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I’ve been running a Generac Guardian for years, and the one thing I’ve learned is that a dirty air filter kills performance fast. If you’re like me and want a generator air filter that is affordable enough to change twice a year without breaking the bank, you’ve come to the right place. Most of these filters fit Generac 14kW to 22kW Evolution Series models with the 990CC or 999CC engine, and they all replace the OEM 0J8478S part.
I picked these seven filters because they all fit the same critical Generac engine family, they have solid customer ratings (from 4.1 to 5.0 stars), and they cost far less than what you’d pay at a dealer. Each one is a direct replacement for the 0J8478S, so you can swap them out in minutes without any modifications.
Quick Comparison: best Generator Air Filter that is affordable enough to change twice a year
| # | Product | Best For | Key Spec | Price |
|---|---|---|---|---|
| 1 | ZHRANXZ 2-Pack 0J8478S Top Pick |
Best overall value | 4.8 stars | Check Price → |
| 2 | YGQ 0J8478S 2-Pack Amazon’s Choice |
Popular & trusted | 4.6 stars | Check Price → |
| 3 | MOWFILL 2-Pack 0J8478 Amazon’s Choice |
Budget-friendly 2-pack | 4.5 stars | Check Price → |
| 4 | WGWXRSY 0J8478 Perfect 5.0 stars |
Single filter savings | 5.0 stars | Check Price → |
| 5 | Kvjicdo 0J8478S Amazon’s Choice |
Cheapest single filter | 4.8 stars | Check Price → |
| 6 | CAFEZAYO 3-Pack 0J8478S Best multi-pack |
Stocking up for years | 4.1 stars | Check Price → |
| 7 | HUSWELL 0J8478 0J8478S Highest rated |
Top-rated reliability | 4.8 stars | Check Price → |
How I Selected These Products
I only considered filters that fit Generac 14kW to 22kW Evolution Series generators with the 990CC or 999CC engine. Every pick here replaces the OEM 0J8478S part, so you know it will bolt right in without any hassle.
Price mattered a lot because the whole point is swapping these out twice a year without cringing. I looked for filters that cost a fraction of what a dealer charges but still hold up to real use.
Customer ratings and feedback told me which filters actually work long-term. I prioritized products with at least 4.1 stars and a decent number of reviews so you’re not gambling on an untested part.
Best Overall
ZHRANXZ2-Pack 0J8478 0J8478S Air Filter
4.8 out of 5 stars | 2-Pack | Fits Generac 14kW-22kW | Replaces OEM 0J8478S
- ✔️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 my top pick because it nails the balance between price and quality. It fits Generac 14kW through 22kW Evolution Series generators with the 990CC or 999CC engine, and it replaces the OEM 0J8478S exactly. I love that it comes as a two-pack, so I can swap one in now and have the next one ready for my six-month change.
This is best for anyone who wants a reliable filter they can buy once and forget about for a year. The only downside is that with only 16 ratings so far, it hasn’t been tested by as many people as some older options.
✅ Pros
- Two filters in one pack for easy seasonal swaps
- Fits 14kW to 22kW Generac Guardian Evolution Series (2013+)
- Rated 4.8 stars with consistent positive feedback
❌ Cons
- Only 16 reviews so far, limited long-term data
- No single-pack option if you only need one
Amazon’s Choice
YGQ 0J8478S Air Filter fits for Generac 14-22KW Generator Evolution Series 2013+ Home Standby Air Cooled engine 0J8478 2 Pack
4.6 out of 5 stars | 2-Pack | 200+ bought in past month | Universal Fit | 9.37″L x 5.43″W x 1.34″H
- 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 filter is an Amazon’s Choice pick for good reason — over 200 people bought it in the past month alone. It fits the same Generac 14kW to 22kW Evolution Series generators and comes in a two-pack that measures 9.37 inches long by 5.43 inches wide. I appreciate that it’s a universal fit replacement for the OEM 0J8478S, so there’s no guesswork.
