That depends on the size of the room, the ventilation, the ability of the room to get rid of heat by other means, etc. People generate energy through chemical reactions in the form of heat, and that heat has to go somewhere, so it gets conducted, convected, and radiated into the surrounding room. Once in the air, however, it's just heat.

You can calculate how much heat it is, by the way: a Calorie (or kilocalorie) is about 4,200 Joules of energy. An average human burns about 2000 Calories per day, and a day has 86,400 seconds. Divide the energy by time, and a human outputs about 100 Watts of power. Thus, a person heats up a room at about the same rate as does a 100 Watt lightbulb.

That would depend on the size of the room. Humans produce about 100 watts of heat, like old-fashioned 'Edison' light bulbs that feel hot when you touch them.

There's a rechargeable handwarmer that gives 12.6 watts of heat. My little electric heater on its low setting gives about 500 watts of hear.

There are houses that have no heating - they are carefully built to keep cold air from getting in. They're called 'passive houses.' They get moldy and smelly unless there's a ventilation system that brings outdoor in and heats it with heat from the smelly air going out.

Here's an article about a train station that uses the body heat of the 250,000 people who go through it each day:

I was talking about your question with my family last night, and my son-in-law told me about those houses.

How much the temperature in the room rises will depend on how much heat each person emits, and how much heat each person emits depends on many factors, including how much physical activity each person does or has done recently, whether he/she has eaten recently, and so on. Furthermore, the temperature increase will also depends on the size of the room, the degree of insulation of the room (some wall materials trap heat better than others), among other factors.