The worst time to find out your heating system has a problem is on the first cold night of the year. A little preparation in October or early November can prevent a no-heat emergency in December — and it doesn't take much.
Schedule a Fall Tune-Up
The most important thing you can do is schedule a professional heating tune-up before the cold season. A technician will inspect the heat exchanger (critical for gas furnaces — a cracked heat exchanger can allow carbon monoxide into your home), check the igniter and flame sensor, verify refrigerant levels on heat pumps, clean the system, and confirm everything is operating safely and efficiently.
Fall is the right time to do this — before the cold hits and before technicians are booked solid with emergency calls.
Replace the Air Filter
Start the heating season with a fresh filter. A clean filter ensures proper airflow, which is essential for both efficiency and preventing the high-limit shutoffs that cause furnaces to cycle off prematurely.
If you have a 1-inch filter, plan to replace it every 1–2 months during heavy use. Thicker 4–5 inch media filters can last 6–12 months.
Test the System Before You Need It
Don't wait for the first cold snap to find out your heat works. On a mild fall day, set the thermostat to heat and raise it above room temperature. Let the system run for 10–15 minutes. Listen for unusual noises, check that warm air is coming from the vents, and make sure the system shuts off when it reaches the set temperature.
If anything seems off — unusual smells (especially burning or sulfur), strange noises, or the system not heating properly — call for service while technicians are still available.
Check Carbon Monoxide Detectors
If you have a gas furnace, working carbon monoxide detectors are essential. CO is odorless and colorless — you can't detect it without a detector. Test your detectors and replace batteries. If your detectors are more than 5–7 years old, replace them.
Clear the Area Around the Furnace
Gas furnaces need combustion air and clearance from flammable materials. Make sure nothing is stored within 3 feet of the furnace. Check that the flue pipe (the metal pipe that vents combustion gases outside) is intact and properly connected.
Heat Pump: Check the Outdoor Unit
Clear any debris — leaves, grass clippings, branches — from around the outdoor unit. Make sure the unit has at least 18 inches of clearance on all sides. Check that the unit is level on its pad; settling can cause refrigerant line issues over time.
Don't cover your heat pump in winter. Unlike window AC units, heat pumps need to operate year-round and require airflow.
Frequently Asked Questions
When should I schedule a fall heating tune-up?
September or October is ideal — before the first cold weather and before technicians get busy with emergency calls. Most HVAC companies book up quickly once temperatures drop.
Do I need a tune-up every year?
Annual maintenance is recommended for both furnaces and heat pumps. It keeps the system running efficiently, catches problems early, and is often required to maintain manufacturer warranty coverage.
What does a burning smell mean when I first turn on the heat?
A brief burning smell when you first run the heat after months of inactivity is usually just dust burning off the heat exchanger — it should clear within 15–30 minutes. A persistent burning smell, or one that smells like burning plastic or rubber, warrants a call to a technician.