--- product_id: 28445485 title: "FilterLock Furnace Filter Slot Seal – Magnetic Seal Cover for Any 1” Furnace Filter, Up To 25” Long, Reduce HVAC Air Leaks, Green" brand: "allergyzone" price: "840592₫" currency: VND in_stock: true reviews_count: 13 category: "Allergy Zone" url: https://www.desertcart.vn/products/28445485-filterlock-furnace-filter-slot-seal-magnetic-seal-cover-for-any store_origin: VN region: Vietnam --- # Energy efficient Magnetic seal system Improves air quality FilterLock Furnace Filter Slot Seal – Magnetic Seal Cover for Any 1” Furnace Filter, Up To 25” Long, Reduce HVAC Air Leaks, Green **Brand:** allergyzone **Price:** 840592₫ **Availability:** ✅ In Stock ## Summary > 🔧 Seal the air, save the planet! ## Quick Answers - **What is this?** FilterLock Furnace Filter Slot Seal – Magnetic Seal Cover for Any 1” Furnace Filter, Up To 25” Long, Reduce HVAC Air Leaks, Green by allergyzone - **How much does it cost?** 840592₫ with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.vn](https://www.desertcart.vn/products/28445485-filterlock-furnace-filter-slot-seal-magnetic-seal-cover-for-any) ## Best For - allergyzone enthusiasts ## Why This Product - Trusted allergyzone brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Save Green:** Reduce utility bills with energy-efficient sealing. - • **Breathe Easy:** Prevent allergens and harmful gases from entering your HVAC system. - • **Seal the Deal:** Eliminate air leaks and enhance indoor air quality. - • **Universal Fit:** One-size-fits-all design for hassle-free installation. - • **Long-lasting Performance:** Reusable magnetic design for enduring effectiveness. ## Overview The FilterLock Furnace Filter Slot Seal is a patented magnetic seal cover designed for 1” furnace filters up to 25” long. It effectively eliminates air leaks, enhancing indoor air quality and reducing energy consumption. Easy to install and reusable, this innovative solution addresses air leakage issues identified by Energy Star, ensuring a cleaner and more efficient HVAC system. ## Description Product description Boost Your HVAC Efficiency with FilterLock FilterLock is a patented magnetic seal system designed to cover your furnace filter slot, preventing unfiltered air from entering your HVAC system. Improve indoor air quality, reduce energy consumption, and enhance overall system performance with this easy-to-install, one-size-fits-all solution. Enhance Your HVAC Performance FilterLock: The Smart Solution for Cleaner Air and Energy Savings Introducing FilterLock by Allergy Zone, the innovative magnetic seal designed to optimize your HVAC system's performance. This patented, one-size-fits-all solution covers your furnace filter slot, preventing unfiltered air from entering your heating and cooling system. Easy to install and compatible with any 1-inch air filter up to 25 inches long, FilterLock helps improve indoor air quality and reduce energy consumption. Experience the difference of a properly sealed HVAC system with FilterLock – the professional choice for enhanced system integrity and cleaner, more efficient home comfort. Features Cover furnace filter slot/door Block allergens and other contaminants from entering home including deadly gases like carbon monoxide and radon Improve indoor air quality Reduce energy consumption Magnetically attaches to the duct work Two-piece design works with any 1” filter up to 25” long Universal one size fits all Indefinitely reusable Easy to install Review: Instantly Banish Dusty Air – Breathe Easier Now! - My home is 15 years old and has a furnace with a filter slot on the side that doesn’t have a cover, leading to dusty air leaking out. I bought the AllergyZone FilterLock Slot Seal to fix this, and I am extremely pleased with the results. Installation could not have been easier – it’s a two-piece magnetic strip that I just snapped over the open filter slot. It took literally seconds to attach, and it fit perfectly along the length of my 1-inch filter slot (no gaps at all). I immediately noticed that when the blower kicks on, there’s no longer a puff of dusty air coming out. The seal is nice and tight. The improvement in air quality was almost immediate in my home. I suffer from allergies, and I used to see dust collecting around the furnace closet and could smell a slight mustiness whenever the heat turned on. After using this FilterLock cover, that issue is gone – my air now feels cleaner and my HVAC system is pulling air only through the filter as intended. I even think my furnace is running more efficiently