The appearance, are

Because if they have in the room, it is quite unpleasant to be in the room. Standard batteries, from any material, simply supply heat to the room by radiation. Aluminum heating radiators are very similar to convectors, so if you need to replace old batteries, or rather convectors, the best way out will be replaced with aluminum heating radiators. Their functionality, and the appearance, are largely similar to each other. Carefully study the market of these devices, all manufacturing companies.