What reason does your handyman give for needing a second fan in your attic? What's going to be different for your house? I'm assuming your attic is a typical uninsulated attic in the US. I live in Texas, and as far as the eye can see there are houses with uninsulated, passively-ventilated attics. Almost no one has powered attic ventilation. I have a thick layer of blown-in insulation up there, and with the volume of air your handyman wants to move, I'd be concerned the insulation would move with it.
In an ideal world, all our attics would be inside the insulated envelope of our homes, but our building standards are not there. So where you can affect energy efficiency is in improving the impermeability of your insulation as it currently exists. If you're going for energy efficiency, slightly lowering the ambient temperature of your attic in the summer heat is just not an effective solution. Spend that money instead on fully sealing all the holes around joints and fixtures that are currently leaking air between your living space ceiling and your attic, and improving the R value of your attic insulation.
I don't know if what I'm talking about applies to your house, but if so, check out this Matt Risinger video for a lot more detail.