I am sorry, the whole thought of this cracks me up since the rules guiding the Amish states that they cannot use power line electricity. That right there tells me this is a con job of one degree or another.
The mantles are the Amish component, I believe. The inclusion is to mislead the common buyer the rest of the unit is made to that assumed level of quality.
Unless I read it wrong, the thing is MADE by the Amish, not USED by them. They made all the cabinets in my travel trailer too, but they don't use them to my knowledge. Lots of products are produced by the Amish, they are usually of exceptional quality.
One of my former bosses had his home built by them. Hand saws and hammers, they did a great job. He showed up one day unannounced and heard them listening to the radio, he told them if they did not have the place done on time he was going to notify the elders. Had another Amish gentleman that owned the business that refurbished our Injection Presses. Had employees fire them up and drive him everywhere. I realize it and still stand by this heater cracking me up and as I said at some level it is a con job. Probably very good heaters.