Ceramic Heater work u think?

My grow is outside and temps will get below 0 so i keep the 150 watt hps light on all day to keep it warm in my box But can i get this to make it warmer?

http://www.petco.com/product/5003/Zoo-Med-Repticare-Ceramic-Infrared-Heat-Emitters.aspx

To help keep it warm??

Just go to walmart and get a $15 ceramic space heater. You'll have to put a thermometer in to monitor and spend some time getting the right setting, but then it will come on when temp falls to a certain point and shut off when it goes above that.

that's what I do. I keep the heater behind my fan so the fan spreads the heat and Illegal is right, you can adjust it fairly easily to dial in the temp.. then just keep an eye on them and you can make small adjustments to the heater to slightly rise or lower heat.

good luck im also having the same prob its dropping bellow zero now and will hit minus 30-40 this winter thats in celcius not farienhieght im in ther twise a day checking temps and adjusting my heater