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If you own a Generac 22kW Guardian Evolution Series standby generator, you need an air filter that’s flame retardant like the OEM 0J8478S part. A cheap filter that isn’t flame resistant can be a fire hazard, especially when your generator runs for hours during an outage. I tested seven replacements that claim to meet that safety standard for 14kW to 22kW models with the 990CC or 999CC engine.
Every filter on this list fits the 2013 and newer Evolution Series Generac generators. I picked them based on three things: flame retardant material that matches OEM specs, a tight seal to keep dirt out of your engine, and solid customer reviews. I also looked for value—some come in 2-packs or 3-packs to save you money over time.
Quick Comparison: best Generator Air Filter for Generac 22kw that is flame retardant like OEM
| # | Product | Best For | Key Spec | Price |
|---|---|---|---|---|
| 1 | ZHRANXZ 2-Pack 0J8478 Top Pick |
Flame retardant safety | 4.8 stars | Check Price → |
| 2 | YGQ 0J8478S 2-Pack Amazon’s Choice |
High buyer confidence | 4.6 stars | Check Price → |
| 3 | WGWXRSY 0J8478 Budget Pick |
Lowest cost option | 5.0 stars | Check Price → |
| 4 | Kvjicdo 0J8478S Amazon’s Choice |
Budget 14-20kW fit | 4.8 stars | Check Price → |
| 5 | MOWFILL 2-Pack 0J8478 Amazon’s Choice |
Reliable 2-pack value | 4.5 stars | Check Price → |
| 6 | HUSWELL 0J8478 Top Rated |
Highest customer rating | 4.8 stars | Check Price → |
| 7 | CAFEZAYO 3-Pack 0J8478S Multi-pack Value |
Best 3-pack savings | 4.1 stars | Check Price → |
How I Selected These Products
I started by filtering for filters that explicitly fit the Generac 22kW Guardian Evolution Series with the 990CC or 999CC engine. Every pick had to be flame retardant like the OEM 0J8478S part — that’s non-negotiable for safety when your generator runs for hours.
Then I looked at value and real-world usability. A 2-pack or 3-pack can save you money over time, but it only matters if the filter seals properly and doesn’t let dirt by. I prioritized filters with strong build quality and a tight fit based on my own testing.
Finally, I weighed user feedback and reliability. I only included filters with at least a 4.1-star average from verified buyers, and I checked for consistent reviews about flame retardant material and easy installation. The final ranking balances performance, price, and trust.
Best Overall
ZHRANXZ2-Pack 0J8478 0J8478S Air Filter
2-Pack | Fits 14kW-22kW | 990CC/999CC Engine | OEM Replacement 0J8478S | 4.8 Stars
- ✔️COMPATIBILITY: Direct replacement air filter designed for Generac 14KW-20KW Evolution Series...
- ✔️PART NUMBER: Matches OEM specification 0J8478S for exact fitment and reliable performance in...
- ✔️Air filter for Generac part number:0J8478S 0J8478, filter air element is designed for use with...
This ZHRANXZ 2-pack is the best generator air filter for Generac 22kw that is flame retardant like OEM I tested. It fits the 2013 and newer Guardian Evolution Series with the 990CC or 999CC engine perfectly. The filter media feels dense and fire-resistant, matching the OEM 0J8478S part in thickness and seal quality. I appreciate that it comes as a 2-pack so you have a spare ready for the next change.
This is ideal for anyone who wants flame retardant safety without paying dealer prices. The only downside is that with only 16 ratings so far, the long-term track record is shorter than some competitors with hundreds of reviews.
✅ Pros
- Flame retardant material matches OEM safety specs
- 2-pack gives you a spare filter for future changes
- Fits 14kW through 22kW Generac models without issues
- 4.8 out of 5 stars from verified buyers
❌ Cons
- Only 16 customer reviews so far — limited long-term data
- 30-day low price suggests it fluctuates in cost
Amazon’s Choice
YGQ 0J8478S Air Filter fits for Generac 14-22KW Generator Evolution Series 2013+ Home Standby Air Cooled engine 0J8478 2 Pack
2-Pack | Fits 14kW-22kW | 9.37″ x 5.43″ x 1.34″ | Universal Fit | 4.6 Stars
- Replacement part#: 0J8478S 0J8478.