because no unfiltered air is bypassing the filter. It’s such a simple concept but works brilliantly. The magnets are strong enough that once it’s on, it stays put. I haven’t had any problems with it slipping off, and it’s easy to remove and reattach when I need to change the filter. Another plus is the material – it’s a durable vinyl that seems like it will last through many filter changes. It’s reusable, so this $20-something purchase will keep benefiting me indefinitely. I also appreciate that it’s a bright green color, which is a visual reminder to check my filter monthly. All in all, I’m very happy with the FilterLock Furnace Slot Seal. It solved an issue that had been bothering me for years in an affordable and effortless way. Every home with an open filter slot should have one of these. Five stars for making my air cleaner and my life easier! Review: Filter Lock Furnace Filter Slot Cover Review - Easy Fix, Inexpensive - This is an amazingly simple invention that finally solves a problem that we had in our house. The area where I slide in my filter in the furnace had big gaps on the sides, top and bottom. To make matters worse there was an opening on both sides of the furnace so that you could install the filters from either side. So the air was getting sucked in from both sides and probably very little was coming in from the cold air returns. It is beyond me why furnace installers have not figured out a way to fix this problem. I thought about calling someone to build a door or rework the metal so that there was a tighter fit but that would have cost a fortune. This little invention while perhaps not perfect, improved the situation 99%. I still may be getting some air going around the filter inside the cover but at least my system is relatively closed off so I am getting better air flow and I would not be surprised if this cuts down on my bills over time. This consists of two pieces of heavy duty plastic that measure 4.5" x 14" each. The plastic reminds me of the type that you would find on a pool liner. It's pretty tough but flexible. There is a magnetic strip inside the plastic on one end of each piece and two that run up each side. The magnets inside the plastic being broken into pieces allow you to fold them over in a couple places to get a good fit on your duct. Depending on how your duct work is constructed this may work better for some than others. I would urge you to take a look at my photos and then take a look at your ducts to see if this will work for you. For me it works perfectly at the bottom but at the top the way they constructed my ducts I have to fold it over and put it on a slight diagonal. I found that the magnets were strong enough to stick to my duct work but pliable enough that I could bend them at the top where I had issues with the way they fit in order to get a tight seal. They come in two pieces so that they can bend over on each side and still get an exact fit for a variety of sizes. The two pieces overlap enough that there is no air escaping. My filters are 16" at the opening. One thing I may do to make changing the filters and re positioning the covers easier is to tape the top edge and the bottom edge to the duct. It's not such a big deal for the bottom, but the top edge is wedged in to fit my odd fitting duct work so I think if I did not have to remove it completely to replace the filter that these will maintain a good fit longer. I felt these were a decent value for what I paid ($8 each) I had to buy 4 so it was $32 but I would have spend a lot more had I called someone to rework the duct area and install a cover. Plus some covers still do not seal off the opening completely. Thanks for reading my review Becky Brooks *I paid full price for this item it was not a free sample ## Features - PROTECT YOUR HVAC SYSTEM: FilterLock is a patented two-piece magnetic seal system designed for furnace systems with 1” air filters, eliminating air leakage at the filter slot/door to enhance indoor air quality and reduce energy consumption. - IMPROVE AIR QUALITY: Prevent harmful airborne contaminants such as allergens, dust, and gases like carbon monoxide from entering your HVAC system. Properly sealing the filter slot/door ensures that pollutants don’t bypass the air filter. - ENERGY EFFICIENT: Reduce utility bills and save energy by effectively stopping air leaks in your HVAC system. This not only enhances overall indoor air quality but also addresses one of the four major ductwork issues identified by Energy Star—air leakage at the filter slot. - EASY TO INSTALL: