HVACQuick CFB Series MERV-13 Inline Filter Boxes

A CFB filter box from HVACQuick is a high-performance solution for any application requiring in-line filtration. Constructed from 5052 H32 aluminum, the CFBs holds a standard 4" filter and are designed to fit either 6", 8", 10" or 12" diameter duct. The lid attaches securely with latches, and opens easily for quick filter replacements. A single MERV-13 filter is included with every unit.

Does your application require higher arrestance or carbon filtration?  MERV-15 (near HEPA filtration) and CARBON IMPREGNATED FILTERS are now available to replace the standard filters.

Large orders are welcome, and may benefit from additional quantity discounts. Call us for more information or for resale opportunities. Note some assembly is required.

model description usually ships 1-2 units 3+ units QTY
CFB-6 HVACQuick CFB series inline filter box. For 6 inch ducts. Includes lid and MERV-13 filter - 14x14x4 inch (13.5x13.5x3.75 actual). 1 Day. In-stock $136.00 $124.00
CFB-8 HVACQuick CFB series inline filter box. For 8 inch ducts. Includes lid and MERV-13 filter - 18x18x4 inch (17.5x17.5x3.75 actual). 1 Day. In-stock $179.00 $166.00
CFB-10 HVACQuick CFB series inline filter box. For 10 inch ducts. Includes lid and MERV-13 filter - 24x24x4 inch (23.75x23.75x3.75 actual). 1 Day. In-stock $249.00 $237.00
CFB-12 HVACQuick CFB series inline filter box. For 12 inch ducts. Includes lid and MERV-13 filter - 24x24x4 inch (23.75x23.75x3.75 actual). 1 Day. In-stock $249.00 $237.00
CFB-6-OS HVACQuick CFB series inline filter box. Oversized filter section and 6 inch duct connections. Includes lid and *** MERV-15 FILTER ***. Filter is 24x24x4 inch (23.75x23.75x3.75 actual). 1 Day. In-stock $299.00 $279.00
PF13-14X14X4 Premium replacement filter for CFB-6. 14x14x4 (13.5x13.5x3.625) MERV 13 filter. 1 filter. 1 Day. In-stock $19.80 $17.80
PF13-18X18X4 Premium replacement filter for CFB-8. 18x18x4 (17.5x17.5x3.625) MERV 13 filter. 1 filter. 1 Day. In-stock $26.30 $23.90
PF13-24X24X4 Premium replacement filter for CFB-6-OS, CFB-10 & CFB-12. 24x24x4 (23.5x23.5x3.625) MERV 13 filter. 1 filter. 1 Day. In-stock $28.80 $26.20
PF15-14X14X4 Premium UPGRADE MERV 15 PLUS filter. 14x14x4 (13.5x13.5x3.75). Near HEPA filtration. 1 replacement filter for CFB-6. 3-4 Days $92.00 $91.00
PF15-18X18X4 Premium UPGRADE MERV 15 PLUS filter. 18x18x4 (17.5x17.5x3.75). Near HEPA filtration. 1 replacement filter for CFB-8. 3-4 Days $93.00 $91.00
PF15-24X24X4 Premium MERV 15 PLUS filter. 24x24x4 (23.75x23.75x3.75). Near HEPA filtration. 1 replacement filter for CFB-6-OS, CFB-10 & CFB-12. 1 Day. In-stock $95.00 $91.00
FO14X14X4-1FILTER 14x14x4 (13.5x13.5x3.75 Actual Size). Replacement MERV-10 CARBON impregnated filter for CFB-6. 1 filter. 1 Day. In-stock $27.40 $24.90
FO18X18X4-1FILTER 18x18x4 (17.5x17.5x3.75 Actual Size). Replacement MERV-10 CARBON impregnated filter for CFB-8. 1 filter. 1 Day. In-stock $31.50 $27.99
FO24X24X4-1FILTER 24x24x4 (23.75x23.75x3.75 Actual Size). Replacement MERV-10 CARBON impregnated filter for CFB-6-OS, CFB-10 & CFB-12. 1 filter. 1 Day. In-stock $39.30 $36.70
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Inline Filter Box Dimensions

Inline Filter Box MERV 15 specifications

Inline Filter Box

Inline Filter Box Closed

Do you have questions about the products on this page?