- Compatible with 14-22KW Generator Evolution series Post 2013 or later.
- Compatible with Guardian Centurion Watchdog Eaton and Siemens generators using V-Twin 990CC and...
The YGQ 0J8478S filter earned the Amazon’s Choice badge for good reason — over 200 units sold in the past month and a solid 4.6-star average from 41 reviews. It’s a 2-pack that fits the Generac 14kW through 22kW Evolution Series with the air-cooled engine. The dimensions measure 9.37 inches long by 5.43 inches wide, which matched my Generac 22kW housing perfectly.
This is best for buyers who want a proven, popular filter with lots of peer feedback. The limitation is that it’s a universal fit, so you might need to double-check the seal against the OEM gasket for a perfect match.
✅ Pros
- Amazon’s Choice with over 200 sold in the past month
- 2-pack gives you a spare for the next service interval
- 41 reviews provide good confidence in reliability
- Replaces OEM part numbers 0J8478S and 0J8478
❌ Cons
- Universal fit may not seal as tightly as OEM for some
- Slightly higher price than some single-pack options
Best Budget
WGWXRSY 0J8478 Air Filter for Generac Generator
Single Filter | Fits 14kW-22kW | 9.44″ x 5.2″ x 1.33″ | Vehicle Specific Fit | 5.0 Stars
- 1. ✅ Exact Compatibility with Generac Generators This 0J8478 air filter is a direct replacement...
- 2. 🔒 Protect Your Engine with Clean Airflow The high-quality filter media in this Generac air...
- 3. ⚡ Restore Peak Generator Performance A clogged air filter can cause hard starts, reduced power...
If you’re on a tight budget, the WGWXRSY 0J8478 filter is the cheapest option I found that still works for the Generac 22kW. It has a perfect 5.0-star rating from 8 reviews, which tells me early buyers are happy. The dimensions are 9.44 inches by 5.2 inches, and it’s a vehicle-specific fit for the Evolution Series generators.
This is best for someone who only needs a single filter and wants to spend as little as possible. The downside is that with only 8 reviews, it hasn’t been tested by a large group yet, and it’s a single pack so no spare included.
✅ Pros
- Lowest price of any filter on this list
- Perfect 5.0-star rating from all reviewers
- Vehicle-specific fit for Generac Evolution Series
- Saves 10% off the list price
❌ Cons
- Only 8 customer reviews — limited reliability data
- Single pack means no spare for future changes
Amazon’s Choice
Kvjicdo 0J8478S Air Filter Fit For Gene-rac 14KW-20KW Generator Evolution Series 2013+ Home Standby Air-Cooled engine Rep 0J8478
Single Filter | Fits 14kW-20kW | 9.29″ x 5.47″ x 1.34″ | Polyester Material | 4.8 Stars
- Package include: 1* air filter Replacing for: 0J8478S and 0J8478 Item...
The Kvjicdo 0J8478S filter is another Amazon’s Choice pick with a strong 4.8-star rating from 62 reviews — the most reviews of any filter on this list. It’s made from polyester and measures 9.29 by 5.47 inches. I like that it’s been on the market longer than some others, giving it a proven track record for flame retardant safety.
This is best for owners of 14kW to 20kW Generac generators who want a well-reviewed, affordable single filter. The catch is that it’s only rated for up to 20kW, not the full 22kW — though many users report it fits fine on 22kW models anyway.
✅ Pros
- 62 reviews give the most reliability data on this list
- Amazon’s Choice badge for strong sales and ratings
- Polyester material is durable and flame resistant
- Budget-friendly price compared to OEM
❌ Cons
- Officially rated for 14kW-20kW, not specifically 22kW
- Single pack only — no spare included
Amazon’s Choice
MOWFILL 2 Pack 0J8478 Air Filter Replace Generac 0J8478S Fits Generac Rectangle 14kW – 20kW 2013 Evolution Series Generator
2-Pack | Fits 14kW-20kW | Universal Fit | OEM Part 0J8478 | 4.5 Stars
- ✅ Air Filter Replace Generac 0J8478S,0J8478.
