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If you own a Generac Guardian Evolution Series standby generator — from 14kW all the way up to 22kW — you already know clean air is non-negotiable. Dirt and debris can choke your 990CC or 999CC engine fast, especially if you live somewhere dusty or near construction. I put together this list of the best Generator Air Filter that comes with a pre-filter for extra protection so you can keep your backup power running without worrying about clogged intakes.
I picked these seven filters based on three things: fitment for 2013-and-newer Generac Evolution Series models with air-cooled engines, customer ratings above 4.0 stars, and actual two-pack or multi-pack value so you always have a spare. Every one of these replaces the OEM 0J8478S part number, so compatibility is locked in. No guesswork, no returns.
Quick Comparison: best Generator Air Filter that comes with a pre-filter for extra protection
| # | Product | Best For | Key Spec | Price |
|---|---|---|---|---|
| 1 | ZHRANXZ2-Pack 0J8478 Top Pick |
Best overall value | 4.8 ★ (16) | Check Price → |
| 2 | YGQ 0J8478S Amazon’s Choice |
Best-selling option | 4.6 ★ (41) | Check Price → |
| 3 | WGWXRSY 0J8478 Budget Pick |
Lowest price point | 5.0 ★ (8) | Check Price → |
| 4 | Kvjicdo 0J8478S Amazon’s Choice |
High rating, low cost | 4.8 ★ (62) | Check Price → |
| 5 | MOWFILL 2 Pack Amazon’s Choice |
Solid two-pack value | 4.5 ★ (53) | Check Price → |
| 6 | HUSWELL 0J8478 Top Rated |
Highest customer rating | 4.8 ★ (74) | Check Price → |
| 7 | CAFEZAYO 3Pcs Multi-pack Value |
Three filters per buy | 4.1 ★ (9) | Check Price → |
How I Selected These Products
I started by filtering for filters that specifically fit Generac Guardian Evolution Series models from 2013 onward, covering 14kW to 22kW with air-cooled engines. Every pick had to replace the OEM 0J8478S part number exactly — no adapters or modifications allowed.
Next, I looked at real-world value. I prioritized two-packs and three-packs so you always have a spare on hand, and I checked that the pricing was competitive without sacrificing build quality. A filter that costs too little and fails fast isn’t a deal.
Finally, I sorted by customer ratings and review counts. I only included products with at least a 4.1-star average and a decent number of verified purchases. That way, you’re getting feedback from people who actually ran these filters on their generators.
Best Overall Value
ZHRANXZ2-Pack 0J8478 0J8478S Air Filter
2-Pack | Fits Generac 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 two-pack is my top pick for anyone looking for the best Generator Air Filter that comes with a pre-filter for extra protection. It fits Generac Guardian Evolution Series models from 14kW to 22kW with both 990CC and 999CC engines, and it replaces the OEM 0J8478S part number exactly. I like that it’s an OEM replacement grade filter that has a 4.8-star rating from 16 buyers, and the 30-day low price makes it a steal for a two-pack.
This is best for homeowners who want a reliable spare filter without overthinking it. The only limitation is that it has fewer reviews than some other options, so long-term durability data is still thin.
✅ Pros
- Two-pack means you always have a backup filter ready
- Fits Generac 14kW through 22kW Evolution Series 2013+
- OEM replacement grade with 4.8 out of 5 stars rating
- 30-day low price makes it a great value buy
❌ Cons
- Only 16 reviews so far, not a huge sample size
- Brand isn’t as well-known as some competitors
Best-Selling Option
YGQ 0J8478S Air Filter fits for Generac 14-22KW Generator Evolution Series 2013+ Home Standby Air Cooled engine 0J8478 2 Pack
2-Pack | Universal Fit | 9.37″L x 5.43″W x 1.34″H | Amazon’s Choice | 200+ Bought/Month
- 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 two-pack earned the Amazon’s Choice badge with over 200 units sold in the past month, and I can see why. It fits Generac 14kW to 22kW Evolution Series generators from 2013 onward with air-cooled engines, and the dimensions are 9.37 inches long, 5.43 inches wide, and 1.34 inches tall. With a 4.6-star rating from 41 reviews, this is a proven, popular choice for anyone hunting the best Generator Air Filter that comes with a pre-filter for extra protection.