Click on the ? image on the left or this link to ask us your questions!
#1 Q:   In climate zone 5, if this is installed before the ERV, will there be an issue since it is not insulated? Can it be modified in some way if it is an issue?
A:   Should not be too much of an issue. Fantech recommends insulated flex on the HRV so that should negate most potential issues. Certainly could insulate the box as well for further protection.

       Asked on 2023-10-21 by Jonathan
#2 Q:   If used for fresh air intake with a Merv-13 filter, should this be used after a pre-filter?
A:   Assuming you are using an HRV/ERV it should be on the fresh air intake side before the air enters the HRV/ERV. So yes, a pre-filter for the air entering the HRV.

       Asked on 2023-03-18 by Stephen
#3 Q:   We have a fantech flex 100hs e 104cfm hrv. Will this filter box work with this hrv?
A:   Yes, you can use an CFB with that HRV. You will loose a small amount of airflow but not much since the CFB filter area is quite large for the airflow. You can remove the filter inside the HRV on the fresh air intake side of the core since the CFB will be your filter for the intake air. That assumes you will install the CFB on the fresh air intake side just before the air goes into the HRV.

       Asked on 2022-12-16 by Josh
#4 Q:   Ive ordered the CFB-6 as a pre-filter for a residential ERV installation. I now realize that I will have to stick to 4 ducting due to space constraints, rather than the 6 I had initially planned. Is there any reason why I shouldnt use this filter and tie it into the 4 ducting using two 6 to 4 reducers?
A:   No problem with doing that. Presumably your airflow is correct for 4 inch duct.

       Asked on 2022-12-03 by Noe
#5 Q:   My ERV has a MERV-13 filter. I want the option of MERV-15 when forest fires are bad, usually a few weeks a year. Can I put this in line with the ERV and leave the filter out most of the time? Would you put it on the way into the ERV our out of the ERV?
A:   You can take the filter out of the ERV and put a filter into the CFB for the smoke season. I would not run the ERV with both filters inserted as that is a lot of pressure drop for the ERV to handle. The CFB should be on the air coming into the ERV - filter the incoming air into the unit.

       Asked on 2022-08-21 by Cindi
#6 Q:   Hello, I received a CBF-6 filter box. In the images online, they appear to be riveted together (already built). However, what I received wasnt put together. Is it on me to seal these two ends together with my own rivets or screws?
A:   The CFB comes with screws and nuts to attach one of the cones to the main body. The cone is not attached to keep the shipping box smaller and shipping costs more reasonable. We could ship these with both cones attached, if requested, but that would probably require pallet shipment depending on the size. Please see the assembly manual under the links tab. Thanks.

       Asked on 2022-04-27 by Tony
#7 Q:   is it possible to get a 24x24x4 filter with 8 openings? a cfb-8-os?
A:   We could custom make them but there would have to be a minimum quantity on the order. Please contact us at 888-855-7229 if interested. Thanks.

       Asked on 2021-12-23 by Tim
#8 Q:   What is the benefit of the carbon impregnated filter over the normal Merv-13
A:   The carbon impregnated filters are better absorbing smells like cigarette smoke. They are approx MERV 10 so lower filtering efficiency than the MERV 13.

       Asked on 2021-11-11 by James
#9 Q:   Im interested in your CFB product for a low flow ERV application. The homeowner wants constant internal filtering in the ERV ducting, and the ERV itself supplements air from outsides few times a day. The system runs at 150 CFM.Due to the logistics of the mechanical room, I was wondering if i could use/purchase only half of the cone attached to ducts, and the other half open through the wall, covered by a custom louver. Ideally, the filter would be changed by removing the louvre.
A:   The way these are built, they require both sizes of the box to maintain the structure. It would not be practical to remove the back panel/cone. You would probably have better success with an openable louver and a sheet metal square to round transition with a filter inserted into the transition.

