An aroma of freshly cooked ugali greets us when we arrive at Jacob Mwangi's workshop at Gaikanja shopping centre in Nyeri county.
We are informed that the accompaniment, (a mixture of kales and spinach) will be ready in less than 15 minutes.
The lunchtime meal is prepared on a dummy of an oil-burning stove, which has been under fabrication for the past one week.
The stove is made using old steel pipes, but one of its most unique features is that it runs on used engine oil.
At a first glance, the cooker can pass for commercial burners found in appliance shops, but it has a few variations; the entire structure is made of old steel pipes.
There are two mini fans on one end of the frame and the most distinctive difference is that the stove, has a cylinder adjacent to the burners. It is this canister from a used mini-LPG cylinder that stores the oil, which feeds the burner.
There are also two taps at the bottom of the suspended cylinder that when turned on, dispense fuel into two funnels that are connected to two pipes.
The two pipes eventually lead your eyes to two burners from where one cooks from.
“That black liquid is old engine oil, which we have drained from a car engine at the garage. It is the main component in this innovation since it powers the stove,” says Mwangi, who is assisted by four technicians.
Mwangi, a mechanic, adopted the idea after watching a video on You Tube by Creative Inventions LMTN (an American self-made crafts).
The YouTube video, which was posted in 2022 has 1.2 million views and 11,000 likes.
Mwangi says he makes a minimum of Sh25,000 profit for every stove he sells.
He says the innovation has helped him preserve the environment by putting used oil into use.
“I decided to actualise the idea at a time when the cost of fuel was going up and everyone was looking for an alternative," Mwangi says.
"Besides being environmentally friendly, this jiko also provides an easy avenue for mechanics to dispose used oil."
However, the two automatic motors that help to supply oxygen to the burner are operated using electricity.
The used oil is then allowed to flow down to the cylindrical burners and once there is a sufficient amount of oil, the flame is ignited using a normal matchstick.
“In our fabrication, we have installed an internal fan, which upon rotation, supplies oxygen to the burner,” Mwangi says.
In less than one year, the mechanic has sold 10 stoves. On the day of our visit, he was finishing his 11th stove.
The first customer returned the stove due to overheating, forcing Mwangi to make some readjustments on the product.
“I had initially installed one motor, but now I am installing two motors, which have a timer. The motors have sensors, which regulate the heat generated by the motors," he says.
"So when one motor gets hot, the functions are automatically shifted to the alternate motor, to ensure that it does not overheat.”
Once ignited, the stove can run continuously for more than 12 hours. A single stove uses 20 litres of used oil in a month and Sh1,000 electricity bill.
Due to its proven efficiency, Mwangi has urged institutions such as schools and hotels, to buy the stoves, which he says will help cut fuel costs.
“The stove is safe; it doesn't emit smoke. The cost is also pocket-friendly for both domestic and commercial customers. I am currently selling a commercial stove at Sh40,000 but a domestic one costs Sh15,000. An even smaller version of the domestic use will cost you Sh8,000,” he says.
