When you compare MERV 8 vs MERV 11, MERV 11 meets the higher minimum in the two larger particle bands and adds a minimum in the smallest band. Your furnace manual may list the highest grade the furnace takes, and an HVAC technician can tell you that grade when the manual does not. Either answer ends at a filter we sell, because our list carries both grades in the same 73 sizes.
MERV reports what a filter captures by particle size
MERV stands for Minimum Efficiency Reporting Value. The rating reports how well an air filter captures particles from 0.3 to 10 microns. ASHRAE developed the test method behind the rating, and the test standard is ASHRAE 52.2. The higher the rating, the better a filter captures particles of specific sizes.
The test range splits into bands by particle size. The smallest band covers 0.3 to 1.0 microns. Next comes the middle band from 1.0 to 3.0 microns, and the largest band covers 3.0 to 10.0 microns. A grade can set a different minimum for each band, because a filter can capture one size of particle better than another. MERV 8 and MERV 11 are two grades on this one scale, so you can compare them one band at a time.
MERV 11 captures more in every band the EPA lists
| Grade | 0.3 to 1.0 microns | 1.0 to 3.0 microns | 3.0 to 10.0 microns |
|---|---|---|---|
| MERV 8 | No figure in the EPA table | 20 percent or more | 70 percent or more |
| MERV 11 | 20 percent or more | 65 percent or more | 85 percent or more |
A MERV 11 filter captures at least one particle in five in the smallest band, where MERV 8 has no figure. In the middle band, the MERV 11 minimum of 13 in 20 is more than three times the MERV 8 minimum of one in five. The gap narrows in the largest band, with MERV 11 at 17 in 20 and MERV 8 at 14 in 20.
MERV 8 covers the two larger bands
Whether MERV 8 is good enough for a home depends on the bands where you want a minimum. A MERV 8 filter meets a minimum in the two larger bands and has no figure in the smallest band. Those two bands cover particles from 1.0 to 10.0 microns. If you want a minimum in the smallest band as well, pick MERV 11. When your furnace calls for MERV 8, MERV 8 is the grade to order.
All 68 pleated filters on each list have an electrostatic charge, and the charge draws airborne particles to the media. The other 5 sizes in each grade are deep media cabinet filters.
Your furnace sets the highest grade it can take
MERV 11 is too high for a home when the furnace cannot take that grade. A higher grade can put more load on the furnace blower. Your manual may list the highest grade your furnace can take. If it lists MERV 11 or a higher grade, a MERV 11 filter is within that limit. A MERV 8 filter is within that limit too. You can order either grade.
The EPA notes that you may need an HVAC technician to find the highest efficiency filter that works with your system. When your manual gives no grade, a technician can tell you whether your furnace takes MERV 11. If a technician already services your furnace, ask on the next visit. If you think you may want MERV 13 later, ask about that grade on the same visit. Once you know the highest grade, every reorder starts from it.
You can pick your grade in four steps
Keep your furnace manual and your old filter at hand for these steps.
- Check your furnace manual for the highest grade it may list.
- Ask an HVAC technician for the highest grade your furnace takes if the manual gives none.
- Pick the grade that fits your furnace and the bands you want.
- Pick MERV 11 when your furnace takes it and you want a minimum in the smallest band.
- Pick MERV 8 when your furnace calls for MERV 8.
- Order that grade in the nominal size printed on the cardboard frame of your old filter.
Both grades share one list of 73 sizes
In each grade, our list has 37 sizes at 1 inch deep, 22 at 2 inches, 9 at 4 inches and 5 for deep media cabinets. The 1 inch sizes make up just over half of each list. You can browse every size on our MERV 11 air filters page and our MERV 8 air filters page.
The size printed on the cardboard frame of your old filter is the nominal size, a rounded figure the industry uses as a label. Each product page also lists the actual size. Our 16x25x1 filter has an actual size of 15.5 x 24.5 x 0.75 inches. The actual size of our 20x25x1 filter is 19.5 x 24.5 x 0.75 inches. In both cases, the actual size comes in half an inch under the nominal size on each face and a quarter inch under on depth. Both actual sizes are the same in MERV 8 and MERV 11. For more help with sizes, read our guide to the sizes on the frame.
The pack size depends on the depth. Our 1 inch and 2 inch pleated filters ship as a 6 pack. That covers 59 of the 73 sizes on each list. Our 4 inch pleated filters ship as a 3 pack, and our deep media cabinet filters ship as a 2 pack. A switch between the two grades keeps both your size and your pack the same.
Our deep media filters fit Honeywell cabinets in 16x25x5, 20x20x5 and 20x25x5. Space Gard cabinets take our 16x28x6 and 20x25x6 filters. For Air Bear cabinets, we stock 16x25x5 and 20x25x5. In our list, every 6 inch cabinet size fits Space Gard, and every 5 inch size fits Honeywell or Air Bear. Since 16x25x5 and 20x25x5 appear under both Honeywell and Air Bear, pick the listing that matches the brand on your cabinet. Each cabinet filter comes in MERV 8, MERV 11 and MERV 13, like our pleated filters.
Change either grade on a schedule
Every air filter needs changing from time to time, and your furnace maker's recommendation sets the schedule. The usual practice is to change a 1 inch pleated filter every 90 days. You can usually go 6 to 12 months between changes with a 4 inch or deeper filter. Pets in the home or construction nearby shorten the time between changes for both. For a 2 inch filter, follow the schedule your furnace maker gives.
From those figures, you can work out how long a pack lasts. A 1 inch filter changed every 90 days means about four changes a year, so a 6 pack lasts about 18 months. At 6 month changes, a 3 pack of 4 inch filters lasts 18 months. At yearly changes, the same 3 pack lasts 3 years. With deep media filters, a 2 pack lasts 1 year at 6 month changes and 2 years at yearly changes.
When the reorder slips your mind, our Subscribe and Save plan ships your next pack on the interval you choose. You pick the plan on the product page when you order, and it ships that same pack each time. The plan ships every 3 months, every 6 months or every year.
Pick the interval closest to the time one pack lasts in your home. For each pack above, the yearly interval comes closest. If pets or construction mean more changes, a shorter interval may come closer. A 2 pack of deep media filters changed every 6 months matches the yearly interval exactly.
Skip the next pack while filters from the last one remain on your shelf. With 1 inch filters, about 12 changes over 3 years use two 6 packs, so you skip one yearly pack in three. You can adjust the interval later if your pace changes, and you can pause or cancel the plan.
MERV 13 is the next grade up
Above MERV 11, we stock MERV 13 in the same 73 sizes, with the same depths and packs. MERV 13 is the higher rating, so it captures particles of specific sizes better than MERV 11. The same manual check comes first, because your furnace manual may list a highest grade below MERV 13. When MERV 11 is the highest grade your furnace takes, stay with MERV 11. When your furnace takes MERV 13, all three of our grades are within its limit. Browse our MERV 13 air filters once you know that grade fits. For the step from MERV 11 to MERV 13, read our MERV 11 and MERV 13 comparison.
Your order starts with one call or one click
Call us at 855-789-3278, and we will help you match the size on your old frame and the grade from your manual to the right product page. Our MERV 11 media is changing to blue as the existing stock ships out first, and the quality stays the same.
Order your next pack from our MERV 11 air filters or our MERV 8 air filters, in the grade your furnace takes. Each page lists every size and cabinet fit in its grade.