Did You Know Your Natural Gas Water Heater Has an Air Filter?
Here’s a little secret most homeowners don’t realize: your natural gas water heater has an air filter—and if it gets dirty or clogged, your water heater might not work properly.
Yup. That big, quiet tank in the corner of your basement or utility room? It’s actually breathing. And just like we can’t breathe well with a dust mask on, your water heater can’t “breathe” if its filter is choked up with lint, pet hair, or dust.
Let’s walk through what that means, why it matters, and what you can do to keep things running smoothly.
Why Does a Gas Water Heater Need an Air Filter?
Gas water heaters need air to burn fuel. This process happens in the combustion chamber, where gas and air mix and are ignited to heat your water. If that air supply gets restricted, a few things can happen:
- The flame may burn weak or go out entirely
- The pilot light might not stay lit
- The water heater may shut down for safety
- You might get inconsistent hot water or longer recovery times
That’s where the air intake filter comes in. It helps clean the air coming in, but when it gets too dirty, it can actually block airflow instead.
Where Is This Filter, and How Do I Clean It?
Most modern natural gas water heaters have a mesh screen or filter near the bottom of the unit—sometimes underneath or around the base. It’s often part of what’s called an FVIR system (Flammable Vapor Ignition Resistance), which is required by code for safety.
Here’s how to clean it:
- Turn off the heater – For safety, shut off the gas or power and let the unit cool.
- Find the air intake – Usually it’s on the bottom or side. It might look like a screen or a mesh ring.
- Vacuum or brush off the filter – Use a vacuum with a hose attachment, or a soft brush, to gently remove dust, pet hair, lint, etc.
- Double check for obstructions – While you’re at it, make sure nothing is blocking airflow around the base.
Pro tip: Some units have a removable filter that you can take out, rinse off, and dry before reinstalling. Others are fixed in place and just need to be vacuumed.
How Often Should You Clean It?
For most homes, once or twice a year is plenty. But if you’ve got pets, a dusty basement, or your water heater sits near a laundry area? Check it more often—every 3–6 months isn’t a bad idea.
What Happens If You Don’t?
Over time, a clogged air filter can cause your water heater to:
- Run less efficiently (costing you more in gas)
- Struggle to stay lit (leading to service calls)
- Overheat and shut off
- Wear out components faster
And the worst part? It’s a super preventable issue.
A Quick, Free Way to Prevent Headaches
Cleaning your air intake filter takes maybe 5–10 minutes and doesn’t cost a dime—but it could save you hundreds in unnecessary service calls or premature replacement.
So next time you’re checking your smoke detector batteries or changing your furnace filter, add this to the list:
“Check water heater air filter.” Your future self will thank you when the hot water keeps flowing and everything just works.