Controlling a 1000W radiant heating element with dimmers
You can certainly use a light dimmer for this application. 

Caveats- consumer products may not be conservatively rated, so pick something industrial or over-rate it significantly. 

Consumer light dimmers do not go (smoothly) all the way down to zero- they typically "snap on" to a fraction of full power. If your IR elements are not grossly over-rated that should not be a problem. 

I recently did this for heating a cryogenic apparatus using a router speed control- we had to open the control and adjust the minimum power level trimpot. The control allowed manual adjustment of the power going to a bunch of industrial heaters. 

If you want a measure of the power going to the heaters, it would be best to use a "true RMS" voltmeter.