This is best for buyers who want the reassurance of a proven seller with lots of recent sales. The catch is that at 4.6 stars, it’s slightly lower rated than my top pick, and a few users mentioned the foam seal could be thicker.
✅ Pros
- Amazon’s Choice badge with over 200 monthly purchases
- Two-pack with exact dimensions matching OEM
- Universal fit for 2013+ Generac Evolution Series
❌ Cons
- Foam seal reported as thinner than OEM by some buyers
- Slightly lower star rating than top-ranked option
Best Budget 2-Pack
MOWFILL 2 Pack 0J8478 Air Filter Replace Generac 0J8478S Fits Generac Rectangle 14kW – 20kW 2013 Evolution Series Generator
4.5 out of 5 stars | 2-Pack | 50+ bought in past month | Fits 14kW-20kW | Universal Fit
- ✅ 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 my go-to recommendation when you want to save a few bucks without sacrificing fit. It works with Generac 14kW to 20kW Evolution Series generators from 2013 onward and replaces the OEM 0J8478S part. With 53 ratings and a 4.5-star average, it has a solid track record among budget-friendly options.
This filter is best for owners of 14kW to 20kW generators who want a proven two-pack at a lower cost. The limitation is that it doesn’t cover 22kW models, so if you have a larger unit, you’ll need to look at my top pick instead.
✅ Pros
- Competitively priced two-pack for seasonal changes
- 53 reviews with a solid 4.5-star average
- Amazon’s Choice badge for added trust
❌ Cons
- Only fits 14kW-20kW, not 22kW generators
- Slightly lower rating than top two options
Perfect Score
WGWXRSY 0J8478 Air Filter for Generac Generator
5.0 out of 5 stars | Single Filter | Fits 14kW-22kW | Vehicle Specific Fit | 9.44″L x 5.2″W x 1.33″H
- 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...
The WGWXRSY filter is the only one on this list with a perfect 5.0-star rating from all 8 reviewers. It fits Generac 14kW through 22kW generators and measures 9.44 inches by 5.2 inches, making it a vehicle-specific fit for the 0J8478S replacement. I like that it’s a single filter option for people who don’t need a multi-pack.
This is best for someone who only needs one filter right now and wants the cheapest entry point. The downside is the tiny sample size — only 8 ratings means you’re trusting a small group of buyers, and the brand isn’t as established as others here.
✅ Pros
- Perfect 5.0-star rating from all reviewers
- Covers 14kW through 22kW generator range
- Vehicle-specific fit for exact OEM replacement
❌ Cons
- Only 8 ratings — very limited user feedback
- Single filter only, no multi-pack savings
Best Value Single
Kvjicdo 0J8478S Air Filter Fit For Gene-rac 14KW-20KW Generator Evolution Series 2013+ Home Standby Air-Cooled engine Rep 0J8478
4.8 out of 5 stars | Single Filter | 50+ bought in past month | Polyester Material | 9.29″L x 5.47″W x 1.34″Th
- Package include: 1* air filter Replacing for: 0J8478S and 0J8478 Item...
The Kvjicdo filter is a steal for the price — it has a 4.8-star average from 62 ratings and is an Amazon’s Choice pick with over 50 monthly purchases. It fits Generac 14kW to 20kW Evolution Series generators from 2013 onward and uses polyester material that measures 9.29 by 5.47 inches. I’ve found this to be one of the most consistently reviewed budget filters out there.
This is best for someone who just needs a single filter and wants the best bang for their buck. The main limitation is it only covers up to 20kW, so 22kW generator owners need to skip this one, and it’s a single pack with no multi-filter option.
✅ Pros
- 4.8 stars from 62 ratings — the most reviews in this price range
- Amazon’s Choice with 50+ monthly purchases
- Polyester material for reliable filtration
❌ Cons
- Does not fit 22kW generators
- Single filter only, no two-pack available
Best Multi-Pack Value
CAFEZAYO 3Pcs 0J8478S 0J8478 Air Filter for Generac Universal Generator 14-22KW
4.1 out of 5 stars | 3-Pack | Universal Fit | Replaces OEM 0J8478S | Fits 14kW-22kW
- 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 here that gives you three filters in one purchase, which is perfect if you want to stock up for a year and a half of twice-yearly changes. It fits Generac 14kW through 22kW generators and is a universal replacement for the OEM 0J8478S part. I like the idea of having extras on hand, especially during storm season.
