Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.
Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.
Changing the air filter is the one maintenance task on a central heating and cooling system that a householder can do without tools, and it is the task most often skipped. ENERGY STAR asks you to inspect the filter once a month and to change it at least every three months. A blocked filter slows the airflow, raises the running cost, and can damage the equipment.
This page gives the sequence, the two intervals that come from a government source, and the two values that no general source can supply for your equipment. Filter size and the highest efficiency rating your system will accept are specific to your model. Both are marked unverified here on purpose.
| Item | Note |
|---|---|
| New air filter | The size must be the same as the used filter. |
| Bag for the used filter | A refuse bag is sufficient. |
| Marker pen | For the date on the frame of the new filter. |
| Flashlight optional | Some filter slots are in a dark space. |
| Screwdriver optional | Only if the cover of the filter slot has screws. |
Source: What is a MERV rating? · tier 1 · accessed 2026-07-28
Source: What is a MERV rating? · tier 1 · accessed 2026-07-28
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
Estimated 2 min
SET THE THERMOSTAT TO OFF BEFORE YOU OPEN THE FILTER SLOT.
The blower can start without warning and injure your hand.
Estimated 2 min
Hold the used filter level.
Dust falls from a used filter and can go into the equipment.
Estimated 1 min
Source: Maintenance Checklist · tier 1 · accessed 2026-07-28
Source: Heat & Cool Efficiently · tier 1 · accessed 2026-07-28
Estimated 2 min
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
Do not increase the efficiency rating of the filter without advice.
The EPA says that an HVAC technician must find the highest efficiency that your system accepts.
Make sure that the airflow arrow points to the blower.
A filter in the wrong direction decreases the airflow. This can cause damage to the equipment.
Estimated 2 min
This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.
Stop if you cannot find the filter slot. Stop if the cover has damage. Stop if the used filter is wet. Speak to an HVAC technician.
Also stop if the equipment does not start after you install the new filter. Do not open the cabinet of the equipment. The work behind that cover needs a trade qualification.
The EPA says that an HVAC technician must find the highest filter efficiency for your system. Ask the technician for that value. Record the value with the size of the filter. Then this page is sufficient for each replacement after the first.
ENERGY STAR says to inspect, clean or change the filter once a month, and to change it at least every three months. Heavy use months matter most, so a filter that looks clean in April can be grey by August. Households with pets, smokers or building work usually need a shorter interval.
The airflow arrow points in the direction the air moves, which is away from the return duct and towards the blower and the equipment. If you are unsure, note the direction of the old filter before you remove it. A filter fitted backwards restricts airflow.
The EPA recommends at least MERV 13, or as high a rating as your system fan and filter slot can accommodate. MERV describes how well a filter captures particles between 0.3 and 10 microns. Higher is not automatically better: the EPA says an HVAC technician may be needed to determine the highest efficiency filter your particular system can use.
The size is printed on the cardboard frame of the filter already in the slot, and it is also in the documentation supplied with your equipment. This page does not print a size, because filter dimensions are specific to one model and a guessed size does not seal. Record the size once and the next purchase takes ten seconds.
No. This procedure covers the air filter in a central forced-air heating and cooling system only. Water filters, humidifier pads and range hood filters are separate items with their own intervals.
Yes. ENERGY STAR states that a dirty filter slows down air flow and makes the system work harder, which wastes energy, and that a dirty filter can increase energy costs and damage your equipment, leading to early failure.
No related procedure is published yet. This section fills as the repository grows.
Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.
Current version 1 · updated 2026-07-28 · next review due 2027-07-28
Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.
Found an error? A correction with a manufacturer source is applied and logged publicly. You can also write to corrections@fixchecklist.com.
Every step above carries its own report control, which tags the report with that step so a correction reaches the right place. For anything about the procedure as a whole — the order of the sections, a step that is missing, something that did not match your equipment — use this: report something about this whole procedure.