Also there different types out there, from ceramic to oil filled and even infrared (
DeLonghi EW7507EB. The DeLonghi is an oil filled radiator heater with many features to make it easy to warm up the temperature in your grow tent.. This heater works for small grow tents but it's also ideal to use in large rooms, especially those that need constant heat.
A 1kw oil rad would better both better and cheaper to run. I've got a small 700w oil rad which is more than enough to keep temps up if needed.