I have a really old oven that that has a pilot light flame rather than an electric ignition. I wanted to see if the oven was hot enough to dehydrate food with just the heat from the pilot light. Since the pilot light is lit and burning all the time, if this works I will be able to dehydrate food for free and also not have the expense of buying a dehydrator.
I discovered after my initial testing that cutting the fruits and vegetables thin works best. I tried dehydrating what I had available. As shown I cut up an apple, baby carrots, a banana, and a pepper.
According to my infrared non contact thermometer, the oven temperature was 109 degrees F. Everything looked "done" after 12 hours except for the apples. I dehydrated everything for 36 hours. I was very impressed with the baby carrot slices. They are tiny. Everything tastes delicious. Your results may vary.
I seem to recall that the local feed store has giant bags of carrots from time to time. Hmmmm.
The carrots reconstituted nicely in hot water. I showed the plastic bag of dehydrated food to someone at work. He said "Potpourri?". I suppose you could dry flowers this way.
I have been using the heat from the pilot light to get every last little bit of coconut oil out of the jar for years. This also works to soften up or melt butter but it takes some time.