Walrus...I installed a massive such system for an indoor pool; as you might guess, there is a real challenge keeping the humidity down!
In that system, it was not possible to operate economically until we installed speed controls on the blowers. With them in place, we were able to reduce current draw from almost 30 amps, to less than 8 (on each of two fans).
There are perhaps other solutions ... dampers and such ... but (energy considerations aside) you are still left with the need to sort out your control wiring. We've gone beyond the sparky just running the power, and everything being self-contained in the unit.
