Replace your HVAC filter
Quarterly · typically January, April, July, and October
Why it matters
Every bit of air your system heats or cools passes through one filter. When it loads up with dust, the system doesn't stop working — it works harder, quietly, on every cycle.
The quarterly schedule is the honest default. Pets, allergies, or a dusty gravel road? Check monthly — hold the filter up to a light; if you can't see light through it, it's done.
What skipping it costs
$450–$1,500
A choked filter makes the blower motor pull harder every hour it runs, and it's the #1 preventable cause of a frozen evaporator coil. That's a $450 service call in a good case — a cooked blower motor in a bad one, and those run $600–$1,500 installed.
Two ways to get it done
Do it yourself
You'll need: Replacement filter — the size is printed on the edge of the old one (~$8–$25).
- Find the filter: in the return grille on a wall or ceiling, or in a slot where the return duct meets the air handler.
- Kill the system at the thermostat first — no sense pulling dust into an open blower.
- Note the size on the old filter's edge (like 16x25x1) and the airflow arrow direction.
- Slide the new one in with the arrow pointing toward the unit (with the airflow, not against it).
- Write the date on the filter's edge with a marker. Future-you will thank present-you.
On ratings: MERV 8–11 is the sweet spot for most homes. Higher isn't automatically better — a MERV 13 in a system not designed for it restricts airflow and recreates the exact problem you're trying to prevent.
Hire it out
$75–$125National fair range — local labor moves this number.
Don't. A standalone filter-change visit runs $75–$125 in your area as a trip charge, and you'd be paying a licensed tech to do five minutes of work you can do in slippers. The only version that makes sense is having the tech swap it during a checkup that's already happening — which any honest one does without being asked. If a company is pushing a filter subscription, check their per-filter price against the hardware store before you sign anything.
Ask the tech
- What MERV rating are you installing, and why that one for my system?
- Can you show me where the filter lives so I can do this myself next time?
Red flags you're being upsold
- A 'filter subscription' through a service company at $30+ per filter — the same filter is $12 at the hardware store.
- Anyone selling a MERV 13+ filter without checking whether your blower can handle the restriction.
The call
DIY this forever. It's the single easiest thing you'll do for your house all year — there is nothing to hire.