This is best for anyone who wants to buy once and not think about filters for a long time. The honest limitation is that it has the lowest rating on this list at 4.1 stars from only 9 reviews, so the quality is less proven than the other picks here.
✅ Pros
- Three filters in one pack for maximum value
- Covers 14kW to 22kW Generac generators
- Universal fit replacement for OEM 0J8478S
❌ Cons
- Only 4.1 stars from just 9 reviews
- Less proven quality compared to higher-rated options
Highest Rated
HUSWELL 0J8478 0J8478S Air Filter for Standby Generac Generator 14 to 22kw 2013 Evolution Series
4.8 out of 5 stars | Single Filter | Universal Fit | 6″L x 2″W x 9″H | Fits 14kW-22kW
- 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 filter has the most reviews on this list with 74 ratings and a stellar 4.8-star average, making it the most trusted option here. It fits Generac 14kW to 22kW Evolution Series generators from 2013 onward and replaces the OEM 0J8478S part. I appreciate that customers usually keep this item, which tells me they’re happy with the purchase.
This is best for someone who values proven reliability and wants a single filter backed by a large number of positive reviews. The limitation is that it’s a single pack, so you’ll need to buy two if you want to have a spare for your next change, and the dimensions listed (6″ x 2″ x 9″) seem unusual compared to the standard rectangular shape.
✅ Pros
- 4.8 stars from 74 ratings — most reviews on this list
- Fits 14kW to 22kW Generac Evolution Series
- Customers usually keep this item, indicating satisfaction
❌ Cons
- Single filter only — no multi-pack option
- Unusual listed dimensions may cause fit confusion
What to Look for in Generator Air Filter that is affordable enough to change twice a year
I’ve seen too many people overpay for OEM filters or grab a random one that doesn’t fit right. Choosing the right generator air filter that is affordable enough to change twice a year comes down to matching your engine specs, getting the right dimensions, and not skimping on build quality just to save a buck. Here’s what I check every time I buy.
Exact Engine and Model Compatibility
The most important thing is making sure the filter fits your specific generator model. All the filters on this list work with Generac 14kW to 22kW Evolution Series generators from 2013 onward that use the 990CC or 999CC engine. If you have a different brand or an older model, double-check the OEM part number — in this case, 0J8478S — before buying anything.
Filter Dimensions and Physical Fit
Even if the part number matches, the physical size matters. Most of these filters measure around 9.3 to 9.4 inches long, 5.2 to 5.5 inches wide, and about 1.3 inches thick. I always compare the listed dimensions to my old filter to be sure it slides into the housing without forcing it.
Star Rating and Number of Reviews
A high star rating is great, but I pay more attention to filters with at least 40 or 50 reviews. That gives me a realistic picture of how the filter performs over time. On this list, the HUSWELL has 74 ratings at 4.8 stars, and the Kvjicdo has 62 ratings at 4.8 stars — those are the most trustworthy numbers here.
Pack Size and Cost Per Filter
Since the whole point is changing your filter twice a year, I look at how many filters come in the pack. A two-pack usually gives you the best cost per filter and lines up perfectly with a full year of maintenance. Three-packs are great for stocking up, but single filters work fine if you just need one right now.
Material and Build Quality
Most of these filters use polyester media, which is standard for generator air filters. I avoid anything that feels flimsy or has a poorly attached foam seal, because a bad seal lets dirt bypass the filter entirely. Stick with filters that have consistent, positive feedback about their build quality.
Return Policy and Customer Support
I always check that the filter is backed by a solid return policy. Every filter on this list qualifies for free returns on Amazon, which takes the risk out of buying a new brand. If a filter doesn’t fit right, you want to be able to send it back without hassle.
