Despite the name, a desktop PC does not have to be on a desk. Of course, the huge tower PC would fit well on the floor. However, you should think about ventilation and dust so your gaming PC does not overheat.
Blocking Carpet Can Airflow
Modern PC cases are usually not quite flat. They have feet so their base lifts off the ground a bit. Under the housing there is an air flow. All PC cases have fans that emit hot air and vents that allow cool air to enter. In some cases, there are even additional inlet fans that further facilitate the intake of cool air.
That's the way it should work anyway. If you place your suitcase on a thick plush rug, the rug may block this airflow. This is very bad if the air is to flow through the bottom of the housing into the computer or exit from it. It is bad even if there is no air in or out of the case ̵
Of course, if you have a short carpet on your floor, the PC may be able to sit under it with enough airflow. And if you have no carpet at all, this is not a problem. Your PC will sit on a flat floor at home, just like on a flat desk.
Before putting your PC on the ground, you should think about the airflow. Do not place your tower PC on thick carpets. If the carpet is a problem, place it on a platform or place it on the carpet. For just this purpose, you can buy roll stands that also make it easier to move your desktop. Even if you put a piece of wood on the floor and put the PC on the wooden platform, this problem is solved, even if it is not nice.
Your PC sucks more dust on the floor
Your floor is likely to contain more dust, hair and other debris than a desk or table. This is important: The fans of your PC draw in air and blow out air. These fans can suck dust, dirt and other waste into the PC.
This happens regardless of where you set up your PC. Even if you have your PC on a desktop, you may occasionally want to clean it with some compressed air. Your PC will probably be soaking up more dust and dirt on the floor. Dust obstructs the cooling of your PC and gets hotter when it has to be cleaned.
Dusting and cleaning around a PC that is also on a desk is easier. If it is in a corner, how often will you move the case of the PC, vacuum it and dust the cables there? It is easy to get rid of the cleaning and build dust on your PC.
If you leave your tower PC on the ground, you should wipe it off regularly – probably more often than you need, if you keep it on a desk. That depends on how dusty your floor is, but you might want to check every few months. You should also remember to clean around and behind the case to avoid accumulation of dust.
Apart from that, the floor is fine
Problems with ventilation and dust, both of which lead to overheating, are the main reasons that geeks usually recommend against placing a desktop PC on the floor. But if you have both things under control and thought through, is there really a problem when you leave your PC on the ground? No not at all. It's okay.
In some situations, the ground may even be preferable. There's a good chance you'll have more room on your floor than your desk, and putting your tower on the floor will free up some space. Some people with heavy PC towers may be worried that they will fall off a desk and fall on children or pets.
Of course, your circumstances may be different. For example, if there is a risk of flooding, your PC will be more secure when it is not in use.
All these considerations are particularly important for gaming PCs or workstations that generate a lot of heat. If you have a low-power desktop that does not generate much heat, ventilation is not such a big issue. Modern, lightweight desktop PCs are often small boxes that would easily fit in the corner of your desk anyway.