If possible try to completely enclose the area around the plants. About 2ft wide and 4-5 ft tall should be enough although 6ft tall would be ideal.

Then put a high flow fan at the top of the enclosed area/cabinet and have it exhaust air out of your grow area.

This should be good for about a 5 - 10 degree drop. I'm going to go with 5 degree.

You want the temperatures to stay below 85 degrees. Ideally you want them between 70-78 degrees.