Make the complaint specific
Write down which rooms feel wrong, when you notice it, and whether the problem occurs in heating, cooling, or both. Note thermostat location, open or closed room doors, and any changes to the home. A short record during ordinary use is useful; you do not need a week of precise measurements before asking for help.
Ask the contractor whether the problem is uneven delivery of air, different heat loss or gain between floors, the way the thermostat calls for heating, or another confirmed condition. Do not assume a furnace with a different motor resolves each possibility.
ACCA treats load, equipment selection, and air distribution as parts of the design. That is why the equipment choice needs to fit the home around it. ACCA design guidance.
Ask what the proposed upgrade would change
A useful explanation connects the variable-speed blower to your actual findings. Ask which operating behavior would change, what air delivery has been checked, and what the design still cannot resolve.
If a contractor proposes longer circulation or a particular control setup, request its purpose, compatible controls, and tradeoffs. More fan operation is not automatically the right answer for every complaint. Ask how the settings will be chosen and demonstrated after installation.
If air distribution or the home’s walls, windows, or insulation need other work, keep that scope visible. Confirm who would provide it and whether it is included in the project. An HVAC equipment recommendation does not imply MGI offers duct work or that one contractor handles every dependency.
Compare with a suitable simpler option
Ask for a comparison with equipment that also meets the home's heating and cooling needs. Then compare the full installed price, the specific feature you would use, the controls it requires, and the result it is intended to improve.
We would give more weight to a clear explanation of your troublesome rooms than to a general claim that variable-speed is always better. The upgrade may be worthwhile when the findings support its benefit. If a separate cause remains unaddressed, budget for that cause before expecting the furnace to fix it.
Your next action is to request a comfort assessment tied to the floors you notice, followed by a written explanation of what the proposed blower can improve and what still needs attention.