Question: Why do modern stoves have firebrick on the sides? The metal there is almost as thick as the baffle plate which is exposed to the full brunt. I was thinking that the heat transfer would be much better without brick on the side. That's how grandpa's stove was built, those designs had either bricks on the bottom (or sometimes a grate) but bare metal on the sides. This old stove also wasn't as "hungry" as ours while heating a similar space, but I bet it would be outlawed by EPA by now. Answer: -Bricks serve two purposes. They do protect the steel sides of the stove from excess temperatures. This was the primary purpose in pre-EPA stoves.However, in newer stoves they also serve to reflect heat inwards and make for a hotter burn. A hotter burn is a cleaner burn, so this is important in reducing pollution and meeting EPA standards.The same size fire brick available in the masonry yard should do fine.Lastly, a newer stove should get more heat from less wood than one from grandads time. They are now 60-75% efficient as opposed to 35-45% for older models.