Thermo perch or heated pad - dangers?

I have one of the extra small avitec heat panels for Figgy and one for my crimson bellied conure. I love them, and so do they. In the winter I leave my on 24/7 and have had no issues. I checked with the company on how long they could be left on and they stated they leave theirs on from October through May without turning them off. I use the cage mount instead of wall mount, it hangs on outside of cage. My birds just love them !! When they get chilled they will sit in front of them. At night I still cover their cages on three sides with fleece blanket but heat panel can't be covered so I keep that side open; which helps hold in heat at night from panel. During day I put small towel over top of cage just above panel on that side so that also helps hold in warmth during the day. After their baths they both run right over to preen in front of their heaters. Just have to make sure cord is positioned so that can't reach it but where cord is located and the cage mount really helps so they can't reach anyway. Good testimonials also about them on their web site. At night they both still prefer to sleep in their tents on other side of cages but the heater helps keep the temperature constant and warm. I have been considering getting a couple for spares Incase these quit working- I don't think Figgy or Ollie would be happy without them. I have been using one for my parrotlet now for almost 2 years and my conure is a baby but I made sure his cage had one from the first day I brought him home. In summer I don't use them during day unless they had a bath, but I do use them at night during Sumer because we have air conditioning and my husband prefers it cooler. I think they are well worth the investment.