I have to say, I was worried about three things when I bought this heated cat bed. 1) Would it be too hot? 2) Would my cat like it? 3) Did I get the wrong size? (20") 1) The bed does NOT get too hot. It heats to the normal body temperature of a cat. So when you plug it in and give it 20 minutes, place your hand on the pillow FIRMLY and let it set there a minute, you will feel the warmth. In other words, with your cat's body weight being on it, the heat will be apparent. You just won't feel it if you place your hand on the pillow for a second, like you would a regular heating pad. Remember too, that the heating pad element is under the pillow in the bed. 2. The day the bed arrived, my cat stepped in it, and immediately hopped out. I was thinking, "Oh no! Another dud. Maybe it's not warm enough to attract her to it." My cat normally lives ON me... like if I'm sitting down, and I almost always am, she's on me. I purchased the bed because I feel badly for her when I'm out, and doesn't have the comfort of at least my body heat. I had to do a lot of cleaning. Gertie (my cat) kept coming over trying to get me to sit. I could see she was pretty peeved after a couple of hours of this, and it was past her bedtime. With that, all of a sudden, she climbed into the bed and went to sleep! I was thrilled! Then I wondered if it was just a fluke, never to happen again.. but nope, no fluke. After that, she has chosen to sleep in it many times, when she could've just climbed on my lap like usual. This is not to say, btw, that I have been entirely replaced, lol. Just partially...and it's actually a good thing. It frees me up to get up to do something without guilt for having making her get off of me. I know now she's still happy and warm when I get up. 3) Gertie, for the most part, sleeps in a ball, but does occasionally also sleep stretched out. I probably should have measured her length, but figured I'd just guess and need the 20" for those stretched out times. Since she usually sleeps in a ball though, I was a little worried that the smaller size could be better though.. more cozy, ya know? I got the 20", and it's definitely the size I would get if your kitteh ever loves to stretch out. It's not confing in the least. When curled up, she is several inches away from the sides (unless she's off-center and laying against the side), but it doesn't seem to bother her. A few more thoughts... Safety. I was also concerned that when it's plugged in, it's always on. After seeing it in use however, I'm not so concerned. It just doesn't get warm enough to cause an issue, I think. I'm no fire marshal, so it's just my gut saying that. I had just purchased a Ring indoor camera, so I thought that would give me extra peace of mind for when I wasn't home. Also, I am thinking that if I plug this into a smart plug, I will have the ability to turn it on and off. The hood. I wasn't sure whether she'd like it or hate it. Luckily, it zips on or off easily. Gertie likes to climb in and umder things, so I tried it first with the hood, and later without. She seems to like the hood ON better. Don't worry that it could be too confining or claustrophobic. It's not like that at all. It's just enough that probably makes it feel a little more of a safe place for her to sleep than anything else. So if you're trying to find the right heated cat bed for your kitteh, I would recommend giving this one a go. I'm so glad I did. If Gertie spoke English, I'd imagine she would say, "Momma ae lubs dis ting! Fank yew sew much!"