Quick answer: Once a year — January is as good a time as any — run a 10-minute filter reset: confirm your exact size, check you're on the right MERV, set a season-by-season change schedule, and stock the year's filters in one go. This checklist is the hub; each step links to the full how-to if you want the detail.
Most HVAC filter advice is scattered across a dozen questions: what size, what rating, how often, what changes by season. This is the once-a-year version that ties them together. Think of it as your annual reset — the ten minutes in January that set up clean, easy-breathing air for the other 51 weeks. Work down the list; follow the links only where you need them.
1. Confirm your exact filter size
Start here, because everything else depends on it. Pull your current filter and read the size printed on the cardboard edge (for example, 20x25x1). That's your nominal size — the number you order by. If it's worn off or you're setting up a new home, our Find My Filter tool and the how to measure an air filter guide walk you through it. A filter that doesn't fit the slot snugly lets air leak around the edges, so the rating on the box doesn't matter if the size is wrong.
2. Check you're actually on the right MERV
Plenty of homes have been running whatever the last person grabbed. Once a year, ask whether it's the right rating for your household. MERV 13 is the sweet spot for most homes; step up to MERV 14–16 only if you have a newer system with a strong blower, and drop to MERV 8–11 if your airflow is weak. Allergies, asthma, or pets in the house nudge you higher. The what MERV rating do I need guide covers the airflow trade-off honestly.
3. Set a change schedule that flexes by season
The biggest mistake is running one interval all year. Your filter loads faster in heavy-AC summers and closed-up winters than it does in mild months. Set reminders now: a 1-inch filter roughly every 30–90 days, tightened during peak seasons. Our how often to change your filter by season guide has the month-by-month version, and the signs you need to change your filter covers what to watch for between reminders.
4. Note the seasonal spikes you'll hit this year
A good annual reset means knowing what's coming so you're not caught flat. Skim these once and you'll know when to tighten the interval or add protection:
- Spring: tree and grass pollen — spring pollen filter guide.
- Summer: heavy AC load and humidity — best air filter for summer.
- Late summer / fall: ragweed and the first furnace start-up — ragweed allergy filter guide.
- Fire season: wildfire smoke — wildfire HVAC prep.
- Winter: a sealed-up house and constant heat — winter furnace filter guide.
5. Stock the whole year in one order
Here's the part that makes the schedule stick: buy your filters ahead, not one at a time. When a spare of your exact size is already on the shelf, you actually swap it on schedule instead of running a clogged one for an extra month. Because our flat-rate shipping is the same whether you buy one filter or a multipack, stocking the year in a single order costs nothing extra in shipping. Confirm your size, then grab the count you'll need from all Ironside filters.
Your 10-minute reset, in one list
- Pull the filter and confirm the exact size on the edge.
- Decide whether your MERV still fits your household and system.
- Set season-aware change reminders on your phone.
- Skim the seasonal spikes so nothing catches you off guard.
- Order the year's filters in one multipack of your size.
- Install the fresh one and note the date.
Frequently asked questions
How often should I do an HVAC filter reset?
Once a year is enough for the big-picture reset — confirming your size, rating, and schedule. The actual filter changes happen far more often, roughly every 30 to 90 days for a 1-inch filter depending on the season, but the annual reset is what keeps that routine on track.
Is January a good time to change my air filter?
Yes. After the holidays your home has seen extra guests, cooking, and closed-up indoor time, so the filter is usually loaded. January is also a natural moment to set reminders for the year. That said, the calendar month matters less than the filter's condition — if it looks dirty, change it whenever you notice.
How many air filters should I buy for the year?
Count your change intervals. A 1-inch filter changed every 60 days is about six a year; every 30 days in a heavy-use home is closer to twelve. Buy that many at once in a multipack of your exact size so you're never out. Since flat-rate shipping is the same for one filter or a multipack, ordering the year in one go saves trips without adding shipping cost.
Should I upgrade my MERV rating?
Upgrade if your household needs it — allergies, asthma, pets, or smoke concerns — and your system can push air through a denser filter. MERV 13 suits most homes. Only move to MERV 14–16 with a newer system and strong airflow; if your vents feel weak after an upgrade, drop back a tier.
Make the reset your one easy resolution. Start with Find My Filter to lock in your size, then stock the year from all Ironside filters. Built here. Breathe better.