615 HVAC Questions, Answered Clearly

Normalize the comparison: system type, capacity, rated performance, staging/modulation, controls, duct/electrical scope, permits, commissioning, warranty and total installed price. Brand alone does not make two scopes equivalent.

The difference may come from equipment level, scope, permits, duct/electrical work, labor, warranty or omitted items. Compare line by line before concluding the lower number represents the same project.

Not automatically. Confirm that the bids cover the same system design, installation scope, permits, testing and warranty before comparing price.

For a replacement where sizing is in question or the home has comfort/load changes, a proper load calculation is the strongest basis for capacity selection instead of simply copying the old tonnage.

The old system may have been oversized or the building may have changed. Insulation, windows, additions, ductwork and current design conditions should inform the new selection.

Yes. Model numbers make it possible to verify the actual equipment, efficiency, capacity, warranty and matched combination rather than relying on broad marketing descriptions.

Yes. Permit responsibility should be explicit so the customer knows who applies, pays, schedules inspection and closes the permit.

Yes. New equipment should be tested after installation; a quote that omits any mention of startup, airflow or performance verification deserves clarification.

Ask the warranty length, what labor is covered, exclusions, maintenance requirements, transferability and how callbacks are handled. Get the terms in writing.

Confirm parts coverage, registration requirements, compressor/heat-exchanger terms where applicable and who will submit registration. Use the exact model's current warranty document.

It is reasonable to ask who will perform the work and who is responsible for permits, workmanship and warranty callbacks. The answer should be clear before installation begins.

Yes. California customers can verify license status and classification through CSLB. The company name on the proposal should match the contracting entity doing the work.

Confirm the qualifying equipment combination, utility territory, participating-contractor requirement, permit/HERS steps, whether the incentive is reserved or post-paid, and what happens if program funding changes.

Only when the program structure and contractor process support it. Otherwise rebates may be paid later and remain contingent on eligibility, inspections or funding; the proposal should explain this clearly.

Separating required code/system work from optional comfort or efficiency upgrades lets the homeowner compare choices without mistaking an upgrade for a mandatory repair.

It should mean the customer sees the price and defined scope before approving work. It does not eliminate the need to explain how additional unforeseen work will be handled if new conditions are discovered.

A second opinion is an independent review of a major diagnosis or replacement recommendation. The value is highest when the second contractor receives the first findings and performs its own verification rather than simply underbidding.

For a major system investment, comparing multiple written scopes can help reveal differences in sizing, duct/electrical work, equipment, warranty and permit handling. Compare equivalent scope, not just total price.

Ask how to use the thermostat, where/when to change filters, what normal operation sounds like, what maintenance is expected, how warranty registration works and where permit/commissioning documents are stored.