Cost & Research Methodology

Cost ranges

We use broad national planning bands informed by public program data, manufacturer requirements, market observations, and the scope typically included in residential proposals. There is no single federal HVAC price database, so we never present a national range as a local quote.

Ranges are reviewed when equipment standards, refrigerants, incentive programs, or significant market conditions change. Each cost page carries an updated date.

A range is assigned to a defined project—not just a product name. We ask whether it includes matched indoor and outdoor equipment, removal, normal materials, installation, startup, and the stated allowance for distribution or electrical work. Items that cannot be known from a browser remain exclusions or contingencies instead of being hidden inside a precise-looking result.

Calculator assumptions

Calculator results are scenario estimates. They use visible inputs and broad adjustment factors rather than hidden claims of precision. Results exclude unusual structural, environmental, access, code, or hazardous-material conditions unless explicitly stated.

The replacement calculator applies a capped floor-area cost factor, equipment-tier and market factors, and a separate duct allowance. The mini-split calculator separates the first zone from added zones, then applies area, equipment, access, and electrical assumptions. The repair-or-replace tool uses disclosed weights for age, repair share, repeat repairs, warranty, comfort, reliability, and energy-use signals.

All current constants, formulas, thresholds, rounding rules, and worked examples are published in the open planning model. The same central data file powers the live calculators and the research table so a model change cannot silently update one without the other.

Review and release process

Before a guide is published, we check whether it answers one distinct homeowner decision, whether major claims are supported by the source linked to them, whether estimates are labeled, whether internal links add context, and whether the safety boundary is proportional to the subject. Tables and examples are checked for internal arithmetic and contradictory assumptions.

Before a calculator release, we test minimum, typical, and maximum inputs; confirm that low results remain below high results; reproduce the documented examples; inspect mobile and keyboard use; and verify that unsupported precision is removed through broad bands and rounding. A release date and model version are recorded publicly.

Sources and corrections

We prefer the IRS, EPA, DOE, EIA, ENERGY STAR, state agencies, utilities, standards bodies, and official manufacturer documentation. If you identify a factual error, contact the editorial team with the page, claim, and supporting source so it can be reviewed.

A correction request should identify the URL, exact statement, observed conflict, and responsible source. Material changes to calculator logic are recorded in the model change log. Minor wording, accessibility, and broken-link repairs may be made without changing the substantive update date.