An appliance's fuel and power source affects which parts wear, which trade work is needed, and which parts of a contract need a second look. A gas water heater and an electric one can carry the same label on a sales form and still ask different things of the contract.
List each covered appliance by its fuel
Write one line for each appliance in the home you plan to cover, and name its fuel or power source beside it. Typical entries are gas or electric water heaters, gas or electric ranges, gas, oil, or electric heating, heat pumps, and electric well pumps. Keep the list beside the contract as you read it.
Check the fuel side of the form
For each gas or oil appliance, check whether the contract covers the unit only or also the connection, the venting, the controls, and the fuel supply lines. Many forms draw the line in a different place for each fuel. Mark where the line falls for each appliance on your list. A line you cannot place is a question for the seller.
Ask who may do the work
Gas and oil work usually falls under licensing rules set by the state or a local body. Ask whether the provider sends technicians licensed for the fuel type in your area, and whether a contract repair will be done by a licensed person. This guide has not read the licensing rule for every state. Check the licensing body in your state before you rely on the answer.
Ask about the supply you do not own
An electric appliance depends on the home's power, and a gas appliance depends on the supply line and the meter. Ask whether the contract excludes damage caused by power surges, supply pressure, or the utility's own equipment. Any such exclusion sits in the form, so find it there.
Compare the list with the contract, not the sales sheet
Set your list beside the contract's appliance schedule. Where the schedule names an appliance you do not have, or leaves out one you do, stop and ask for a corrected schedule before you pay. A schedule built for a different home is a sizing error, and it is easy to miss when the sales sheet looks complete.