Most talk about service contracts starts with what they cover. This walk starts later, at the moment something breaks and you pick up the phone. A plan only does its job if that call goes the way the paper says it will. Read the claim path before you sign, while you still have a choice.
Find the claim sequence in the paper
Open the contract and find the section that describes what happens when you report a failure. Look for the order of steps. Does the plan require you to call a number first, or to log the problem online? Must someone inspect the equipment before any repair is approved? Write the steps on your clipboard in the order they appear. If the order is not written down anywhere, that is the first question to ask.
Who picks the technician
Some plans send a technician they select. Others let you use your own local service company and then ask that company to bill the plan. Ask which arrangement applies. Then ask whether the technician has to be on a list, whether you can use your regular service company, and what happens if the assigned technician cannot arrive within the time the plan states. Get each answer in writing, because a verbal answer does not help you at the door.
Who approves the repair
Ask whether the plan must approve a repair before work starts, and how that approval reaches the technician. Ask how long approval usually takes and whether urgent work may begin while approval is pending. Ask whether approval covers the parts the plan names, the labor, or both. These are the points where a repair stalls, so they belong on your list before you commit.
What you may pay at the door
Many plans include a trip charge or a service fee that you pay the technician at the visit. Find out whether such a fee exists, what the contract calls it, and whether it applies to every visit or only some. Also check whether you pay anything at all for a repair the plan approves, or whether the plan pays the shop directly. Do not sign until you can state, in a single sentence, what you hand over at the door.
Who holds the paperwork
Ask for copies of the claim forms and any approval letter the plan issues. Ask how a claim is recorded and how you obtain a copy of that record. Keep these with the contract and with your equipment file. When a question comes up later, the paper trail settles it more reliably than memory does.
What to ask before you sign
Write the questions down and put them to the plan, not only to the person selling it. Ask what you call first, who approves the work, who chooses the technician, what is due at the visit, how long approval takes, and where each answer is written. Ask for the answers in writing. If the plan cannot answer these in writing, that gap is worth knowing before you pay anything.
Check the figures in the tables
This page does not list prices, fees, or contract terms, and it does not describe what any company's plan includes. For published planning figures on each system, use the system pages. The gas furnace page is a starting point for a furnace, and the heat pump page covers a heat pump. Use those figures to decide when a contract is worth weighing, then bring the claim-path questions to the plan.