Yes mate it is upstairs in house I would say it's around 12 degrees in there as there is no heating so it isn't too warm.? My basement is 5 degrees lol.. my bedroom is around 10-12 I have inline from basement tho ?If the tent is in a basement you could prolly use that 1000. ( I'm assuming basement temps are 5 to 10 degrees less then your upstairs room temps. )
If that tent is UPSTAIRS Id use a 600.