Start with the concern you would pay to improve
Are you trying to reduce noticeable starts and stops, address a noise complaint, or replace failed equipment within a tight budget? Tell the contractor which matters most.
Ask why the lower stage would be useful in your home and what controls are needed to use it. If the house has a recurring cold room, ask whether the cause has been assessed separately. Buying two-stage equipment is not proof that the troublesome room will become comfortable.
A suitable single-stage option can still be a reasonable choice when it fits the home and budget. An upgrade becomes easier to judge when it addresses a concern you actually have.
Make the five-year comparison honest
Ask for the additional installed price over the suitable baseline. Include any thermostat, electrical, vent, or other project changes. Compare the written warranty, registration conditions where applicable, and labor coverage.
If a bidder gives a savings estimate, ask what differs between the models. A change in AFUE is not the same as a change in staging. DOE explains AFUE as a fuel-efficiency measure, with fan electricity and air-distribution losses outside that rating. DOE efficiency explanation.
Ask for estimated annual operating cost, the assumptions behind it, and the result over your possible ownership period. Keep unconfirmed rebates or resale premiums out of the money you count on. If a financing charge applies, include it in the comparison.
You may choose the upgrade even without a short payback because its comfort features matter to you. That is a valid personal decision. It should be clear rather than disguised as a guaranteed financial return.
Consider the support you would leave behind
Ask what documentation, owner instructions, and warranty information would pass to a future owner. Transferability must come from the actual terms, not a sales assumption.
Also consider whether spending the difference on another confirmed home issue would better address your priorities. There is no need to buy every available feature to make a sound replacement decision.
Your next action is to request the suitable baseline and upgraded model with the extra total price, the specific expected comfort benefit, and any operating-cost estimate kept separate. Then decide what that benefit is worth for the years you expect to use it.