Ask which limit the setting represents

The capacity question is, “When does this heat pump need help to meet this home's demand?” The cost question is, “When would the furnace be cheaper to deliver the required heat?” Those results need not match.

Ask for the exact matched model data, calculated home heat need, local design condition, and current gas and electric tariff used. Request the written comparison and the reason for the proposed setting. A customary number can be a starting point for discussion, but it should not replace this assessment.

Have the controls explained as a system

Ask whether the quoted temperature is a heat-pump lockout (a setting that stops the heat pump), a furnace enable point (a setting that allows the furnace to run), or a comfort setting. Those terms do not by themselves establish when each unit will run. For example, Honeywell's T10 and T10+ instructions describe heat-pump lockout and backup-heat operation that depend on the configured system and controls. Your technician should explain the sequence for your exact models. Honeywell T10 and T10+ control instructions. Ask how sensor readings, recovery from a lower thermostat setting, and fault conditions affect which equipment runs.

Have the technician check that the proposed sequence follows the exact equipment and control instructions. Do not change installer menus, jumper wires, or sensor settings to test a forum recommendation. A control change needs a qualified person to verify its effect.

We recommend prioritizing a reliable heating sequence, then optimizing cost within its supported limits. If the system is not keeping rooms warm, solve that performance problem before trying to save money with a different switch temperature.

Revisit the setting when the inputs change

Ask for a review if rates change, home improvements reduce heat loss, equipment changes, or actual operation differs from the forecast. Do not assume a setting chosen for an earlier furnace, tariff, or heat pump still fits.

After adjustment, request a record of the final settings and operating checks. Ask what you should observe in normal use and what warrants a return visit. The homeowner should have an explanation, not just a hidden menu value.

Your next step is a documented capacity-and-cost comparison for your installed system. That resolves why the recommendations differ and gives the technician a defensible basis for the final controls.