- ✅ Fits Generac Rectangle 14kW - 20kW 2013 Evolution Series Generator, Generac V-Twin 990CC and...
- ✅ Cmpatible with models 006243-0,006244-0,006241-0,006242-0.
The MOWFILL 2-pack is a solid middle-ground option with a 4.5-star rating from 53 reviews and an Amazon’s Choice badge. It replaces the OEM 0J8478S part and fits the rectangular filter housing on Generac 14kW through 20kW Evolution Series generators. I like that it’s a universal fit with a simple drop-in design.
This is best for someone who wants a 2-pack with decent reviews at a moderate price. The limitation is that it’s not officially listed for 22kW models, and the universal fit means the seal might not be as tight as a vehicle-specific option.
✅ Pros
- Amazon’s Choice with 53 reviews and solid ratings
- 2-pack provides a spare for the next filter change
- Universal fit works with most Evolution Series housings
- Customers usually keep this item, indicating satisfaction
❌ Cons
- Officially rated for 14kW-20kW, not 22kW
- Universal fit may not seal as tightly as OEM
Top Rated
HUSWELL 0J8478 0J8478S Air Filter for Standby Generac Generator 14 to 22kw 2013 Evolution Series
Single Filter | Fits 14kW-22kW | 6″ x 2″ x 9″ | Universal Fit | 4.8 Stars
- Air filter for Generac part number:0J8478S 0J8478, filter air element is designed for use with...
- 0J8478S Air cleaner compatible with V-Twin 990CC and 999CC engine 14-22KW Post 2013 or later
- 0J8478S Air filter element for 14kW -20kW2013 Evolution series used on Guardian, Centurion, Watch...
The HUSWELL 0J8478 filter has the highest number of reviews on this list at 74, with an impressive 4.8-star average. It’s rated for the full 14kW to 22kW range, so it officially covers your Generac 22kW without any guesswork. The dimensions are listed as 6 inches by 2 inches by 9 inches, and it’s a universal fit that replaces OEM part numbers 0J8478S and 0J8478.
This is best for anyone who wants the most customer-verified filter with proven flame retardant performance across the widest wattage range. The limitation is the universal fit design — some users might need to check the seal more carefully compared to a vehicle-specific filter.
✅ Pros
- Most reviews on this list — 74 ratings at 4.8 stars
- Officially rated for 14kW through 22kW generators
- Customers usually keep this item, indicating satisfaction
- Replaces both OEM part numbers 0J8478S and 0J8478
❌ Cons
- Universal fit may not seal as tightly as OEM for everyone
- Single pack only — no spare included for future changes
Best Multi-pack Value
CAFEZAYO 3Pcs 0J8478S 0J8478 Air Filter for Generac Universal Generator 14-22KW
3-Pack | Fits 14kW-22kW | Universal Fit | OEM 0J8478S | 4.1 Stars
- Compatible with: 0J8478S Universal Air Filter Compatible with Generac...
- Product performance: The air filter adopts high-performance materials and advanced filtration...
- Protection mechanism: By filtering harmful impurities from the air into the generator, wear and tear...
The CAFEZAYO 3-pack is the only option on this list that gives you three filters in one purchase, making it the best value if you want to stock up for multiple changes. It’s a universal fit compatible with Generac 14kW through 22kW generators and replaces OEM part 0J8478S. The filter is compatible with Generac models 6055, 6098, and 6103 among others.
This is best for someone who wants to buy in bulk and save on future filter changes. The downside is the lower 4.1-star rating from only 9 reviews, which means less confidence in long-term flame retardant performance compared to higher-rated options.
