Furnace Filter 101: How Often to Change Furnace Filter & More

August 19, 2025

If you're not sure how often to change a furnace filter in your home, you're not alone. It's one of the most overlooked yet important tasks in keeping your HVAC heating system running efficiently. A dirty filter doesn't just hurt airflow—it can hike up your energy bills and damage your system over time. Whether you're trying to boost your air quality or simply want to learn how to change a furnace air filter without the stress, Comfort Heating & Air is here to help.

Why Changing Your Furnace Filter Matters

Your furnace filter plays a bigger role than you might realize. It doesn't just protect your equipment—it protects the air you breathe. If you've ever wondered where the furnace filter is located, it's worth finding out in our step-by-step guide below, as keeping it clean can make a significant difference. Here's what a clean filter helps with:

Protects your HVAC system components
Improves indoor air quality
Lowers your energy bills
Extends your system's lifespan

Changing your filter is one of the simplest, most effective ways to care for your home.

How Often Should You Change Your Furnace Filter?

It's a question we get all the time, and the truth is, there's no one-size-fits-all answer. Still, some solid guidelines can help you stay on track:

Every 1–3 months for standard 1-inch filters
Every 6–12 months for high-efficiency filters or thicker options

But timing isn't everything. Your specific situation matters. Ask yourself:

Do you have pets that shed?
Does anyone in your home have allergies or asthma?
Is your HVAC system running constantly during extreme temperatures?
Do you live in a dusty or high-pollen area?
What type of filter are you using (standard vs. high-MERV)?

If you answered yes to any of these, you may need to change your filter more often. So next time you're wondering how often to replace a furnace filter, remember: it's not just about the calendar. It's about your air.

Signs It's Time for a Filter Change

You don't always have to rely on a set schedule. Your home and your HVAC system will give you clues when it's time. Watch for these signs:

Visible dirt or discoloration on the filter
More dust collecting on surfaces around your home
Weaker airflow from your vents
Furnace running longer than usual to maintain temperature
Unexplained spikes in your energy bill

How to Change Your Furnace Filter in 6 Easy Steps

Changing your furnace filter might sound intimidating, but it's a quick DIY task once you know what to do. Here's a simple walkthrough to help you do it safely and correctly:

Turn off your furnace: Always shut off the system first to prevent dust from circulating or the unit from kicking on during the change.
Locate the filter: Furnace filters are usually located in the blower compartment or behind the return air grill.
Note the airflow direction: Check the arrows on the old filter showing which way air flows through your system. You'll need to match this in step five.
Remove the old filter carefully: Slide it out gently to avoid shaking loose trapped dust and debris.
Insert the new filter: Ensure the airflow arrow on the new filter aligns with the one you removed.
Close everything up and restore power: Replace any covers or grates and turn your system back on.

Learning how to change a furnace air filter can save you time, money, and stress in the long run.

What Happens If You Don't Change the Filter?

Skipping filter changes might not seem like a big deal until your system starts acting up or your energy bills climb. Over time, a clogged filter can trigger more than just poor airflow. Here's what can happen:

Reduced heating and cooling efficiency, making your home less comfortable
Higher energy bills as your system works harder than it should
Poor indoor air quality
Increased wear and tear on internal components, leading to more frequent repairs
A shorter furnace lifespan, which can mean an expensive early replacement.

Changing the filter regularly is one of the easiest ways to prevent these issues and maintain your system's health. While no HVAC system lasts forever, taking care of this essential maintenance task can prolong the need for a replacement. Fortunately, when you do need a replacement, Comfort Heating & Air makes costs more manageable with flexible financing options.

Why Choose Comfort Heating & Air for All Your HVAC Needs

At Comfort Heating & Air, we're here to make the simple things, like knowing how often to change a furnace filter, even easier. When you join our Pro Service Plan, we'll help you stay on top of regular maintenance, including filter changes, so you never have to guess. You'll also enjoy priority service, discounts, and peace of mind knowing your system is backed by our exceptional service guarantee.

Need help with your furnace or HVAC system? Call us at 859-300-3785 or schedule your service online.