This may be good advice, particularly if you live somewhere much hotter than the UK. However, you needn't assume the cooling efficiency is inadequate. Just crank the central heating up to something a little higher than the hottest temperatures you experience locally then run it under as heavy a load as you can for as long as you need to in order to satisfy yourself that it's safe to use sans fan. Regularly cleaning the unit should help too. The Silverstone PSUs all seem to have a single temp status LED and I'd imagine you'd see quite quickly if it couldn't cope with the conditions. You could abort as soon as the warning LED lit. I recognise that a device need not be truly silent in order to be effectively so, and perhaps taking such a risk is unnecessary, but I've bought a fair few "silent" or "quiet" fans in my time that were nothing of the sort. I've also had lots of problems with fans that seem to have (or develop) defects that cause noise so I'd rather just be shot of the whole spinny roundy horror show.