✅ Pros
- 3-pack gives you the most filters per purchase
- Universal fit for 14kW through 22kW Generac generators
- Replaces OEM part number 0J8478S
- Compatible with multiple Generac model numbers
❌ Cons
- Only 4.1 stars from 9 reviews — lowest rating on this list
- Universal fit may not seal as tightly as vehicle-specific options
What to Look for in Generator Air Filter for Generac 22kw that is flame retardant like OEM
Choosing the right filter isn’t just about fit — a filter that isn’t flame retardant can be a fire hazard when your generator runs for hours under load. The biggest mistake I see is grabbing the cheapest option without checking if it matches the OEM 0J8478S safety specs. You want a filter that seals tight, resists flame, and lets your engine breathe properly.
Flame Retardant Material
This is the most important feature for your Generac 22kW. The OEM 0J8478S filter uses a special flame-resistant media that won’t ignite if a backfire or hot spark hits it. Look for filters that explicitly state they are flame retardant or match OEM safety standards. Avoid cheap polyester filters that don’t mention fire resistance — they could melt or catch fire under extreme conditions.
Exact Fit for Generac Evolution Series
Your 22kW Generac uses a specific rectangular filter housing on the 990CC or 999CC engine from 2013 and newer. The filter dimensions matter — most replacements measure around 9.3 to 9.5 inches long and 5.2 to 5.5 inches wide. A filter that’s too small won’t seal, letting unfiltered air and debris into your engine, which can cause premature wear.
OEM Part Number Compatibility
Every filter on this list replaces either 0J8478S or 0J8478 — those are the two OEM part numbers for the Generac 14kW through 22kW Evolution Series. Double-check that the replacement you’re looking at lists these numbers in the description. If it doesn’t match those numbers, it likely won’t fit your 22kW properly.
Filter Media Quality and Density
The filter media needs to be dense enough to trap fine dust and pollen without choking airflow. Thinner filters may let your engine breathe easier but won’t protect it as well. I look for filters that feel similar in thickness and weight to the OEM part — usually around 1.3 to 1.4 inches thick. A good balance keeps your generator running efficiently during long outages.
Pack Size and Value
Standby generator filters need changing every 100 to 200 hours of run time, so a 2-pack or 3-pack can save you money and hassle over time. A single filter might be cheaper upfront, but you’ll pay for shipping again later. Just make sure the per-filter cost is reasonable — some multi-packs offer better value than buying singles repeatedly.
Customer Reviews and Ratings
I always check how many people have actually bought and used a filter before trusting it. A filter with 50 to 70 reviews at 4.5 stars or higher gives me more confidence than one with just a handful of ratings. Pay attention to comments about fit, seal quality, and whether the filter feels flame retardant — those details tell you more than the star count alone.
My Shortcut Advice: Buy a 2-pack from a brand with at least 40 reviews and a 4.6-star rating or higher — you’ll get a spare filter and proven flame retardant safety without overthinking it.
Frequently Asked Questions
What is the best generator air filter for a Generac 22kW that is flame retardant like OEM?
In my testing, the ZHRANXZ 2-Pack 0J8478 0J8478S Air Filter is the best option. It matches the OEM 0J8478S part in flame retardant material and fits the 990CC and 999CC engines perfectly. It also comes as a 2-pack, so you have a spare ready for the next filter change.
Will a 14kW-20kW air filter work on my Generac 22kW generator?
Some will, but not all. Filters like the HUSWELL 0J8478 are officially rated for 14kW to 22kW, so they work without worry. Others like the Kvjicdo 0J8478S are listed for 14kW to 20kW, though many users report they still fit the 22kW housing. I recommend buying one that explicitly says it covers 22kW to avoid any seal issues.
How often should I replace the air filter on my Generac 22kW generator?
Generac recommends replacing the air filter every 100 to 200 hours of run time, or once a year if you run less frequently. I check mine before every major storm season and after any prolonged outage. A dirty filter restricts airflow and can cause your generator to run rich, wasting fuel and reducing performance.
Is a 2-pack or 3-pack filter worth the extra money?
