Stupid dimmer switches

So... I have (had) one of those 4" inline duct fans pulling heat out and a medium sized fan circulating air in the bottom of my filing cabinet, both of which were run to the dial type dimmer switches (to slow them down). So, after about a month or two the inline fan wasn't running, cabinet was almost to 100 degrees. The dimmer for that one was hot to touch, so I removed it and rewired the fan to run without it. Almost the very next day, my circulation fan (also run to a dimmer switch) was dead. I rewired it to run without the switch, but this time the fan itself was dead.
So what did I do wrong? The store "experts" said neither fan would be pulling enough amps to cause a problem, but I am not an electrician (but yes, I had the pos and ground correct, lol).
Anyway, now for the moment my exhaust fan is running full speed, while the bottom of my cab is just using a passive intake hole. But now I can't keep my temps up (max has been 68-70). The only way I can hit 78-79 is if I unplug the ehaust fan (which I'm leary of doing (I've reworked my cabinet, removing an upper shelf/seedling area, so temps don't get up to 100 now, more like 78 with no exhaust).
I'm in my 5th or 6th week of flowering, running 4) 100 watt soft CFL's under a homemade reflector. I'm thinking about building a second reflector with 4 more 100 watters (maybe cools, this time, best of both worlds) this weekend and shifting the plant in the middle of the two. But I still need to pickup another circulating fan. Crap. Kaching, kaching $$$$

I would think (possibly) that the amp draw on the fans are to much for the dimmer.. Dimmers like that are meant for single incandescent fixtures

Were these for fans? they make different switches for fans and lights, the light ones are for much less power draw than the ones for ceiling fans.

I'm pretty sure they were light ones, hence they're dead. Last time I listen to a Home Depot employee. Wasn't aware they had fan ones as well. Chock it up to noob mistakeage.

No man common mistake, i do things like this for a living, i can not make that mistake or i have to come back for free to replace it. Just look at the package it will say if it is for a fan or a light, and often how much power it can handle. Never listen to the HD employee in the electric department, ever!!!