Gas grills are fuelled by either propane or natural gas.
Propane is portable and comes in economically priced cylinders. The cylinder is easy to install, is refillable, and does not require an installation expert to hook up. What makes propane popular compared to natural gas is its portability. If you choose to get a new grill or rearrange your layout, this type of fuel is easy to manage.
Natural gas grills are similar to gas cooktops and ranges, and eliminate the inconvenience of having to swap out propane tanks. They are also cheaper to operate than propane and have an always-on connection. If you do not have a natural gas line running to your home, you will need a public utility and a contractor to install one. From there, a natural gas outlet can be installed on the side of your home, and you can run a hose from your grill to the outlet. Using this method can make it easier to move your grill if necessary. If you run a natural gas line directly to your grill, once it is installed, the grill cannot be moved. This choice is best saved for those who are building a dedicated outdoor kitchen, not just buying a grill.
The amount of heat a gas grill generates is measured in Btus (British thermal units). A basic grill will start out around 15,000 to 25,000 Btus. The higher you go with features and grill size, the higher your Btu rating will be. A high-end, built-in grill will likely produce up to 60,000 Btus or more.
Typical gas grills will have between one and four burners, although some higher end grills will have more. Burners control the amount of heat applied to the food. One burner provides less control than multiple burners, simply because multiple burners allow for both direct and indirect cooking. Many high end grills shape their burners in unique ways to maximize heat distribution and provide a more effective way to grill with indirect heat.
Propane gas grills are typically freestanding and do not need brick or ceramic surrounds, although they can be built into a custom enclosure. They come with a cabinet or a cart base. The cart is especially handy in locations with cold winters, where you'll want to move the grill inside for part of the year.
Natural gas grills can be freestanding or built-in. (Either way, they need to be close to the gas hookup.) Although they look like standard gas cooktops or rangetops, built-in grills should be installed in a stone, brick or other non-combustible enclosure. If the enclosure is made from combustible material, the grill will require a liner or surround. For a permanent outdoor kitchen, most homeowners choose a built-in grill.