The chimney is smoking

This is a gas water heater. Warm water for the bathroom and kitchen. It's frosty outside. Therefore, warm air turns into steam. Very often such steam looks like smoke. Therefore, there are times when neighbors think that someone’s house has caught fire. One day one of our neighbors saw this smoke from a distance. And she called us. She said: “I see smoke coming from your house. Your house is on fire.” We were at home. And they were very surprised. And then we laughed. But vigilant neighbors are good. In summer there is no such effect. In warm weather, when the gas water heater is turned on, no smoke comes out.

This is how a gas convector works. This equipment heats the house.
Video: "Started heating the house for Dora and the kittens"
https://rumble.com/v3wwhmy-started-heating-the-house-for-dora-and-the-kittens.html?mref=1udk2y&mrefc=3