Ventilation

I am building a grow box right now that will be put outside in my garage.
I can easily cut holes and maneuvers thinks for optimal conditions. I was wondering what was recommended for ventilations.

I have read that is it a good idea to have an intake fan to suck air in and a exhaust fan to blow things out. All of this if fine for the summer spring and fall but in the winter we get temperatures as low as -40C with all this air movement thats gonna freeze my plants.

Any suggestion on what i should do to keep it warm and offer fresh air in the winter?

My grow box will be insulated.

You might be interested in this.

You definitely need air circulation for your plants. The more fresh air they get the better they feel!

they have heater fans that you can probably switch out with your intake fan when winter comes and for your exhaust find a carbon filter to run it through to help control smell

yepper.....thermostat kit....way to go.....and a small space heater...one thats safe...i got one for a baby's room....shuts off if it gets covered by something, or if it tips over.i used it all last winter at night after the lights went off