Boost towers help increase the damage of nearby towers and also assist in cooling them down in hot climates. Best part of all, their effects stack! For example, a damage delivering tower completely surrounded by eight level one Boost towers would receive an 80% (8 x 10%) damage boost.
Pro tip: Boost towers are especially helpful in the desert. They cool down other towers faster, so the more boost towers, the merrier.
See them in action ->http://www.kamcord.com/v/2WD7WlVVuXi/