With winter here and our first snow storm coming up soon, I wanted to finish this project, I went to my local hardware store and bought some Terracotta pots, nuts, bolts, washers, to assemble a terracotta heater. With about 3 tealights, which burn for about 3 hours under the pots, if should increase the ambient temperature of a room by about 10 degrees Fahrenheit. I have been using these for about 3 days before writing this without using any other heat source. Temperature outside has been lingering between 30-35 Fahrenheit at night, 40-50 Fahrenheit depending on cloud coverage during the day, and with 2 terracotta heaters, my home has been sitting at a comfortable 75 Fahrenheit for the past 3 days.
3 plain terracotta clay pots with one drainage hole in the base. Ensure there is no paint or treating done, we don't want that burning off and causing toxic fumes to be released. Each will be able to nest within the other with around an inch or so or air space between them. The bolt will run along the inside through the drainage holes, alternating the washers to spread pressure off the pots, nuts to hold them in place, and nesting the pots alternating in this way. The legs will allow the nested pots to rest on the base allowing for air to flow through the bottom.
These heaters get very hot, and depending on the candles used, like tea-lights, have an oil base. So the risk of a flash fire is possible. The surface temp of my heaters range from a comfortable 90-100 Fahrenheit at the bottom to being able to boil water at the top.
In a particularly small room Carbon Monoxide poisoning is a risk, make sure you have proper air flow and a way to diffuse the hot air to around the house.
https://ikeahackers.net/2016/11/terracotta-heater.html
https://www.bobvila.com/articles/genius-terracotta-pot-heater/
https://www.survivalsullivan.com/make-clay-pot-heater/
