I have a cast iron stove. It heats and cools off quick. I am looking to find a way to retain more heat. I was thinking of adding a 1 inch think piece of granite stone of the top of the stove to help retain heat. I am not sure if this would be a good or bad thing to do. It seems good. But, it will change the performance of the stove. Has anyone tried it and if so how has it helped or hurt?