Confirm what stays and what changes
Give the contractor the furnace, indoor coil, outdoor unit, and thermostat model numbers, plus installation and warranty records. Ask which components can stay, which must change, and the manufacturer-supported basis for that combination.
Request the matched system documentation and required indoor airflow. Ask whether the existing blower and air distribution can support the proposed heat pump in both heating and cooling. Do not assume a furnace that heats well automatically satisfies the new equipment's requirements.
If a proposed combination lacks clear manufacturer support, we would compare a different matched option rather than forcing reuse solely because the furnace is young.
Make the furnace's role clear
Ask when the heat pump runs and when the furnace takes over. Request the heating-load assessment, cold-weather output, controls sequence, and reason for any switchover setting.
Keeping a furnace should serve a purpose you understand: compatible backup, operating-cost flexibility, or a staged equipment plan. Ask whether the proposal meets your desired comfort and what could change the recommendation.
Have the contractor explain the required controls and verify the final operation. Leave wiring and installer settings to the qualified technician.
Read the complete project and warranty terms
Request a scope covering the indoor equipment, outdoor location, refrigerant connections, drainage, electrical work, controls, permits, commissioning (startup checks that verify the installed system operates as intended), and any separately assigned corrections. Professional commissioning guidance. Ask who owns work outside the equipment install.
Ask the manufacturers or qualified provider how the change affects the existing furnace warranty and the new system's coverage. Request separate labor and parts terms in writing. Equipment matching and an incentive's qualifying combination are questions to verify, not interchangeable approvals.
Also compare the full price of reuse with a complete replacement option if significant changes are needed. The lower equipment price may not be the lower complete project price.
Your next step is a proposal listing every retained and replaced model with a supported match, controls plan, and warranty explanation. We would keep the furnace when that complete plan makes sense, not replace it simply to make the quote easier.