How the tools work

Methodology

HVAC Cost Lab creates planning estimates, not contractor quotes or professional load calculations. Each tool uses a short, visible formula so readers can understand what moves the result.

Our calculation standard

• Prefer user-entered utility prices, project scope, measured energy, and equipment data over hidden national averages.
• Label every shortcut and distinguish preliminary sizing from ACCA Manual J/S/D design.
• Use ranges when local labor, equipment, or site conditions create material uncertainty.
• Keep energy, purchase price, maintenance, comfort, and risk as separate decision factors.
• Round outputs to avoid false precision.

Cost estimates

The replacement calculator uses transparent baseline allowances and uncertainty bands. It intentionally does not publish a single universal installed price because regional labor, permitting, access, electrical scope, ductwork, equipment availability, and contractor overhead differ.

Energy estimates

Energy calculators use standard unit conversions and user-provided rates. Seasonal equipment performance is simplified and should be replaced with certified model data and local design calculations when a decision depends on a narrow margin.

Primary references

• U.S. Department of Energy — Heating & Cooling
• ENERGY STAR — Heating and Cooling
• U.S. Energy Information Administration — Residential Energy Consumption Survey
• U.S. Energy Information Administration — Energy use in homes
• Air-Conditioning, Heating, and Refrigeration Institute — Directory
• ACCA — Residential system design information

Review cycle

Core assumptions are reviewed at least quarterly and whenever a major federal standard, test procedure, reference dataset, or code-related source changes. The status page records the current review date and known limitations.