DIY: Rocket Stove Mass Heater - it warms your house for almost nothing! This post has videos & lots of info about these heaters + materials used to build them. You may already have some of the materials.
"The Onil Stove. Better than a 3 stone fire for sure! It seems quick and easy to put together. I think I'm suppose to be amazed, but I don't find it as impressive as, say, the Justa stove. Or the impressive Uganda stove.