Disclaimer: I am not advocating the use of electric blankets/human heating pads for every day use but...

The blanket was INSIDE the cage. What kind of idiot does that!? Human heating pads (if they are the old style w/o the auto shutoff) in conjunction with a good thermostat can be used in a pinch to keep temps optimal if your UTH stops working. I have at times used them full time but the risk outweighs the reward. They are most definitely a fire hazard when compressed by a tub or cage.