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@Intheswamp had some excellent points/thought provokers.
You aren't even 160 km north of me and my chickens are fine with no heat. BUT their coop is a converted horse stall in an ancient barn so there is plenty of air movement without any part of the coop being exposed to the weather. Thus you will have to work harder to make sure there is ventilation without air and snow blowing on the birds on the roost. Snow is a very good insulator, your issue will be in keeping it out of the coop while maintaining adequate open ventilation ports.
Still, unfrozen winter water is a big deal for me and anyone else that lives where it goes much below freezing. I ASSUME that white PVC pipe connected to the black pipe is the water source? I guarantee you, aquarium heater in the vertical pipe or no, those pipes will be solid ice when it gets cold, and cold in this case means likely -5C or even warmer given the distance from the white pipe to the heater. You will have cracked PVC pipe and when it thaws, water running everywhere.
You can search this site for winter water ideas. When it gets down to those -20C, -30C temps no heated water dish is going to keep up. What I did was build a water pipe with nipples (*) built into the underside of the 4' long nest box (maintenance mistake there) insulated by rigid foam. That is connected by clear tubing to a 5 gallon Igloo drink cooler ('self insulated') directly on the other side of the coop wall (outside the coop so easy access to add water). The cooler is in a cheesy plywood box that also has some rigid insulation though not all that well insulated. Inside the cooler is a really small reptile waterfall pump that continuously circulates the water through the tubing from one end of the pipe and back to the cooler from the other end. I have a 250W stock tank heater in the cooler that keeps the nipples from freezing down to about -10C. It is self regulating, meaning it turns itself on and off based on the water temp. Below that I turn on an aquarium heater set to about 24C and that usually keeps the nipples from freezing down to probably -30C.
* I have saddle nipples but people have seemed to find that the horizontal nipples are less likely to freeze. If I ever rework the system, I'll try the horizontal nipples, there is a lot of distance between the pin and the pipe in the saddle nipples which makes it harder to keep warm water in contact with the pins.
Maybe you need a trap door in the porch floor for easy access to your chickens
Good luck!