Yo, just a snippet from the internet for ya. I guess you do need a little heat to start things off in the Bag.
ExHale Homegrown CO2 Bags provide a continuous supply of carbon dioxide with no need to refill bottles or use expensive regulators, generators and monitors. The power of the product lies in the mycelial mass, which is growing on organic matter inside the cultivator, and the one-way breather patch located on the bag. Supplies up to 1500 ppm CO2, depending upon room size and ventilation for up to 6 months. Easy to use, just hang slightly above the height of the plants in your grow space. Each bag will provide 4-6 plants with a continuous shower of CO2. No need to turn it on or off -- simply leave it alone to do its job!
Simply hang the bag above your plants (CO2 is heavier than air, so it will fall) and keep the air moving in your grow space with a fan. The moving air will keep the CO2 from staying near the floor where your plants can't reach it. This item works best for your indoor/hydroponic garden when the room is small and/or recirculates the air within it. Also, periodically turning your fan off will help the CO2 ppm increase in your room to give your plants a boost. And remember, plants can be comfortable in higher temperatures when the CO2 ppm is relatively high.