I think you'll be fine
I can't say for the OP, but for me, the answer is pretty simple. I get robbed at the lFS! I like to buy good quality heaters and I am very particular about the features on my heaters so those I find locally are not what I want. My store credit is about the only reason I shop local. If it becomes a question of letting the credit expire or buying something, I do buy equipment locally.Heaters are not that much, why not just go to your local fish store and buy a new one?
people mainly add heater for the fishes comfort. plants can benefit also because they grow better at warm temps.Thats a new thing for me to see planted tanks having heaters.
So what is the minimum temperature we are taking about without heater in the room?