Look, I'll just say it: I think the whole “universal” trend in HVAC parts is overrated. Not useless, but definitely overrated. When I took over purchasing for our 400-person facility back in 2020, I figured “universal” meant “just as good, easier to stock.” Three years and one costly condenser coil cleaning disaster later, I've changed my mind.
Here's the thing: a specialist who knows their limits beats a generalist who promises everything. And when it comes to something like a Tecumseh air filter—specifically the 36356 model we use across three locations—I'd rather buy the exact OEM part than gamble on a universal fit that might sort of work.
My argument: “Universal” often means “good at nothing”
I manage about $180K annually across eight vendors for HVAC, plumbing, and electrical. When I consolidated orders in 2022 to save time (our ordering process was eating 6 hours a month), I switched to a “one-stop shop” supplier that claimed to cover everything. On paper, it was great. Same vendor for compressors, air filters, even cleaning supplies for condenser coils.
In practice? The Tecumseh air filters they shipped were not Tecumseh. They were generics with a sticker. The condenser coil cleaner they recommended left a residue that actually reduced airflow (which, honestly, I didn’t even know was possible). And when I tried to clean our unit with their “all-purpose” solution, I ended up paying $400 for a service call to fix a sensor that got gummed up.
Why specialized parts matter more than you think
Three things convinced me:
- First, fit is not negotiable. A generic air filter might fit 80% of the way, but that 20% gap lets dust through. For a Tecumseh 36356, the OEM seal is precise. (I learned this after we had to replace the blower motor on unit #3—cost us $1,200 because the universal filter let debris through.)
- Second, cleaning condenser coils the wrong way can ruin them. People think all cleaners are basically soap. Actually, some are acidic, some are alkaline, and using the wrong one can corrode fins. I’ve never fully understood the chemistry (if someone has insight, I’d love to hear it), but I now ask vendors: “What cleaner does Tecumseh recommend?”
- Third, warranty compliance. I know it sounds boring, but if your unit fails and you used a non-OEM air filter, the manufacturer can void your warranty. That’s not a theory—it happened to a colleague who installed a “universal” filter on a condensing unit and had the compressor fail.
The counterargument: “But universals are cheaper and easier”
I hear this all the time. And sure, if I were managing a warehouse with 50 identical units, maybe I’d stock one universal filter for everything. But for our 3 locations with mixed equipment (some Tecumseh, some Copeland, some older models), the “universal” solution meant carrying three sizes anyway. And the price difference? About $2 per filter. Versus $1,200 in damage when one failed.
The assumption is that universal parts cost less. The reality is they often cost more in total (Source: my own purchasing data from 2022-2024; your mileage may vary). I’d rather pay $18 for a real Tecumseh air filter than $12 for something that might work, might not.
What I actually do now
I buy Tecumseh 36356 filters from our authorized distributor (pricing as of February 2025: ~$16-22 each depending on quantity). For condenser coil cleaning, I use the manufacturer’s recommended cleaner—not a universal degreaser—and I follow the instructions to the letter. (Skipped the final rinse once because I was in a rush. That was the one time it mattered. The residue caused a 15% efficiency drop.)
The vendor who told me “this isn’t our strength—here’s who does it better” earned my trust for everything else. I’d rather work with a specialist who knows their limits than a generalist who overpromises.
