I think my cats like the purr of my air purifying system as they often sleep on top of the unit. I guess it relaxes them and reminds them of sleeping by their purring mom. Sometimes my female cat bites and kneads the comforter which they arrived on when I got them as it still has the scent of their momma on it. I have the comforter on my small space heater which she likes to sit on in the corner of the living room. It is so cute to see her sniff the comforter and then start biting it and purring because she smells her mom. I wish I could reunite them with their mom one more time to see how they react seeing her, I’m sure it would be a bittersweet moment. My HVAC rep is the one who gave me the kittens a few months ago and he is going to set me up an appointment with the local business to get them checked out to make sure everything is okay with them. I think they are fine and I see no fleas on them at all. I want to ask the people at the local business if I should give them a bath once in a while or if they are fine the way they are. I could also go to the HVAC company later today and ask the HVAC tech if they need a bath as she has four cats herself. I think the way they are cleaning themselves all the time is enough to keep them clean.