Don't count in it.....even if you have no ventilation.My coop is insulated. I’m hoping these heaters with produce just enough heat to keep it above freezing so my water does not freeze. That is the only reason I’m heating the coop. I have a horizontal nipple watering system and am trying these heaters first to see if they will work.
The tube between bucket and pipe will probably freeze first.
Heat the water, not the coop, for freeze free water in winter.