During the years of war, before heaters and air conditioners were invented, people used to heat their homes with ovens. This held a certain risk, but they were used to it and so it was ok. Nowadays some people do this as well, but this is not a great idea at all. I hope I can give you enough proof bellow to forget this idea once and for all.
Unlike heaters, ovens don’t have a temperature meter, which prevents them from overheating. As the oven burns oxygen in the room depletes. If it reaches critical level, carbon monoxide will begin to take over the space. Sooner or later the flame in the oven will be extinguished. When that happens gas will begin to leak into the house, filling it up. You can see where this is going, right ?
Many people have died from gas poisoning and suffocation years ago, because they fell asleep while leaving the oven open and on during the night. Nowadays, with all the heaters available on the market, relatively cheap, and air conditioner, almost nobody will lean on this heating method. However, in certain situations, people may do it, out of pure ignorance. I strongly wish that you’d be careful and restrain yourself from any such acts and encourage your friends to do the same.
Also ovens may overheat and malfunction while you do this. Professional oven cleaners in Northamptom say that they have seen the damage that is caused from mistreatment and this is on of the more severe cases. Many fire teams have faced burning infernos, caused by an ignited oven, or gas, leaked by one.
This is no joke because in the US this is considered one of the main causes for combustion. In the UK people are smarter than that, and rarely rely on such heating measures. However, occasionally, an old household may do something like this. It happens far to often to be neglected and so, again, I imply that you must be cautious with your oven use. Constant maintenance and oven cleaning are the means you have to do in order to ensure your safety.