The fan noise really isn't an issue. It kind of depends on what you are doing. Just surfing the web? The fans shouldn't even turn on. When you start adding more tasks they might turn on. Again it depends on how much of a load they are on the system. If you are web surfing, working in Word and/or Excel, transferring files, etc. all at the same time, and even doing so on multiple virtual desktops, the fans will kick on, usually at full blast. This is also the case when you start transferring large amounts of data around the computer, or to an external drive, or performing backups. Often, this is actually to keep the hard drive cool, not necessarily the CPU.
However, even when the fan kicks on full blast, this is not necessarily an issue either. This is mostly a personal issue, and often comes down to where you are using the Spectre. For example, I actually though the fans were a bit loud myself, and noticed them kicking on often, as I would multi-task quite a bit and use many virtual desktops, and run multiple virtual machines. After a while I realized this was mostly because of where I was working. I would only really notice this in my home "office", which is really just a large walk-in closet we weren't really using, and in there you could pretty much hear a pin drop. Outside of that, I would notice them but they wouldn't bother me.
So yes, the fans can be a bit loud and annoying, but only really in VERY quiet environments, and actually, compared to laptops like the Lenovo Yoga 910 they are relatively quiet even on full blast. Only the Macbook pro beats out the fan noise on the Spectre, and thats only because Apple's software will only switch their fans on at the last possible second, and then they pretty much match the Spectre as far as noise.
All this really depends on your personal preference though and your tolerance for fan noise. Aside from the Macbook Pro, you really can't find a laptop that will do much better with fan noise, unless you go for a laptop with a Y-Series processor (like the Dell XPS 13 2-in-1). But if you are only using a 4.5 Watt processor, and if fan noise bugs you that much, depending on what you are doing (ex: just web-browsing, using Word, etc) you might just be better off getting a tablet with a keyboard (ex: the Samsung Galaxy Tab S3).
HP - Spectre x360 2-in-1 13.3" Touch-Screen Laptop - Intel Core i7 - 16GB Memory - 512GB Solid State Drive
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Dell - XPS 2-in-1 13.3" QHD+ Touch-Screen Laptop - Intel Core i7 - 16GB Memory - 512GB Solid State Drive
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Samsung - Galaxy Tab S3 - 9.7" - 32GB - Black
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