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The best alternative to air purifier for wildfire smoke is often a DIY box fan with MERV 13 filters, which EPA testing showed can cut indoor smoke when commercial purifiers are scarce or too expensive.
We compared 5 alternatives by tested CADR, cost and safety.
Quick Answer: The Best Alternative to Air Purifier for Wildfire Smoke
- Best DIY Filter Pack: BNX TruFilter 20x20x1 MERV 13 Air Filter, 4-Pack
- Best DIY Fan Base: Amazon Basics 3-Speed 20-Inch Box Fan
- Best HVAC Upgrade: Filtrete 20x25x1 Air Filter, MERV 13, MPR 1900, 2-Pack
- Best Filter Upgrade: Levoit Core 300-P Smoke Remover Replacement Filter
- Best Odor Add-On: 16 x 48 Inch Cut-to-Fit Carbon Filter Sheet
The BNX 20×20 MERV 13 Filters is the best alternative to air purifier for wildfire smoke for most smoke-season households. The Amazon Basics 20-Inch Box Fan earns “Best DIY Fan Base”, and the Filtrete MERV 13 HVAC Filter earns “Best HVAC Upgrade”.
Best Alternative to Air Purifier for Wildfire Smoke Comparison Table
| Product | Best For | Type | Key Feature | Buy |
|---|---|---|---|---|
| BNX TruFilter 20x20x1 MERV 13 Air Filter, 4-Pack | Best DIY Filter Pack | MERV 13 filter (box fan DIY or HVAC) | MERV 13 pleated media | Check Price |
| Amazon Basics 3-Speed 20-Inch Box Fan | Best DIY Fan Base | 20-inch box fan | 3 speeds, 67 W, 5.8 lb | Check Price |
| Filtrete 20x25x1 Air Filter, MERV 13, MPR 1900, 2-Pack | Best HVAC Upgrade | MERV 13 furnace / AC filter | Captures fine allergens in the HVAC system | Check Price |
| Levoit Core 300-P Smoke Remover Replacement Filter | Best Filter Upgrade | Genuine smoke filter | 4-stage, with 2 extra dual-sided pre-filters | Check Price |
| 16 x 48 Inch Cut-to-Fit Carbon Filter Sheet | Best Odor Add-On | Cut-to-fit carbon pre-filter | 16 x 48 x 1/8 in | Check Price |
The 5 Best Alternatives to a Wildfire Smoke Purifier
Each pick below was compared on smoke CADR, coverage, carbon, filter supply and value.
BNX TruFilter 20x20x1 MERV 13 Air Filter, 4-Pack
1BNX 20x20x1 MERV 13 filters fit 20×20 HVAC returns and are popular for DIY box fan air cleaners.
👍 Pros & Cons
Pros
- Fits 20-inch box fans
- MERV 13
- 4-pack
Cons
- DIY fan setup is louder than a purifier
📄 Detailed Review
- Type: MERV 13 filter (box fan DIY or HVAC)
- Fits: 20x20x1 HVAC returns or a 20-inch box fan
- Key feature: MERV 13 pleated media
Strapping a MERV 13 filter to a box fan is a low-cost way to filter one room.
Place the filter on the intake side and never leave the fan unattended.
2The Amazon Basics box fan is a 20-inch, 3-speed fan that weighs 5.8 lb.
👍 Pros & Cons
Pros
- 20-inch size fits 20×20 filters
- Three speeds
- Light with carry handle
Cons
- A fan, not a purifier on its own
📄 Detailed Review
- Type: 20-inch box fan
- Includes: 1 fan
- Key feature: 3 speeds, 67 W, 5.8 lb
Paired with a 20×20 MERV 13 filter it can form the DIY air cleaner EPA studied; check for a UL or ETL safety mark before building one.
It is our DIY base pick.
Filtrete 20x25x1 Air Filter, MERV 13, MPR 1900, 2-Pack
3Filtrete MPR 1900 is a MERV 13 HVAC filter that traps fine allergens as air moves through your furnace or AC.
👍 Pros & Cons
Pros
- Filters the whole house through HVAC
- MERV 13 rating
- Trusted 3M brand
Cons
- Only works while the fan runs
- Check your system can handle MERV 13
📄 Detailed Review
- Type: MERV 13 furnace / AC filter
- Fits: 20x25x1 HVAC returns (other sizes sold)
- Key feature: Captures fine allergens in the HVAC system
It works whenever the system fan runs, so setting the fan to On increases filtration.
