps avoid unnecessary wear and tear.
According to the U.S. Department of Energy, even small thermostat changes can affect your comfort and your energy bill. That’s why it’s important to switch modes correctly and at the right time.
Step 1: Turn Off the AC Before Switching
Before changing from AC to heat, turn your system completely off. Give it a few minutes to stop running. This protects your compressor and allows the refrigerant pressures to balance out. Skipping this step can cause your system to short cycle or make strange noises when you switch modes.
Step 2: Adjust the Thermostat Setting
Once the system is off, set the thermostat to “HEAT.” Then choose a temperature a few degrees higher than the current room temperature so the system actually cycles on. If you have a programmable or smart thermostat, this is a great time to update your schedule for fall and winter.
Step 3: Listen and Check for Warm Air
After you switch from AC to heat, wait for warm air to start coming from your vents. It might take a minute or two. If you still feel cool air after several minutes, check your filter and thermostat settings again.
Step 4: Replace or Clean Filters
Transitioning from AC to heat is the perfect reminder to check your air filters. Dirty filters can cause your furnace to overheat and shut down or your heat pump to work harder than it should. Replace filters every 30–90 days for best performance.
Step 5: Inspect Your Outdoor Unit
If you have a heat pump, look over the outdoor unit to make sure it’s clear of debris and leaves. A blocked unit can’t move air properly, which means your system may struggle to heat efficiently.
Seasonal Maintenance Before Switching from AC to Heat
Scheduling professional heating maintenance is one of the best ways to make sure your system is ready to go from AC to heat without issues. During a fall tune-up, a technician will:
Inspect and clean burners and heat exchangers
Test safety controls
Check refrigerant levels for heat pump systems
Verify thermostat calibration
Ensure airflow is balanced
For efficiency guidance year-round, see ENERGY STAR’s Heat & Cool Efficiently tips, which include best practices for filter changes, duct sealing, and equipment maintenance.
Troubleshooting Common Problems
Even when you follow all the steps, you might run into issues when switching from AC to heat:
Cool air from vents: Check the thermostat mode, replace the filter, and make sure the outdoor unit is running.
Burning smell: A mild dusty smell is normal the first time you run heat each season, but strong odors may indicate an electrical issue.
Unusual noises: Loud bangs or squeals should be checked by a professional.
If you notice any of these problems, it’s safest to turn the system off and call a technician for heating repair.
Contact Summers Comfort Heating & Air
Don’t wait until the first cold snap leaves you with a chilly house. Contact Summers Comfort Heating & Air today to schedule your seasonal tune-up or repair service. Our technicians will make sure your system is ready to handle the switch from AC to heat without any surprises.
Final Thoughts: AC to Heat
Switching from AC to heat doesn’t have to be stressful. By turning off the system first, adjusting your thermostat properly, checking your filters, and scheduling maintenance, you can make a smooth transition into the heating season. And if something doesn’t seem right, don’t hesitate to call a professional. With a little preparation, you’ll enjoy steady, efficient heat all winter long — and fewer worries about mid-season breakdowns.
If you’re in Denham Springs, Baton Rouge, or one of the surrounding areas, Summers Comfort Heating & Air is here to help you stay comfortable all season.