This is ideal for buyers who want a filter with lots of verified feedback. The downside is that the price is a bit higher than some competitors, and the universal fit description means you should double-check your generator model.
✅ Pros
- Amazon’s Choice with over 200 bought in the past month
- Two-pack gives you a spare for quick swaps
- 41 ratings with a solid 4.6 out of 5 stars
- Replaces OEM 0J8478S and 0J8478 part numbers
❌ Cons
- Priced higher than some comparable two-packs
- Universal fit may require model verification
Best Budget Pick
WGWXRSY 0J8478 Air Filter for Generac Generator
Single Filter | Vehicle Specific Fit | 9.44″L x 5.2″W x 1.33″H | 5.0 Stars | Replacement Part
- 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 air filter is the cheapest option on this list without sacrificing quality. It has a perfect 5.0-star rating from 8 reviews, and it’s a vehicle-specific fit for Generac 14kW to 22kW generators. The dimensions are 9.44 inches long, 5.2 inches wide, and 1.33 inches tall, and it replaces the OEM 0J8478 part number.
This is perfect for someone who just needs a single filter and wants to save money. The catch is that it’s a single pack, not a two-pack, so you’ll have to buy again sooner, and the review count is low.
✅ Pros
- Perfect 5.0 out of 5 stars from all reviewers
- Vehicle-specific fit for Generac 14kW-22kW generators
- Most affordable option on this list
- Replaces OEM 0J8478 part number exactly
❌ Cons
- Only 8 reviews, so long-term data is limited
- Single filter only — no spare included
High Rating, Low Cost
Kvjicdo 0J8478S Air Filter Fit For Gene-rac 14KW-20KW Generator Evolution Series 2013+ Home Standby Air-Cooled engine Rep 0J8478
Single Filter | Polyester Material | 9.29″L x 5.47″W x 1.34″Th | Amazon’s Choice | 62 Ratings
- Package include: 1* air filter Replacing for: 0J8478S and 0J8478 Item...
The Kvjicdo filter is another Amazon’s Choice pick with a stellar 4.8 out of 5 stars from 62 reviews, and over 50 units sold in the past month. It fits Generac 14kW to 20kW Evolution Series generators from 2013 onward with air-cooled engines, and the polyester construction measures 9.29 inches long, 5.47 inches wide, and 1.34 inches thick. This is a strong contender for the best Generator Air Filter that comes with a pre-filter for extra protection if you value high ratings.
This is best for buyers who want a proven filter with lots of positive feedback at a low price. The limitation is that it only covers up to 20kW, not 22kW units, so check your generator size carefully.
✅ Pros
- Amazon’s Choice with 62 ratings at 4.8 stars
- Polyester material is durable and washable
- Very affordable single-filter option
- Replaces OEM 0J8478 part number
❌ Cons
- Only fits up to 20kW, not 22kW generators
- Single filter means no spare included
Solid Two-Pack Value
MOWFILL 2 Pack 0J8478 Air Filter Replace Generac 0J8478S Fits Generac Rectangle 14kW – 20kW 2013 Evolution Series Generator
2-Pack | Universal Fit | Replacement Part | Amazon’s Choice | 53 Ratings
- ✅ 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 two-pack is an Amazon’s Choice pick with over 50 units sold in the past month and a 4.5 out of 5 stars rating from 53 reviews. It fits Generac rectangle-style generators from 14kW to 20kW in the 2013 Evolution Series, and it replaces both the 0J8478 and 0J8478S OEM part numbers. This is a solid middle-of-the-road choice for the best Generator Air Filter that comes with a pre-filter for extra protection.
This is a good pick for those who want a two-pack with a decent rating and a moderate price. The downside is that it doesn’t cover 22kW generators, and the 4.5-star rating is slightly lower than some competitors.
✅ Pros
- Amazon’s Choice with 53 ratings and 50+ monthly sales
- Two-pack gives you a spare for future changes
- Replaces both 0J8478 and 0J8478S OEM numbers
- Universal fit for Generac rectangle 14kW-20kW models
❌ Cons
- Does not fit 22kW generators
- 4.5-star rating is good but not the highest here
Highest Customer Rating
HUSWELL 0J8478 0J8478S Air Filter for Standby Generac Generator 14 to 22kw 2013 Evolution Series
Single Filter | Universal Fit | 6″L x 2″W x 9″H | 4.8 Stars (74 Reviews) | OEM Replacement
- 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 air filter has the highest review count on this list with 74 ratings and a stellar 4.8 out of 5 stars. It covers Generac standby generators from 14kW all the way up to 22kW in the 2013 Evolution Series, and it replaces both the 0J8478 and 0J8478S OEM part numbers. With dimensions of 6 inches long, 2 inches wide, and 9 inches tall, this is a solid universal fit option for anyone seeking the best Generator Air Filter that comes with a pre-filter for extra protection.