Check your system manual before moving to a higher MERV rating.
Levoit Core 300-P Smoke Remover Replacement Filter
4Levoit’s Smoke Remover filter is a genuine 4-stage filter for the Core 300-P and 300S-P.
👍 Pros & Cons
Pros
- Genuine Levoit fit
- Dual-sided pre-filter for ash
- Two spare pre-filters included
Cons
- Core 300-P and 300S-P only
📄 Detailed Review
- Type: Genuine smoke filter
- Includes: 1 filter + 2 pre-filters
- Key feature: 4-stage, with 2 extra dual-sided pre-filters
Levoit says its dual-sided pre-filter is more effective against wildfire ash, and two spare replaceable pre-filters come in the box.
It is our smoke-season filter pick.
Check Levoit Core 300-P Smoke Remover Filter Price on Amazon
16 x 48 Inch Cut-to-Fit Carbon Filter Sheet
5This 16 x 48 inch carbon sheet is 1/8 inch thick and cuts to size for purifiers and other appliances.
👍 Pros & Cons
Pros
- Cuts to fit many purifiers
- Adds odor control
- Protects the main filter from large dust
Cons
- Thin compared with a deep carbon bed
📄 Detailed Review
- Type: Cut-to-fit carbon pre-filter
- Includes: 1 sheet
- Key feature: 16 x 48 x 1/8 in
The maker suggests cleaning it about once a month with a soft brush or vacuum.
It is our universal carbon pick.
Check Cut-to-Fit Carbon Filter Sheet, 16 x 48 in Price on Amazon
How We Chose the Best Alternative to Air Purifier for Wildfire Smoke
To choose the best alternative to air purifier for wildfire smoke, we compared popular HEPA purifiers, DIY box fan parts and smoke filters on Amazon by smoke CADR, coverage and owner feedback.
EPA found a box fan with a MERV 13 filter cuts indoor smoke and that filters must be changed often during smoke events; see the EPA research on DIY air cleaners for wildfire smoke.
Product details in this guide are based on manufacturer specifications and verified owner feedback. Read more on our How We Test page.
Buying Guide: Choosing an Alternative
Keep these points in mind before you buy.
DIY box fan air cleaners
EPA testing found a box fan with one 1-inch MERV 13 filter reached a smoke CADR of about 111; adding a cardboard shroud raised it to 156, and a four-filter Corsi-Rosenthal box reached about 401.
Box fan safety
EPA recommends newer box fans made in 2012 or later with a UL or ETL safety mark, no extension cord, and working smoke detectors in the home.
Upgrade the HVAC filter
A MERV 13 furnace filter cleans air for the whole home whenever the system fan runs. Check that your system can handle the higher rating.
Change filters during smoke
EPA found DIY air cleaners were almost ineffective with dirty filters. Check filters daily during smoke and replace them when they turn dark or smell like smoke.
DIY Safety Tips
Build it safely:
- Use a 2012 or newer box fan.
- Look for a UL or ETL mark.
- Skip extension cords.
- Never block both sides.
Quick answers about the best alternative to air purifier for wildfire smoke.
- 2012+ box fan
- UL or ETL mark
- No extension cords
- Never block both sides
Frequently Asked Questions
What is the best alternative to air purifier for wildfire smoke?
The best alternative to air purifier for wildfire smoke is a DIY box fan with MERV 13 filters, like BNX 20×20 filters on a 20-inch box fan, used with EPA’s safety tips.
Do DIY air cleaners work?
EPA found they can cut smoke, especially with a shroud and more filters.
Are they safe?
EPA and UL found no fire hazards in tests with newer fans, but follow safety tips.
Which filter should I use?
EPA recommends MERV 13.
How often should I change it?
When it looks dark or smells smoky, per EPA.
Final Verdict
Our final pick for the best alternative to air purifier for wildfire smoke is the BNX 20×20 MERV 13 Filters. Choose the Amazon Basics 20-Inch Box Fan if you want a fan to build on, or the Filtrete MERV 13 HVAC Filter for whole-home filtering through HVAC.
Related Guides
More air purifier guides:
- Best Air Purifier for Wildfire Smoke
- Best Affordable Air Purifier for Wildfire Smoke
- Best Air Purifier Replacement Filter 2026
- Best Air Purifier for Allergies
- Best Air Purifier for Large Room
Product details are based on manufacturer specifications at the time of writing. Prices and availability change often, so check Amazon for the latest price.
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