Put the features in separate columns
Ask for the exact model, its heat output, AFUE, heating stages, blower features, and compatible thermostat. A two-stage gas furnace has lower and higher heating outputs. A single-stage one has one output when firing. Do not assume either quote includes a variable-speed blower. Carrier's staging explanation.
Then ask why each model fits your calculated home heating need. Efficiency and staging do not repair an unsuitable size.
We recommend comparing both options against the same concern. If your main concern is loud or abrupt operation, ask what measured or observed condition supports a staging benefit. If your main concern is fuel use, request an operating-cost estimate with visible assumptions. If one room is cold, ask what explains that room before treating either feature as its cure.
Compare the whole installation
Request the complete scope for each choice, including venting, condensate handling if required, controls, permits, and work by other trades. Ask which existing items will remain and why they are suitable.
A lower equipment price can disappear in a more involved installation. A higher quote can also include work missing from the other quote. You need the totals and exclusions in the same form before comparing.
Ask how heating operation, airflow, and controls will be checked after the work. A product specification describes available capability; setup and verified operation show how the installed equipment is using it.
Decide what the extra money buys
Ask for a suitable baseline option. Then identify the additional price for fuel-efficiency features, comfort features, and installation changes. You do not need to assign every dollar perfectly, but the contractor should explain the main reasons for the difference.
We would avoid a choice justified only by “two-stage is better” or “high efficiency pays for itself.” A sound recommendation should say which benefit fits your concern, which conditions affect it, and what remains unresolved.
Your next action is to request that side-by-side comparison with exact model data and full project prices. Choose the tradeoff you can explain in your own words and afford, with the home's sizing and installation needs resolved first.