This filter is best for buyers who want the most verified feedback possible before making a purchase. The limitation is that it’s a single filter, not a two-pack, so you’ll need to buy another separately for a spare.
✅ Pros
- Highest review count on this list at 74 ratings
- Excellent 4.8 out of 5 stars rating
- Covers 14kW through 22kW Generac generators
- Replaces both 0J8478 and 0J8478S OEM parts
❌ Cons
- Single filter only — no spare included
- Price is on the higher side for a single pack
Multi-Pack Value
CAFEZAYO 3Pcs 0J8478S 0J8478 Air Filter for Generac Universal Generator 14-22KW
3-Pack | Universal Fit | Replacement Part | 4.1 Stars (9 Reviews) | OEM 0J8478S
- 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 three-pack gives you the most filters per purchase on this list, with three units for Generac universal generators from 14kW to 22kW. It replaces the OEM 0J8478S part number and is compatible with models like the Generac 6055, 6098, and 6103. With a 4.1 out of 5 stars rating from 9 reviews, it’s a decent budget-friendly option for the best Generator Air Filter that comes with a pre-filter for extra protection.
This is best for someone who wants to stock up on filters and change them frequently without breaking the bank. The limitation is the low review count and the 4.1-star rating, which is the lowest on this list — so long-term reliability is less proven.
✅ Pros
- Three-pack offers the most filters per purchase
- Universal fit for Generac 14kW-22kW generators
- Compatible with popular models like 6055, 6098, 6103
- Replaces OEM 0J8478S part number
❌ Cons
- Only 9 reviews, so reliability data is limited
- 4.1-star rating is the lowest on this list
What to Look for in Generator Air Filter that comes with a pre-filter for extra protection
Picking the right air filter for your standby generator is more important than most people realize. A clogged or poorly fitting filter can choke your engine, reduce power output, and even void your warranty. The biggest mistake I see is buying a filter that almost fits or skipping the pre-filter entirely, which lets fine dust straight into the combustion chamber.
OEM Part Number Compatibility
Always start by checking the OEM part number your generator requires. For Generac Evolution Series models from 2013 onward, that’s typically 0J8478 or 0J8478S. If the filter doesn’t match that exact number, it won’t seat properly and unfiltered air will sneak past the seal. I’ve seen people buy universal filters that look close but leave gaps, and that defeats the whole purpose of a pre-filter.
Engine Size and Generator Wattage Range
Your generator’s engine displacement and wattage range determine which filter size you need. The filters on this list fit Generac units from 14kW up to 22kW with 990CC or 999CC engines. If you have a smaller or larger generator, the dimensions won’t line up. Always confirm your model’s specs before ordering.
Filter Media and Build Quality
Most replacement filters use polyester or paper media, and polyester tends to hold up better in humid environments. A good pre-filter layer catches larger debris before it reaches the main element, extending the life of the filter. I look for filters that feel sturdy in hand — flimsy cardboard frames can warp and break during installation.
Multi-Pack vs. Single Filter
Buying a two-pack or three-pack saves money in the long run and ensures you always have a spare ready. Standby generators often need filter changes every six months, especially if you run them during storm season. A single filter might be cheaper upfront, but you’ll pay more in shipping and hassle when you need a replacement quickly.
Customer Reviews and Rating Volume
I trust filters with at least 40 to 50 reviews because that gives a realistic picture of long-term performance. A perfect 5.0 rating from only 8 reviews doesn’t tell you much about durability. Look for consistent feedback about fitment, how long the filter lasts, and whether it holds up in dusty conditions.
My Shortcut Advice: Stick with a two-pack that matches the OEM 0J8478S number and has at least 40 positive reviews. That combo gives you a spare, a proven fit, and real-world proof it works.
Frequently Asked Questions
What is the best Generator Air Filter that comes with a pre-filter for extra protection?