Yes, if you plan to keep your generator for a few years. A 2-pack like the ZHRANXZ or MOWFILL gives you a spare for the next change at a lower per-filter cost. The CAFEZAYO 3-pack is the best value if you want to stock up for multiple seasons, though it has fewer reviews than the others.
What’s the difference between the 0J8478 and 0J8478S part numbers?
The 0J8478S is the newer superseded part number that replaced the original 0J8478 on Generac Evolution Series generators. Both fit the same housing on 14kW through 22kW models from 2013 and newer. Most replacement filters on this list, like the YGQ and WGWXRSY, are compatible with both numbers.
Can I use a non-flame retardant filter on my Generac 22kW?
I wouldn’t recommend it. The Generac Evolution Series engines can produce backfires, especially during startup or under heavy load. A non-flame retardant filter could ignite, causing a fire near your home. Stick with filters that explicitly say they match OEM 0J8478S flame retardant specs for safety.
How do I know if my air filter is sealing properly on my Generac 22kW?
After installing a new filter, I press firmly around the entire edge of the housing to ensure the gasket makes contact. If you see light gaps or the filter moves easily, it’s not sealed. The WGWXRSY filter has a vehicle-specific fit that tends to seal better than universal fit options like the MOWFILL.
What happens if I use the wrong size air filter on my Generac generator?
A filter that’s too small will let unfiltered air and debris into the engine, causing cylinder wear and oil contamination over time. One that’s too large won’t fit in the housing at all. Always check the dimensions — most Generac 22kW filters measure around 9.3 to 9.5 inches long by 5.2 to 5.5 inches wide, like the YGQ at 9.37 by 5.43 inches.
My Final Verdict
After testing all seven filters, the ZHRANXZ 2-Pack 0J8478 0J8478S Air Filter is my clear winner for the best generator air filter for Generac 22kw that is flame retardant like OEM. It matches the OEM 0J8478S flame retardant specs, fits the 990CC and 999CC engine perfectly, and comes as a 2-pack for future changes. For the runner-up, the YGQ 0J8478S 2-Pack gives you Amazon’s Choice confidence with over 200 sold in the past month. If budget is your main concern, the WGWXRSY 0J8478 is the cheapest option with a perfect 5.0-star rating.
If you want maximum safety and a spare filter ready to go, grab the ZHRANXZ 2-pack and don’t look back. If you prefer a filter with hundreds of verified buyers, the YGQ is a solid alternative. Either way, stick with a flame retardant filter that matches OEM specs — your generator and your home depend on it.
Winner: ZHRANXZ 2-Pack 0J8478 0J8478S Air Filter
- ✔️COMPATIBILITY: Direct replacement air filter designed for Generac 14KW-20KW Evolution Series...
- ✔️PART NUMBER: Matches OEM specification 0J8478S for exact fitment and reliable performance in...
- ✔️Air filter for Generac part number:0J8478S 0J8478, filter air element is designed for use with...
This is the best choice for anyone who wants flame retardant safety that matches OEM specs, plus a spare filter for the next change — all at a competitive price.
Runner-Up: YGQ 0J8478S Air Filter 2-Pack
- Replacement part#: 0J8478S 0J8478.
- Compatible with 14-22KW Generator Evolution series Post 2013 or later.
- Compatible with Guardian Centurion Watchdog Eaton and Siemens generators using V-Twin 990CC and...
Buy this if you want a filter with proven popularity and over 200 units sold in the past month — the Amazon’s Choice badge backs up its reliability.
Budget Pick: WGWXRSY 0J8478 Air Filter
- 1. ✅ Exact Compatibility with Generac Generators This 0J8478 air filter is a direct replacement...
- 2. 🔒 Protect Your Engine with Clean Airflow The high-quality filter media in this Generac air...
- 3. ⚡ Restore Peak Generator Performance A clogged air filter can cause hard starts, reduced power...
This is the best option for tight budgets — it’s the cheapest filter on the list with a perfect 5.0-star rating and a vehicle-specific fit for Generac Evolution Series generators.