Low temperature PC build?

I haven't found much info on this, perhaps because it's not that complicated. Is it as simple as selecting low wattage components in a decently ventilated case and calling it a day? Maybe an APU instead of a CPU + basic GPU? My parents could use a new machine soon and I volunteered to put build one for them. It's "just" a general use desktop machine, the fanciest thing it'll have to do is play HD video in like the 10th tab open in Chrome. Their old computer is pretty old and struggles with the basics these days.

It'll be in a semi-enclosed area so I'm thinking a smaller form factor might be good as well to give it a little extra breathing space. But the primary goal will be to generate less heat, rather than just manage heat better. mITX might be cool, but I'll have to check if they currently or may have use for more than one PCIE slot.

Why stress yourself with building one if one of those pre-made office PCs could do the trick?

Here's an example of the cheapest thing I'm thinking of that we sell at work: https://www.harveynorman.com.au/acer...b-desktop.html

Dual core AMD A6, 2TB HDD, massive 8 gigs of RAM, comes with KB and mouse.

You can buy it, 'set it up for them' and maybe slap in a bit more RAM to account for boomer browsing habits and they'll be good to go. Perhaps do a clean install of Windows to eliminate the bloatware. Warranty support too!

I would find something in the $500 price range with newer components for more longevity. If they're just browsing the Googles and watching the YouTubes then they won't need much.

Mini PCs (think those attached to the back of a monitor at a point-of-sale terminal) come with no bloatware and I've seen them with coffee lake processors and 8 gigs of ram, so perhaps more ram can be added.

Have you thought about a Chromebook? We've got a couple of them that were like $350 a pop and can pretty easily handle tasks like that.

Some interesting ideas. Chromebook is probably a no go unless it's permanently in a docking station that has easy access front I/O. Primarily my parents have a hard time with change (they're far beyond boomer age!) so my thinking was to get them something that will still be good in 10+ years, meaning a little extra performance built in for a while (and an SSD for sure). Imagine my disappointment to see that the new Ryzen 4000 APUs are OEM only. They have a couple 35W TDP processors that look pretty great. I'll have a look-see for prebuilt PCs that are close to what I'm thinking.