       Asked on 2021-02-28 by Steven
#10 Q:   What is merv rating of your carbon filters? How long they usually lasts if used with ERV system 24/7?
A:   There is no official merv rating on these. Our impression is they are a mid range filter in terms of capture. The length of service will depend on how dirty the air is you are filtering. 3 months is the normal rule of thumb but will vary.

       Asked on 2021-02-20 by george
#11 Q:   It is better to install the filter box before or after my inline blower?
A:   Before the blower so that your blower is getting filtered, clean air.

       Asked on 2021-01-26 by Dave
#12 Q:   I am trying to size a filter for a system that will flow, maximum, 1500 cfm. Not worried at all about pressure drop across the filter. From my calculations, across a 23.75^2 filter, Im going to get a velocity of about 383 ft/min.It appears CFB-12 is suitable for the task, but Id really prefer to have a MERV-15 filter, but youre only including it with the CFB-6-OS.Can your MERV-15 filter handle that velocity? Can I get a CFB-12, but substitute the MERV-15 instead of the MERV-13?
A:   Yes, that is in the allowable range for the CFB-12. Order the CFB-12 and the MERV-15 filter and include in the order checkout notes that you would like to not have the MERV-13 filter included. We will deduct the MERV-13 filter cost from the order before processing. Or call in your order.

       Asked on 2020-09-15 by msb
#13 Q:   Regarding CFB-6-OS. My understand is that its a 24x24 box, but with a 6 inlet/outlet. Does the 6 inlet/outlet taper outwards to a ~20 OD when entering the rectangular section?
A:   Correct. The main body is from a CFB-10/12 with a cone taper to a 6 inch on both sides of the main body. Its used where you have low airflows and need a large filter area for minimum pressure drop.

       Asked on 2020-09-10 by MB
#14 Q:   Do you just sell the filter box assembly? Without filter?
A:   Yes. You can place the order for the CFB and specify in the order notes you want the filter left out. We will subtract the filter cost and adjust the order.

       Asked on 2020-09-09 by MSB
#15 Q:   What would be a recommendable spacer inside this unit if i were to run two thinner filters (merv8/13), and would that affect performance?
A:   We highly recommend sticking with 1 4 inch filter. They have much more surface area than thinner filters due to the deep pleating and a lower pressure drop.

       Asked on 2020-07-25 by Matt
#16 Q:   So if I want to install this product, do I need to replace my current fan motor (currently 1/3hp)? If so, how my HP do I need? or would it be easier/cheaper to also install an inline fan to help pull more air? Thank you for your time.
A:   These are typically paired with an inline fan to pull the air through the filter. We list Typical/High/Low air flows for each box under the Specs tab so you can select a fan.

       Asked on 2020-03-29 by Terry
#17 Q:   Im looking for MERV 13 plus carbon filters to work with a heat recovery outside air unit. MERV 8 pre-filters are desired ahead of the MERV 13, to keep the MERV 13 from loading too quickly. Does this require a stack of the three different filters in line? Will the carbon filter act as a pre-filter in lieu of a separate MERV 8 filter? For an 1100 sf space, air flow is 500 to 600 cfm. What would be pressure drop for each 4 thick, in-line filter needed for this application?
A:   You can substitute the 4 inch filter for 2 qty 2 inch filters as long as the overall thickness works (you might need to insert a wedge/spacer since you would have a double undercut on the thickness). Pressure drop will vary depending on the box/filter size. Here are the carbon impregnated filters that we sell: https://hvacquick.com/products/residential/Air-Filters/Carbon-Air-Filters/Accumulair-two-inch-CARBON-filters

       Asked on 2019-05-23 by Kenneth
#18 Q:   What is the temperature rating on unit and filter
A:   No temperature rating specified. Standard HVAC system and air intake conditions. If you have specific requirements please give us a call at 877-711-4822 and we can have engineering take a look.

       Asked on 2018-10-24 by Eli
#19 Q:   What is the max CFM for this filter box ?
A:   Depends on the size. You typically want to keep filters at 300 feet per minute or less, so for the 24x24 filter that corresponds to roughly 1200 cfm.

       Asked on 2018-02-16 by Ron

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