A. O. Smith offers many different sizes of natural gas and liquid propane water heaters to meet your home’s needs. Evaluating your happiness with your current hot water within your home will help determine what size of water heater is best for you. Also, understanding where you will be installing your new water heater and how much space you have available will help in deciding what size of water heater you should purchase. Consult our online XPERT Product Selector.