Is fan noise a valid complaint from a customer?

VALID.

The fans should NOT be at full speed all the time. I would complain as well.

Change the settings to be temperature sensitive.

Yes, it is a valid complaint.
A well built machine should be running smooth and quiet.
The fan should ONLY be running to deal with ehat, and should only ever be making noise when it is running at max power to deal with a LOT of heat. TOO MUCH heat.

How do you build computers and not worry about fan noise?
Fan noise is awful!!

If the fan is running all the time, you did not build him a good computer.
You built him a computer that the fan is going to overheat or wear out quickly.

actually yes it is and if you want them too stop calling fix it properly

Some people want them quiet so it's a valid complaint. There are settings to make the fans run quiet when the PC isn't that busy. You'll have to explain to the customer that when the fans run at full speed, it's his fault for running too many intense programs.

Valid complaint. If the fans on the CPU cooler are too loud under load, you should select a fan with better static pressure and/or change the fan profile in UEFI/BIOS. If the CPU cooler is an AIO, then you need to set the CPU_FAN header in the BIOS to run at full speed by default, and set the rest of the case fans on a mild fan curve, as they aren't going to be cooling the CPU, and just really have to move air in and out of the case.

I am the Statesboro PC Doctor yes certainly fan noise is a valid complaint the PC should not have to have the fans running full blast at all times to keep the system cool if those fans are having to run all the time something is wrong and if you're the Builder you should take a look and see what's wrong is it really worth your reputation? Word will get out all over the place that you build computers that are noisy with the fan running all the time and nobody will buy your computer anymore mine don't have the fans running all night and all day I have no problem at all with my customers and if I have a problem with my customers I offer them a refund and get rid of them once I give you a refund you don't have a valid complaint anymore and I can always take the computer back refurbished and resell it and at least break even. Why lose business over one dissatisfied customer give the man his money back and get rid of him and tell him I'm sorry I can't help you here's your money back

it could be valid or unvalid, depending on what he was doing
if he was setting the fan speeds all the way up, that would obviously make noise
if hes just running too many heavy programs at once, then the fans will obviously be at full load, and the guy just doesn't understand computers

if it's doing it by itself you probably did something wrong
maybe it doesn't have enough airflow, or you're using a weak cooler with a warmer processor
the fans might not be installed properly, or they are just bad fans overall

so couple things to ask him:
did he change the fan settings?
how many programs is he running at once?
did he tamper with the computer at all?

either way, if you're making money from him, then you could just take it in and easily fix it

You are in business to keep customers not send them to another vendor because your people skills are lacking. If they have a problem with a fan and it's within a reasonable warranty time period then replace it. Otherwise you may lose a customer to your stupidity.. I build my own PCs and that includes designing and etching my own motherboards.. I simply dont have time for people like you whose only care is throwing a few components together and calling it a PC and selling them to people who expect to get what they pay for and get only crap service in return

I’m almost totally with you on not caring about having a noisy PC. It’s nice to hear the gentle white noise but I have bought a few high performance fans that are too loud. These fans are industrial fans made by Servo.

However things have changed and now a Quiet PC with RGB lights is in style. Many of these aftermarket CPU coolers and AIO coolers come with fans that won't go beyond 1500rpm because people don't like noise. The companies that make computer cases cater to these people by putting 1000rpm-1500rpm fans in the case and using a Plexi-Glass side door so the user can see their motherboard light up. AIO coolers now come with a software program that allows the user to adjust the fan speeds. If you don't download the software then the fans and pump will run at around 50%, while being called "Balanced Mode"

It's kinda like ceramic brakes. They don't work worth a sh1t but manufacturers put ceramic brakes on automobiles because people want quiet brakes.

Sometimes I rebuild computers then sell them on Craigslist. I can say that a loud PC is too much for some people. What I’ve noticed is my definition of quiet is different than what someone else’s definition is. There are people out there that think a PC should be dead silent and somehow People have become weird like that over the last 5 years.

The customer may not have a leg to stand on if you sold him the system as is. However people can be vengeful and he could possibly write a nasty Craigslist ad about your service. This happens in my area occasionally. If you used a stock cooler then something could be wrong with it or possibly the fan speeds in the BIOS got cranked up to the maximum. it’s worth checking out.