Start With the 33268, Then Compare
I'm a quality compliance manager at an HVAC parts distributor in the Midwest. I review every Tecumseh 33268 air filter that goes through our warehouse—roughly 600 units a week. I've rejected around 5% of first deliveries in 2025 so far because the frame bowed or the gasket didn't sit flush. That's not a tiny number when you're protecting a compressor that costs $1,500 or more.
If you're handling commercial roof replacements Tecumseh, you probably already know about this filter. Roof work creates a lot of dust, and rooftop units sit right in that path. Once the old membrane comes off, the filter is the only thing standing between fine debris and your evaporator coil. A clogged or mis-seated 33268 means a poor cooling season and a possible compressor failure.
So when you order the 33268, you're really choosing between two categories: OEM Tecumseh or aftermarket. I'm going to compare them the same way I compare any two parts for a price book: fit, filtration media, total cost, and the maintenance context around the unit. I'd rather give you a framework than a one-word answer.
Before the numbers, one confession: I don't have hard data on industry-wide aftermarket defect rates. Based on our own receiving inspection over five years, my sense is that maybe 10 to 15% of first aftermarket deliveries have an issue you can see with a ruler. The big-name aftermarket suppliers are usually better than that. The cheap unbranded stuff is where the problems hide.
Fit and Seal: OEM vs Aftermarket
The Tecumseh 33268 has a specific frame and gasket shape that needs to seat tightly in the filter rack. In our QC room, we check frame width, depth, and gasket adhesion on every sample. OEM filters are consistent. We've opened dozens of cartons and every frame was square within our tolerance of 1/16 inch.
Aftermarket filters are a mixed story. Some are built fine. Others are a few millimeters narrower, which means the filter racks don't grip them tightly. Air will always take the path of least resistance. If there's a gap, unfiltered air gets into the housing. Put another way: the frame is the unsung hero. A perfect filter media with a bad frame isn't a perfect filter at all.
This is even more important when you're running temporary equipment around the unit. On a cold roof, a Lasko heater is a common way to keep workers going through the winter. It pulls dust and debris into the air. An oscillating fan does the same thing if you're using one inside a building during renovations. I've seen a small space heater load a filter in a week. You don't want gaps to make that problem worse.
In Q1 2024, we received a batch of 2,000 aftermarket filters where the gasket was visibly off by roughly 1/8 inch against our standard spec. The vendor claimed it was within industry standard. We rejected the batch, and they redid it at their cost. Now every contract we sign includes a gasket adhesion clause. That's why I always measure before I judge.
Filtration Media: Pleat Count Isn't Everything
The 33268's primary job is to keep compressor internals clean. That means media area matters. More pleats means more surface area and usually lower pressure drop for the same airflow. OEM filters have a consistent pleat count. Aftermarket filters can have fewer pleats to save money.
But here's the part that surprises people: aftermarket filters aren't automatically worse. If the media is the same class and the pleat count matches, they can perform nearly as well. The problem is inconsistency between batches. We've tested maybe 60 aftermarket filters. Maybe 50, I'd have to check. The first batch looked great. The next batch from the same supplier had a completely different pleat spacing and thinner media. That kind of inconsistency is hard to catch unless you cut one open.
I do wish I had tracked pressure drop readings more carefully in those tests. What I can say anecdotally is that OEM Tecumseh filters performed more consistently in the same airflow rig. The aftermarket one that matched the spec also performed well. The one that didn't match increased static pressure by about 18%—enough to affect airflow in a marginal duct system.
Total Cost: A $15 Filter vs an $800 Compressor
I'm not going to tell you that OEM is always the cheapest. It's not. Based on distributor quotes we've collected in March 2025, a genuine Tecumseh 33268 filter runs roughly $18 to $32 each. An aftermarket 33268 can be $8 to $18. Prices vary by volume and vendor, so verify current pricing before you order. But here's where the total-cost thinking comes in.
A filter replacement is a 10-minute job for a service tech. At a $100 to $150 per hour shop rate, the labor cost is already more than the filter. If an aftermarket filter needs to be re-seated or replaced on a second visit, you've erased any savings. If it lets a little dirt through and the compressor fails a year later, you're looking at a $1,500 to $2,500 repair plus downtime. That $7 saving on the filter starts to look silly.
I've had this exact hesitation. The upside of a cheap filter was about $1.80 per unit on a 500-unit order. The risk was premature compressor wear on equipment we weren't there to protect. I kept asking myself: is $1.80 per filter worth potentially calling a customer back in July to explain why their compressors are failing? It wasn't.
Filter Replacement vs Radiator Bleeding: Which First Move Helps More?
Sometimes the filter isn't the real problem. On a cold call, it's easy to assume the 33268 is dirty and just replace it. But if the building has a hot water heating system, you might be missing an air-bound radiator. I've compared these two moves in terms of cost-per-information, and the answer changes depending on the system.
If you can see a dirty filter, replace it. That gives you a clean baseline and costs less than a diagnostic visit. But if the filter isn't dirty, and the complaint is uneven heat, bleeding radiators is the higher-impact move. Air in a radiator keeps hot water from circulating. It's free to fix, but it takes a little skill.
How to bleed a radiator quickly:
- Turn off the heat pump or boiler and let the system cool.
- Find the bleed valve at the top of the radiator. It's usually a small square or hexagonal valve.
- Use a radiator key or a flat screwdriver, depending on valve type. Put a rag underneath to catch water.
- Open the valve slowly. You'll hear a hiss as air escapes.
- Close it as soon as a steady stream of water comes out. Don't overtighten.
- Check the system pressure afterward and refill if needed.
If a room is still cold while you're waiting for heat, a Lasko heater is a practical temporary fix. An oscillating fan helps distribute that heat around a small space. Just remember that both of those are working around the problem, not fixing it. The radiator bleed and filter replacement are the actual maintenance steps.
What I'd Do: Scenario-Based Selection
If you're putting a 33268 on a rooftop unit that serves a critical process, a conditioned warehouse, or a food storage area, I'd choose OEM. The consistency is worth the extra money. The compressor is too expensive to gamble on a 15% defect rate for the cheapest aftermarket option.
If you have a non-critical unit that runs a few months a year, or you need a temporary filter to finish a project, an aftermarket filter can be acceptable—but only if you measure it first. Check the pleat count, frame dimensions, and gasket adhesion before you install it. If it doesn't measure up, don't install it.
In the middle, look at the application. You know the environment better than any filter manufacturer. If the unit sits next to a metal fabrication area or a parking lot, filter load is high. Protect the equipment. If it's a clean office environment with low run hours, the aftermarket risk is more manageable.
At least, that's been my experience with Tecumseh units. We've only tested aftermarket filters on smaller orders so far, so I can't speak for a full season of heavy use. But the ones that matched the spec ran without issues.
Bottom Line
Don't let a $15 air filter become the most expensive part of your HVAC system. Compare the OEM and aftermarket filters on fit, media, and total cost. Use the OEM when you're protecting expensive compressors. Use an aftermarket filter only when you've checked it against the spec. And don't forget the basics: bleed the radiators if you have uneven heat, watch out for temporary heaters or fans that load filters faster, and verify current pricing before you buy.
The Tecumseh 33268 is a simple part. The decision around it isn't.
