How to Prepare Your Furnace for Fall and Winter

Modern HVAC September 5, 2025 0 Comment

The colder months are just around the corner, which means that its a good time to check your furnace, and schedule an annual tune-up with your local HVAC company.

Below are some steps we suggest taking for ensuring that your furnace is ready for fall and winter:

8 Steps for Preparing Your Furnace for the Colder Months

1. Make Sure Your Furnace Filter is Clean

To start, our team suggests that you begin your fall preparation by inspecting and replacing your furnace filter. A dirty filter restricts airflow, forcing your system to work harder and reducing efficiency. Check the filter monthly during heating season and replace it every 1-3 months depending on usage and filter type.

If you’re unsure of whether the filter is dirty, try holding it up to light – if you can’t see through it clearly, it’s time for a replacement. Clean filters improve air quality, reduce energy costs, and extend your furnace’s lifespan.

If you have pets or someone with asthma living in your home, you will need to change out the furnace filter more frequently, approximately once every month or so. We cover more about how often you should change your HVAC filters in our article here.

2. Run Your Heat To Make Sure It’s Running

Another tip we have for preparing your furnace for fall and winter is to perform a heat test.

A heat test is a pretty simple task to perform to ensure that your furnace is working properly. This test entails turning up your thermostat about 10-15 degrees above the current room temperature.

You’ll want to listen for the system to start up. Within 10-15 minutes of starting the furnace, you should start feeling warm air coming through the vents throughout your house. This test run helps you identify any issues while you still have time before fall and winter.

In the case that the system doesn’t start, produces poor levels of heat, or shuts on and off unexpectedly, you should contact your local HVAC company as soon as you can to troubleshoot the issue.

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3. Check for Any Strange Noises or Odors

An important part of preparing your furnace for fall and winter is checking for any strange sounds. During your test run, you should pay attention to unusual sounds like grinding, squealing, banging, or rattling that weren’t present before.

You should also note any strange odors – for example, while a slight dusty smell is normal after months of non-use, any gas odors, burning smells, or persistent musty odors will require attention from a furnace professional.

Be sure to make a note of any concerning sounds or smells to report to your technician as this will help us diagnose the issue.

4. Change Your Thermostat Batteries or Reprogram Your Thermostat

Next, we recommend changing out your thermostat batteries. This is one of the most simple steps you can follow to prevent unexpected failures during cold weather. Even if your thermostat seems to be working fine, old batteries can make your thermostat function erratically or even completely shut down your system.

If you have a programmable thermostat, your should review its manual and update your heating schedule to match your fall and winter routine mentioned in the documentation. Try programming lower temperatures when you’re away or sleeping to maximize energy savings.

If you have questions about your thermostat settings, we’re here to help! Just give us a call at (920) 733-4713.

5. Clean & Seal the Air Ducts

The next step of preparing your furnace for fall and winter is to clean and seal the air ducts in your heating system.

You should inspect any visible ductwork for dust buildup, loose connections, or air leaks around the joints and seams. Also, we suggest using a vacuum with a brush attachment to clean any dust or debris from the accessible duct surfaces and vents.

For sealing, you should seal any gaps or loose connections with metal tape or mastic sealant, but don’t use standard duct tape since that tends to deteriorate over time.

If needed, our HVAC technicians can provide this service for you during our annual furnace tune-up appointment.

6. Clear the Furnace Flue

In the case of gas furnaces, you should check the flue pipe and chimney to make sure they are both clear of bird nests, leaves, or debris that may have accumulated during the off-season.

Also, check that the flue cap is secure and undamaged. A blocked flue can cause dangerous carbon monoxide buildup inside your home.

If you’re uncomfortable checking the flue yourself or notice any damage, have a professional from Modern Sheet Metal inspect and clean it to ensure safe operation during the winter.

7. Perform a DIY Maintenance & Safety Check

If you are comfortable with performing a DIY maintenance check yourself, here are a few of our suggestions to help prepare your furnace for fall and winter:

First, inspect the area around your furnace to make sure that it’s clean and free from any stored items, especially flammable materials.
Check that all access panels are secure and properly installed.
It’s important that your carbon monoxide detectors are working, so be sure to replace the batteries if needed.
Next, check for any signs of visible gas connections, corrosion, or damage, and make sure that electrical connections appear secure.
Lastly, look for any signs of water leaks, rust, or unusual wear on the unit itself.

We detail more information about performing a DIY maintenance check on your HVAC system in our heating and cooling guide linked here.

8. Contact Your HVAC Professional for an Annual Tune-Up

The last step we suggest for preparing your furnace for fall and winter is to schedule a professional furnace inspection and tune-up before heating season begins in the fall. A qualified technician will perform a thorough check that goes beyond DIY maintenance. This includes testing safety controls, measuring gas pressure, inspecting heat exchangers, lubricating moving parts, and calibrating the system for the best performance possible.

An annual furnace maintenance service can prevent expensive breakdowns, improve the system’s efficiency, extend equipment life, and ensure your family’s safety throughout Wisconsin’s colder months.

Schedule a Furnace Tune-Up with Modern HVAC!

We are the furnace experts! With more than 60 years of professional industry experience serving customers throughout Appleton, Neenah, Menasha, Kimberly, Greenville, and Darboy, we provide HVAC solutions that you can rely on. Our Carrier-certified technicians offer FREE estimates and second opinions to help prepare your furnace for the fall and winter months.

Whether you are looking for a brand new gas or electric furnace installation, have a furnace repair, or you just need a tune-up, we’ve got you covered! Our complete heating and cooling services for furnaces include installations/replacements, repairs, maintenance, and emergency services.

To get started, please contact Modern HVAC today by phone at (920) 733-4713 or by contacting us online.