The general consensus is that you should not get a covered litter box. Although I can’t say that the answer is clear cut and one hundred percent definite. It depends on the circumstances, and the personal preferences of the cat’s owner must play a part in the decision although they are secondary to those of the cat.
Covered for human’s benefit
Perhaps the most important aspect of the question is the reason for buying a covered litter box. It is covered in order to keep inside the box the dust and substrate that might be carried out by the cat. The cover also stops some of the odours coming from the litter tray to the outside and permeating the room in which the litter box is situated. In all cases the cat’s owner benefits and not the cat. Therefore, I have to deduce that the cover is for the benefit of humans and not felines. It follows that a covered litterbox is less suitable than one which is uncovered from the cat’s perspective. It could be argued that the concentration of dust trapped inside the cover may make the air harmful for a cat to breathe. Some litters are very dusty.
Other arguments against a covered litter box are that they are dead ends. This means that a cat may feel trapped inside it, which may be uncomfortable if they live in a home where there are dogs, kids and other cats. Perhaps the cat is a little timid and being bullied or intimidated by another cat or cats. If they have to go into a dead end to go to the toilet it may put them off.
On a practical level, the cover itself might be hard to wash and it needs washing as it can become a little bit manky over time and perhaps neglected. This may create a hygiene problem.
A further issue is that a large, long-haired cat may well brush against the sides of the door (cat flap) of the litter box cover and in doing so create a static electricity charge. The cat may discharge the electricity generated causing a mild shock. If this happened once it might put them off using the litter box.
Too smelly for cat?
One expert says that the cover retains the odours inside to the point where the smells are too strong for the cat. I’m not sure that this is correct because litter boxes should smell to a certain extent of a cat’s pee and poop because the smell draws cats to the litter box. It is a cat toilet and it should smell like it as it encourages a cat to use it and not go to the toilet inappropriately but it should not be an overbearing smell which upsets the owner.
Personal experience – counter arguments
For many years, I used a covered litter box without any problems whatsoever. At the time I had a female cat. I used a wood-based litter and the litter box was in the living room because I lived in quite a small flat. As I said, there were no problems whatsoever. My cat used it perfectly and it did keep in some of the smells and the litter substrate. Therefore I cannot argue too strongly against them. As I said at the beginning, this is not a black and white situation. I believe that there are advantages to covered litter boxes. Perhaps they are particularly useful under the circumstancs in which I found myself i.e. living in a small flat with one cat. Under these circumstances there is no chance of a cat feeling unnerved by going into a confined space and the other potential issues were irrelevant.
As a postscript, it is advisable to bear in mind the following (1) don’t use a liner for your cat litter tray as some cats don’t like the texture of a liner and their claws can get stuck in it (2) keep the litter box clean by raking through the litter at least once daily (3) use unscented litter and don’t use deodorisers to camouflage the smell (4) locate the litter box for your cat’s convenience not your convenience (5) make sure that there is one litterbox per cat plus one extra (6) don’t overfill the litter box or underfill it (2 inches is about right) (7) use your cat’s poop to help assess her state of health. Poop should be quite firm and the colour of milk chocolate and deposited once or twice daily (8) get the right size litter tray (1.5 times cat’s size).