--- product_id: 312123344 title: "Inline Filter Box 4\" with High Efficacy Filter" brand: "ac infinity" price: "€ 535.93" currency: EUR in_stock: true reviews_count: 13 category: "Ac Infinity" url: https://www.desertcart.fi/products/312123344-inline-filter-box-4-with-high-efficacy-filter store_origin: FI region: Finland --- # MERV 13 high efficacy filter 400 CFM max airflow 1mm thick cold-rolled steel Inline Filter Box 4" with High Efficacy Filter **Brand:** ac infinity **Price:** € 535.93 **Availability:** βœ… In Stock ## Summary > 🌿 Elevate your air game β€” because fresh air is the new luxury. ## Quick Answers - **What is this?** Inline Filter Box 4" with High Efficacy Filter by ac infinity - **How much does it cost?** € 535.93 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.fi](https://www.desertcart.fi/products/312123344-inline-filter-box-4-with-high-efficacy-filter) ## Best For - ac infinity enthusiasts ## Why This Product - Trusted ac infinity brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - β€’ **Seamless Integration:** Designed to fit 4-inch inline fans with precise aluminum duct flanges for easy installation and optimal airflow up to 400 CFM. - β€’ **Effortless Maintenance:** Slide lock door with soft neoprene seal offers quick, dust-free filter changes without compromising airtight performance. - β€’ **Quiet & Efficient Airflow:** Engineered to work silently with your HVAC system, reducing airborne pollutants while maintaining a peaceful environment. - β€’ **Breathe Cleaner, Live Better:** Includes a MERV 13 rated high efficacy filter that traps dust, dirt, lint, and odorsβ€”perfect for maintaining pristine indoor air quality. - β€’ **Built to Last, Built to Perform:** Heavy-duty 1mm cold-rolled steel frame ensures durability and weather resistance for long-term peace of mind. ## Overview The AC Infinity Inline Filter Box 4" combines rugged 1mm cold-rolled steel construction with a high-performance MERV 13 filter to deliver up to 400 CFM of clean, fresh air. Designed for seamless compatibility with 4-inch inline fans, it features a slide lock door with a neoprene seal for easy, dust-free maintenance. Ideal for professionals seeking reliable, whole-house HVAC filtration that combats dust, odors, and airborne particles while enhancing indoor air quality. ## Description AC Infinity Inline Filter Box 4" with High Efficacy Filter | Heavy-Duty Steel Build, Whole House HVAC Filtration Kit, Fits 4-Inch Inline Duct Fans for Fresh Air Intake and Ventilation - desertcart.com Review: Great box, worth the money! - Great filter box. Built with good materials. Hinges are smooth and the latch is solid and looks and works great. I used this for my fresh air intake with a motorized damper for my A/C system. The inlet and outlet flanges were true to size and the door sealed very well with no leakage. It was easy to install and remove the included filter. This is heavy gauge metal and makes the box have some weight to it, so be prepared to have a way to mount or hang it. It's easy to tell this is a good product. The shipping box and packing were really nice....I hated to throw it away. You get quality with this box, it's worth the money, which is hard to find these days. Review: Great Fresh Air System - Filter Out Wildfire Smoke - I live in an area plagued by wildfire smoke and every year gets worse. I live in a Valley so temperature inversions are common and many of my neighbors have wood buring stove and some even illegally burn thei household garbage. I have indoor air cleaners which keep my indoor air quality index (AQI) very low, 1 to 4. However, Carbon Dioxide (CO2) levels get very high, especially in the bedroom when it can reach as high a 1400 ppm in the morning. Anything above 1000 ppm can cause headaches, fatigue, and other health issues. I assembled the system pictured it consists of the following: * AC Infinity Inline Filter Box fitted with Filterbuy 12x20x1 MERV 13 rated filters * AC Infinity Cloudline Pro S4 Inline Duct Fan * AC Infinity Flexible 4-inch Aluminum 4 layer HD Flex Hose (25') * Broan-NuTine 465B 4" to 5" Duct Adaptor * Gulrear Portable AC Window Vent Kit 5" I assembled these components and it allows me to draw in air from the outside, filter it, and disperse into the room. The 25' hose allowed me to place the outlet just below the top of the