ESL classes are taught in all kinds of classrooms under all kinds of conditions. However, there are some features of a classroom that are desirable and which can contribute to the learning of the students. For example, it is desirable to have a classroom that has movable desks. This is important so that you can use a variety of smaller size groups whenever you desire. Students can simply be told to pull their desks to a particular area of the room and into a particular arrangement. If individual movable desks are out of the question, the next best set-up is tables with movable chairs. If you have to use a room with chairs or desks attached to the floor or each other in long rows, your problems of getting students to interact will be greater.
Other desirable features for an ESL classroom include a large blackboard, a bulletin board at the front where you can tack things for all to see, a large table at the front of the room where you can place real objects to work with, good lighting (particularly if you have any elderly students), and a means for controlling the air and temperature. It is also desirable to have a room that is not penetrated by lots of outside noise. Learning a language under optimal circumstances can be trying; learning a language to the accompaniment of outside motors, traffic, and talking can be almost impossible.