Line the walls' interiors with insulation. Using insulation will decrease the amount of air that escapes through the walls.
Avoid building a window. Windows let air seep out of a room.
Ventilate the room. If you are conducting experiments, you will need a well-ventilated room so that the chemicals do not harm you. Also, ventilation will prevent mold growth.
Tile the floor of the room. Unlike wood, tiles do not expand and contract with excessive heat exposure.
Invest in a heavy-set door that will keep the air inside the room. Just like windows, some doors will let air escape.
Install a climate-controlling system such as central air and heating. Read carefully what each system requires because some systems need access to a computer.
Arrange the room to your convenience. For example, if you are testing bacteria in exotic plants, line microscopes along the wall on a table. If you are monitoring the growth of trees, line the plants in rows throughout the entire room.