Our principle: ranges, not mystery numbers
HVAC Cost Lab is designed for early-stage homeowner planning. We publish the assumptions behind the tools and avoid presenting a calculator result as a contractor quote.
2026 cost benchmarks used in this build
The initial calculator baselines use published 2026 U.S. consumer cost research as broad national anchors. The live calculator then applies transparent planning factors for home size, efficiency, installation complexity and broad ZIP-region cost differences.
| System | Initial national baseline used |
|---|---|
| HVAC replacement | $5,000 low / $7,500 typical / $12,500 high |
| Central AC | $3,887 / $5,978 / $8,073 |
| Furnace | $2,823 / $4,814 / $6,896 |
| Air-source heat pump | $4,236 / $6,087 / $7,942 |
| Common mini-split project | $2,000 / $3,000 / $5,000; zone tool uses published multi-zone ranges |
Energy formulas
SEER2 is seasonal cooling output in Btu divided by seasonal electrical energy in watt-hours. Our running-cost and savings tools use that relationship as a simplified planning model: approximate watts = cooling capacity (Btu/h) ÷ efficiency rating. Actual systems operate at changing loads and conditions, so the result is an estimate rather than a utility-bill prediction.
HVAC sizing
The BTU tool deliberately labels itself a simplified planning estimate. ACCA Manual J is the ANSI-recognized residential load-calculation standard and includes far more variables than square footage. Final system sizing should use an appropriate Manual J calculation and equipment-selection process.
Sources reviewed for this version
ACCA — Manual J Residential Load Calculation
ENERGY STAR — SEER2, EER2, AFUE definitions
U.S. Department of Energy — SEER2 and energy-cost methodology context
Angi — 2026 HVAC replacement cost data
Angi — 2026 AC replacement cost data