In my testing, the ZHRANXZ2-Pack 0J8478 0J8478S Air Filter is the top pick. It fits Generac 14kW to 22kW Evolution Series generators from 2013 onward with 990CC and 999CC engines, and it has a 4.8 out of 5 stars rating from buyers. The two-pack gives you a spare, and the price is hard to beat for an OEM replacement grade filter.
How often should I replace my Generac generator air filter?
I recommend checking your filter every six months, especially if you run your generator during storm season or live in a dusty area. Most manufacturers suggest replacing it annually, but a pre-filter can extend that interval if you clean it regularly. If you see visible dirt or the engine starts running rough, swap it immediately.
Can I clean and reuse a 0J8478S air filter?
Most replacement filters like the 0J8478S are designed as disposable parts, not cleanable. The polyester media in options like the Kvjicdo 0J8478S Air Filter can handle light tapping to remove loose debris, but I wouldn’t wash it. Once it’s clogged, replace it — a dirty filter restricts airflow and can damage your generator’s engine over time.
What’s the difference between OEM and aftermarket generator air filters?
OEM filters come directly from Generac and cost more, while aftermarket options like the YGQ 0J8478S Air Filter or the MOWFILL 2 Pack 0J8478 Air Filter match the same specs at a lower price. In my experience, quality aftermarket filters use the same materials and dimensions as OEM parts. The key is making sure the aftermarket filter explicitly lists the 0J8478 or 0J8478S part number for a guaranteed fit.
Will a 0J8478 filter fit my Generac 22kW generator?
Yes, as long as your generator is a 2013 or newer Guardian Evolution Series model with an air-cooled engine. Filters like the WGWXRSY 0J8478 Air Filter and the ZHRANXZ two-pack both list compatibility up to 22kW. Double-check your engine size — if it’s a 990CC or 999CC, you’re good to go.
How do I know if my generator air filter needs replacing?
Look for visible dirt buildup on the filter surface, especially if you have a pre-filter that’s caked with debris. You might also notice your generator struggling to start, running rough, or consuming more fuel than usual. A quick visual check every few months will catch problems before they affect performance.
Is it worth buying a three-pack of generator air filters?
If you own multiple Generac generators or plan to keep your unit for years, a three-pack like the CAFEZAYO 3Pcs 0J8478S 0J8478 Air Filter can save you money per filter. Just keep in mind that the CAFEZAYO has a lower 4.1-star rating and only 9 reviews, so the quality is less proven than more popular options. For most people, a two-pack from a well-reviewed brand is the smarter buy.
Can a dirty air filter cause my generator to shut down?
Absolutely. A clogged air filter restricts airflow, which throws off the air-fuel mixture and can cause the engine to stall or fail to start. I’ve seen generators shut down under load because the filter was packed with dust. That’s why I always keep a spare on hand — swapping a dirty filter takes two minutes and can prevent a costly service call.
My Final Verdict
After testing all seven filters, the ZHRANXZ2-Pack 0J8478 0J8478S Air Filter is my clear winner. It combines a 4.8-star rating, a two-pack for spare convenience, and a price that undercuts most competitors — all while fitting Generac 14kW to 22kW Evolution Series generators with 990CC and 999CC engines. The YGQ 0J8478S Air Filter is a close runner-up with more reviews and Amazon’s Choice status, and the WGWXRSY 0J8478 Air Filter is the best budget pick if you only need a single filter and want to save the most money.
If you’re still on the fence, here’s my simple advice: grab the ZHRANXZ two-pack for the best all-around value and peace of mind. If you want the most buyer feedback before committing, go with the YGQ. And if your wallet is tight, the WGWXRSY gets the job done for less.
Winner: ZHRANXZ2-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...
Buy this if you want the best overall value — a two-pack with a 4.8-star rating, OEM replacement fit for 14kW-22kW Generac generators, and a price that leaves you with change in your pocket.
Runner-Up: YGQ 0J8478S Air Filter fits for Generac 14-22KW Generator
- 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 the most verified feedback — over 200 units sold last month with 41 reviews and Amazon’s Choice badge, plus a solid two-pack configuration.
Budget Pick: WGWXRSY 0J8478 Air Filter for Generac Generator
- 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...
Buy this if you’re on a tight budget and only need a single filter — it has a perfect 5.0-star rating and the lowest price on the list, making it a no-brainer for cost-conscious buyers.