Enjoy hassle-free installation with FilterLock’s universal, one-size-fits-all seal that magnetically attaches to ductwork to cover the furnace filter slot door. This convenient two-piece design is compatible with any 1” furnace filter up to 25” long. - ADDITIONAL FEATURES: Benefit from a reusable, easy on/easy off magnetic design that ensures long-term use. Once both pieces are installed, the seal measures approximately 25 x 4.8 x 0.1 inches, providing a perfect fit for your needs. ## Images ![FilterLock Furnace Filter Slot Seal – Magnetic Seal Cover for Any 1” Furnace Filter, Up To 25” Long, Reduce HVAC Air Leaks, Green - Image 1](https://m.media-amazon.com/images/I/71xdDvfnNtL.jpg) ![FilterLock Furnace Filter Slot Seal – Magnetic Seal Cover for Any 1” Furnace Filter, Up To 25” Long, Reduce HVAC Air Leaks, Green - Image 2](https://m.media-amazon.com/images/I/71NPqmTe0YL.jpg) ![FilterLock Furnace Filter Slot Seal – Magnetic Seal Cover for Any 1” Furnace Filter, Up To 25” Long, Reduce HVAC Air Leaks, Green - Image 3](https://m.media-amazon.com/images/I/81Boxx-7ySL.jpg) ![FilterLock Furnace Filter Slot Seal – Magnetic Seal Cover for Any 1” Furnace Filter, Up To 25” Long, Reduce HVAC Air Leaks, Green - Image 4](https://m.media-amazon.com/images/I/71tXJiKP1PL.jpg) ![FilterLock Furnace Filter Slot Seal – Magnetic Seal Cover for Any 1” Furnace Filter, Up To 25” Long, Reduce HVAC Air Leaks, Green - Image 5](https://m.media-amazon.com/images/I/81cpgTgOLRL.jpg) ## Questions & Answers **Q: is this the reason why my furnace smell there is a gap? My furnace is in a small enclose room with drywall carry a little gap.** A: I am not sure exactly where this gap is? A furnace should not smell, at least not that bad. I don't think this product would stop that, but at the price worth a try. My suggestion is to try it & see if it works, but still contact a furnace specialist to make sure your furnace is working correctly. You also did not note if oil or gas fired, or heat pump? A heat pump should not smell at all, anytime! So more checking needs to be done, I think, for your safety. **Q: My furnace filter opening (just wider than the 1 inch filter) is recessed between the furnace and the insulation covered ductwork. Will this work?** A: It uses magnets to hold in place. If your duct is covered in insulation board, the magnets won’t work. They would only stick to the metal of the duct or to the metal furnace enclosure. Probably won’t work for you. **Q: Are furnaces required by health and safety code to have a cover on the filter slot?** A: I don’t think they are required or if they are that depends on the state and city or institution . Although the cleaner the filtered air is , the better quality will be **Q: It’s advertised that each piece is 25” long but I’ve seen some people say that each piece is only “14 can anyone confirm?** A: Each piece is 14" and comes with 2 pieces per package. You can also overlap the pieces on your furnace to fit various sizes. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Instantly Banish Dusty Air – Breathe Easier Now! *by C***Y on August 2, 2025* My home is 15 years old and has a furnace with a filter slot on the side that doesn’t have a cover, leading to dusty air leaking out. I bought the AllergyZone FilterLock Slot Seal to fix this, and I am extremely pleased with the results. Installation could not have been easier – it’s a two-piece magnetic strip that I just snapped over the open filter slot. It took literally seconds to attach, and it fit perfectly along the length of my 1-inch filter slot (no gaps at all). I immediately noticed that when the blower kicks on, there’s no longer a puff of dusty air coming out. The seal is nice and tight. The improvement in air quality was almost immediate in my home. I suffer from allergies, and I used to see dust collecting around the furnace closet and could smell a slight mustiness whenever the heat turned on. After using this FilterLock cover, that issue is gone – my air now feels cleaner and my HVAC system is pulling air only through the filter as intended. I even think my furnace is running more efficiently because no unfiltered air is bypassing the filter. It’s such a simple concept but works brilliantly. The magnets are strong enough that once it’s on, it stays put. I haven’t had any problems with it slipping off, and it’s easy to remove and reattach when I need to change the filter. Another plus is the material – it’s a durable vinyl that seems like it will last through many filter changes. It’s reusable, so this $20-something purchase will keep benefiting me indefinitely. I also appreciate that it’s a bright green color, which is a visual reminder to check my filter monthly. All in all, I’m very happy with the FilterLock Furnace Slot Seal. It solved an issue that had been bothering me for years in an affordable and effortless way. Every home with an open filter slot should have one of these. Five stars for making my air cleaner and my life easier! ### ⭐⭐⭐⭐⭐ Filter Lock Furnace Filter Slot Cover Review - Easy Fix, Inexpensive *by E***R on September 6, 2016* This is an amazingly simple invention that finally solves a problem that we had in our house. The area where I slide in my filter in the furnace had big gaps on the sides, top and bottom. To make matters worse there was an opening on both sides of the furnace so that you could install the filters from either side. So the air was getting sucked in from both sides and probably very little was coming in from the cold air returns. It is beyond me why furnace installers have not figured out a way to fix this problem. I thought about calling someone to build a door or rework the metal so that there was a tighter fit but that would have cost a fortune. This little invention while perhaps not perfect, improved the situation 99%. I still may be getting some air going around the filter inside the cover but at least my system is relatively closed off so I am getting better air flow and I would not be surprised if this cuts down on my bills over time. This consists of two pieces of heavy duty plastic that measure 4.5" x 14" each. The plastic reminds me of the type that you would find on a pool liner. It's pretty tough but flexible. There is a magnetic strip inside the plastic on one end of each piece and two that run up each side. The magnets inside the plastic being broken into pieces allow you to fold them over in a couple places to get a good fit on your duct. Depending on how your duct work is constructed this may work better for some than others. I would urge you to take a look at my photos and then take a look at your ducts to see if this will work for you. For me it works perfectly at the bottom but at the top the way they constructed my ducts I have to fold it over and put it on a slight diagonal. I found that the magnets were strong enough to stick to my duct work but pliable enough that I could bend them at the top where I had issues with the way they fit in order to get a tight seal. They come in two pieces so that they can bend over on each side and still get an exact fit for a variety of sizes. The two pieces overlap enough that there is no air escaping. My filters are 16" at the opening. One thing I may do to make changing the filters and re positioning the covers easier is to tape the top edge and the bottom edge to the duct. It's not such a big deal for the bottom, but the top edge is wedged in to fit my odd fitting duct work so I think if I did not have to remove it completely to replace the filter that these will maintain a good fit longer. I felt these were a decent value for what I paid ($8 each) I had to buy 4 so it was $32 but I would have spend a lot more had I called someone to rework the duct area and install a cover. Plus some covers still do not seal off the opening completely. Thanks for reading my review Becky Brooks *I paid full price for this item it was not a free sample ### ⭐⭐⭐⭐ It works *by W***G on September 16, 2025* Great concept. The more care used to place the pieces to achieve the most complete seal, the best results will be gained. Where the two pieces overlap, the center area has a potential small leak area. Nevertheless a vast improvement covering up this very leaky area. Fair value. ## Frequently Bought Together - AllergyZone FilterLock Furnace Filter Slot Seal – Magnetic Seal Cover for Any 1” Furnace Filter, Up To 25” Long, Reduce HVAC Air Leaks, Green - Simply 16x25x1 Air Filter, MERV 8, MPR 600, 6 Pack, For Home AC Furnace & HVAC (Actual Size: 15.75"x24.75"x0.75") DUST, Pet, & Allergy Control - Filtrete 16x25x1 AC Furnace Air Filter, MERV 11, MPR 1000, Micro Allergen Defense, 3-Month Pleated 1-Inch Electrostatic Air Cleaning Filter, 2 Pack (Actual Size 15.719 x 24.72 x 0.84 in) --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.vn/products/28445485-filterlock-furnace-filter-slot-seal-magnetic-seal-cover-for-any](https://www.desertcart.vn/products/28445485-filterlock-furnace-filter-slot-seal-magnetic-seal-cover-for-any) --- *Product available on Desertcart Vietnam* *Store origin: VN* *Last updated: 2026-06-06*