ceiling where monitoring have indicated is the best location. I use the IQ Air Airvisual Pro N1 indoor air quality monitor in the bedroom to track the AQI Index and most importantly for this purpose, the CO2 level. Prior to installing this system my highest reading in the morning averaged 950 ppm. Now I average 650 ppm. My 24 hour/day monthly average went from 735 ppm to 588 ppm. I am very pleased with the performance of the system and achieved my goal of reducing CO2 levels when I am unable to open the windows due to unhealty outdoor air quality. The AC Infinity products are of excellent quality and the inline Duct Fan is very quiet. I leave set at the 5 (out of 10) power level and it is very quiet. The combination of my air cleaner and the AC Infinity fan makes a great white noise level for restful sleep. In the pictures you will see how I have hidden some of the components under a chair. You can also see the hose outlet hidden behind the flower vase on top of the armoire. Update: Condensation inside the filter box was a concern, but with outside temps since installing in mid-October ranging from 65Β° to 22Β° F we have had zero moisture build up inside the filter box. Dry as a bone. ## Features - A duct filter box designed for use with inline fans to circulate fresh air and block dust and odors. - Built with 1mm thick cold-rolled steel and aluminum duct flanges, able to withstand extreme weather. - Slide lock door gives easy access to inner chamber while soft neoprene layer creates dust-free seal. - Includes a standard high efficacy filter that traps particles like dust, dirt, lint, and odor. - 23.46 x 8.42 x 11.73” | Fits 4” Inline Fans | 400 CFM Maximum | Accepts 12 x 20 x 1” Filters ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B0921N33Y7 | | Best Sellers Rank | #62,988 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #466 in Furnace Filters | | Brand | AC Infinity | | Brand Name | AC Infinity | | Compatible Devices | CLOUDLINE S4, CLOUDLINE T4 | | Compatible Hvac Systems | residential | | Customer Reviews | 4.6 out of 5 stars 334 Reviews | | Filter Shape | Rectangular | | Item Dimensions L x W x Thickness | 23.46"L x 8.42"W x 11.73"Th | | Item Highlight | Heavy-Duty Steel Build, Whole House HVAC Filtration Kit, Fits 4-Inch Inline Duct Fans for Fresh Air Intake and Ventilation | | Item Weight | 6.42 kg | | MERV Rating | 13 | | Manufacturer | AC Infinity | | Manufacturer Part Number | AC-AFB | | Material | Alloy Steel | | Material Type | Alloy Steel | | Model Number | AC-AFB4 | | Number of Items | 1 | | Number of Packs | 1 | | Product Dimensions | 23.46"L x 8.42"W x 11.73"Th | | UPC | 819137021693 | | Unit Count | 1 Count | ## Product Details - **Brand:** AC Infinity - **Compatible Devices:** CLOUDLINE S4, CLOUDLINE T4 - **Item Weight:** 6.42 kg - **MERV Rating:** 13 - **Manufacturer:** AC Infinity - **Material:** Alloy Steel - **Number of Items:** 1 - **Number of Packs:** 1 - **Product Dimensions:** 23.46"L x 8.42"W x 11.73"Th - **UPC:** 819137021693 ## Images ![Inline Filter Box 4" with High Efficacy Filter - Image 1](https://m.media-amazon.com/images/I/41EWnjz-1aS.jpg) ## Available Options This product comes in different **Size** options. ## Questions & Answers **Q: what filter fits perfect in the 4" filter box?** A: the 4" and 6" filters take 12x20x1" filters; the 8 and 10" box's take 14x20x1" filters **Q: What filter replacement is suggested for the 6" filter box? standard 20x12x1 does not fit.** A: Different brands of filters have different "actual" sizes. Look up the true size of the filter you are using, then check actual filter sizes for different brands that are smaller. **Q: Do the filters trap smoke from pipes or pollen and mildew?** A: No, you need a carbon filter for smoke **Q: Can I use a MERV 17 or HEPA filter instead of a MEV13 filter for additional filtration if they will even fit?** A: I use the HDX FPR 12 Ultimate Allergen with odor reduction. This filter is a higher end filter. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Great box, worth the money! *by T***D on October 8, 2025* Great filter box. Built with good materials. Hinges are smooth and the latch is solid and looks and works great. I used this for my fresh air intake with a motorized damper for my A/C system. The inlet and outlet flanges were true to size and the door sealed very well with no leakage. It was easy to install and remove the included filter. This is heavy gauge metal and makes the box have some weight to it, so be prepared to have a way to mount or hang it. It's easy to tell this is a good product. The shipping box and packing were really nice....I hated to throw it away. You get quality with this box, it's worth the money, which is hard to find these days. ### ⭐⭐⭐⭐⭐ Great Fresh Air System - Filter Out Wildfire Smoke *by M***S on December 3, 2023* I live in an area plagued by wildfire smoke and every year gets worse. I live in a Valley so temperature inversions are common and many of my neighbors have wood buring stove and some even illegally burn thei household garbage. I have indoor air cleaners which keep my indoor air quality index (AQI) very low, 1 to 4. However, Carbon Dioxide (CO2) levels get very high, especially in the bedroom when it can reach as high a 1400 ppm in the morning. Anything above 1000 ppm can cause headaches, fatigue, and other health issues. I assembled the system pictured it consists of the following: * AC Infinity Inline Filter Box fitted with Filterbuy 12x20x1 MERV 13 rated filters * AC Infinity Cloudline Pro S4 Inline Duct Fan * AC Infinity Flexible 4-inch Aluminum 4 layer HD Flex Hose (25') * Broan-NuTine 465B 4" to 5" Duct Adaptor * Gulrear Portable AC Window Vent Kit 5" I assembled these components and it allows me to draw in air from the outside, filter it, and disperse into the room. The 25' hose allowed me to place the outlet just below the top of the ceiling where monitoring have indicated is the best location. I use the IQ Air Airvisual Pro N1 indoor air quality monitor in the bedroom to track the AQI Index and most importantly for this purpose, the CO2 level. Prior to installing this system my highest reading in the morning averaged 950 ppm. Now I average 650 ppm. My 24 hour/day monthly average went from 735 ppm to 588 ppm. I am very pleased with the performance of the system and achieved my goal of reducing CO2 levels when I am unable to open the windows due to unhealty outdoor air quality. The AC Infinity products are of excellent quality and the inline Duct Fan is very quiet. I leave set at the 5 (out of 10) power level and it is very quiet. The combination of my air cleaner and the AC Infinity fan makes a great white noise level for restful sleep. In the pictures you will see how I have hidden some of the components under a chair. You can also see the hose outlet hidden behind the flower vase on top of the armoire. Update: Condensation inside the filter box was a concern, but with outside temps since installing in mid-October ranging from 65Β° to 22Β° F we have had zero moisture build up inside the filter box. Dry as a bone. ### ⭐⭐⭐⭐⭐ Very high quality filter box! *by R***T on August 5, 2026* It's just a filter box, but I'm so impressed with the high quality and craftsmanship. Well worth the cost. I've seen YouTube videos of people building their own filter boxes, and I question why they are doing so, when such a high quality box is available at a good price. ## Frequently Bought Together - AC Infinity Inline Filter Box 4" with High Efficacy Filter, Whole House HVAC Filtration Kit, Fits 4-Inch Inline Duct Fans for Fresh Air Intake and Ventilation - AC Infinity CLOUDLINE PRO S4, Quiet 4” Inline Duct Fan with Speed Controller – EC Motor Ventilation Exhaust Fan for Heating Cooling Booster, Grow Tents, Hydroponics - AC Infinity Flexible 4-Inch Aluminum Ducting, Heavy-Duty Four-Layer Protection, 8-Feet Long for Heating Cooling Ventilation and Exhaust --- ## Why Shop on Desertcart? - πŸ›’ **Trusted by 1.3+ Million Shoppers** β€” Serving international shoppers since 2016 - 🌍 **Shop Globally** β€” Access 737+ million products across 21 categories - πŸ’° **No Hidden Fees** β€” All customs, duties, and taxes included in the price - πŸ”„ **15-Day Free Returns** β€” Hassle-free returns (30 days for PRO members) - πŸ”’ **Secure Payments** β€” Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** β€” Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.fi/products/312123344-inline-filter-box-4-with-high-efficacy-filter](https://www.desertcart.fi/products/312123344-inline-filter-box-4-with-high-efficacy-filter) --- *Product available on Desertcart Finland* *Store origin: FI* *Last updated: 2026-09-23*