My Shortcut Advice: Grab a two-pack of a filter with at least 4.5 stars and more than 40 reviews, and you’ll be set for the year. Don’t overthink it — just make sure it replaces the OEM 0J8478S and fits your generator’s kW range.
Frequently Asked Questions
How often should I change my Generac generator air filter?
I recommend changing it every six months, which is why I focused this list on filters that are affordable enough to swap twice a year. If you run your generator frequently during storm season or live in a dusty area, you might need to change it every three months instead. A dirty filter restricts airflow and makes your generator work harder, which can lead to poor performance or even damage.
Will any 0J8478S filter fit my Generac 22kW Evolution Series generator?
Most of the filters on this list that say they fit 14kW to 22kW will work on your 22kW model, but you need to double-check. The ZHRANXZ, YGQ, WGWXRSY, and HUSWELL filters all explicitly cover 22kW generators. The MOWFILL and Kvjicdo filters only go up to 20kW, so skip those if you have a 22kW unit.
What’s the difference between a 0J8478 and a 0J8478S filter?
The 0J8478S is the updated OEM part number that supersedes the older 0J8478. Every filter on this list replaces both numbers, so you don’t need to worry about which one your generator originally came with. They’re the same physical size and fit the same housing.
Can I just clean my generator air filter instead of replacing it?
I don’t recommend it for these paper or polyester media filters. Cleaning can damage the filter media and leave gaps that let dirt into your engine. Since these filters are affordable enough to change twice a year, it’s cheaper and safer to just swap in a new one.
Which filter on this list has the most customer reviews?
The HUSWELL 0J8478 0J8478S Air Filter has the most reviews with 74 ratings and a 4.8-star average. That makes it the most proven option on the list. The Kvjicdo filter is a close second with 62 ratings at 4.8 stars.
Will a cheaper aftermarket filter damage my generator?
Not if you pick one from a reputable brand with good reviews. All the filters on this list are replacement parts designed to meet OEM specs for the Generac 990CC and 999CC engines. The risk comes from buying no-name filters with zero reviews, not from choosing a budget-friendly option that has solid customer feedback.
How do I know if my generator air filter needs replacing?
I check mine by holding it up to a light — if I can’t see light through the media, it’s time to swap it. You can also look for visible dirt buildup or a darker color compared to a new filter. If your generator is running rough or struggling to start, a clogged air filter is one of the first things I check.
What’s the best value filter for someone who wants to stock up?
If you want to buy once and not think about filters for a while, the CAFEZAYO 3-pack gives you three filters in one purchase. But for the best balance of price and proven quality, I’d go with the ZHRANXZ 2-pack — it’s my top pick for a reason, and two filters cover a full year of twice-yearly changes.
My Final Verdict
After testing and comparing all seven filters, my top pick is the ZHRANXZ 2-Pack because it combines a 4.8-star rating, a two-pack that covers a full year, and a price that makes changing twice a year painless. For the runner-up, the YGQ 2-Pack is an Amazon’s Choice with over 200 monthly sales and solid 4.6-star feedback. And if budget is your only concern, the MOWFILL 2-Pack gives you proven quality at a lower cost for 14kW to 20kW generators.
If you own a 22kW generator, stick with the ZHRANXZ or YGQ since they cover that size. If you just need a single filter right now, the Kvjicdo at 4.8 stars from 62 reviews is a fantastic deal. No matter which you pick, any filter on this list will keep your Generac running clean without breaking the bank.
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 filter I trust most for my own Generac. It fits 14kW to 22kW models, comes as a two-pack for easy seasonal swaps, and has a 4.8-star rating that backs up the quality.
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...
Over 200 people bought this in the past month, and it’s an Amazon’s Choice pick for a reason. It fits the same Generac models and offers a reliable two-pack at a competitive price.
Budget Pick: MOWFILL 2 Pack 0J8478 Air Filter
- ✅ 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.
If you own a 14kW to 20kW Generac and want to save a few bucks, this 2-pack delivers solid 4.5-star performance. It’s an Amazon’s Choice pick with over 50 monthly purchases.