If it's REALLY a year old, it would be under warranty.
Why void that warranty by replacing the fan when you can get a new PSU?
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Did you even read what I wrote? I completely informed him to remember his warranty.
Are you aware of the bathtub curve? After a year of use the ELECTRONICS portion of the PSU is proven, into the bottom of the curve and highly likely to be looking at a long life of reliable operation ahead of it, barring external problems like power surges. It's well worth saving if possible especially if you're the only owner and know how it's been used to that point. The fan, however, is trash and always was trash if a sleeve bearing unit; send this thing back on an RMA and all they do is put another garbage fan inside, unlike the quality ball bearing fan I'd pick but also quite possibly with shoddy workmanship. Or send back another PSU with the same garbage fan, but now has to prove it's reliability (burn-in to the bottom of the curve) under the original warranty period that's now shorter.
No, I'd totally choose to replace the fan, but I'm techie enough to open up a PSU and do that work. I'd only return it under warranty for more serious failure, or if still in the exchange period at the retailer.
And I think you give them way too much credit for 'designing' the PSU to operate with a fan of 'specific static pressure'. No, they just use what's cheap and moves enough air to 'do the job' even if barely enough. And they fully expect it to operate at a fraction of the original airflow after a short while as...yep, it's cheap and won't stay spinning for the life of the rest of the PSU it was put into. The range for success (if you can call it that) is immensely wide. It's fairly easy to pick out a static pressure fan that will work and is more likely to move even more air. And being a high(er) quality ball bearing or hydro bearing unit it's going to be the last fan I put in it all the while moving even more air than the original most likely would have.
I do get miffed at the elitist attitude that all readers of these forums are incapable of getting into the guts of doing work like changing the fan in a PSU. It's a little more involved than changing a case fan, and has some safety issues to consider, but not at all impossible. If offering it as an option upsets you, just look away. But the better thing is to offer your ADVICE on doing that job SUCCESSFULLY so that all would benefit and at the same time raising the level of discussion.