17.100 btu out put heater

[Ericst38]

I have a very well insulated greenhouse 1/4 poly on the outside then a 3inch gap for framing and lined on the inside with 5/8 poly and sealed and 5 inches of gravel on the floor i have a 60amp sevice to run a 5,000 watt,17,100 btu out put heater ,for my 10 x12 greenhouse . I was woundering what some other greenhouse growers think and will this work fine. This will be my first winter outside so i want to get it right. I also have keroscene back up heaters if any power goes out....