Estimate HVAC costs, energy use, equipment sizing, airflow, efficiency, filter schedules and indoor comfort with free HVAC calculators you can use without signing up.
These tools are designed to help homeowners and businesses understand common HVAC numbers before moving deeper into repair, replacement, efficiency or system-sizing research.
Search by tool name or filter the collection by cost, energy, sizing, airflow or maintenance.
Estimate a replacement cost range using system size, efficiency and project inputs.
Open Calculator → Cost & DecisionsEstimate a common AC repair range based on repair type and system factors.
Open Calculator → Cost & DecisionsCompare repair cost, age and replacement economics for an HVAC system.
Compare Options → HVAC SizingEstimate an initial HVAC system size using home size and basic building inputs.
Estimate HVAC Size → HVAC SizingEstimate heating or cooling capacity in BTUs from basic room or home information.
Calculate BTUs → Energy & EfficiencyCompare cooling efficiency and estimate the energy impact of a higher SEER2 system.
Compare SEER2 Savings → Energy & EfficiencyEstimate what an air conditioner may cost to operate over a selected period.
Estimate Running Cost → MaintenanceEstimate a practical filter replacement interval based on household conditions.
Estimate Filter Schedule → Energy & EfficiencyEstimate monthly heating and cooling electricity costs from equipment usage.
Estimate Monthly Cost → Energy & EfficiencyCalculate a cooling electricity estimate from power use, operating hours and utility rate.
Calculate Electricity Cost → Energy & EfficiencyEstimate operating costs for a furnace using fuel, efficiency and runtime assumptions.
Estimate Furnace Cost → Energy & EfficiencyEstimate heat pump operating costs from capacity, efficiency, runtime and electricity rate.
Estimate Heat Pump Cost → Cost & DecisionsEstimate a ductless mini-split project range using zones and equipment assumptions.
Estimate Mini Split Cost → Cost & DecisionsEstimate duct installation or replacement cost using home and project inputs.
Estimate Ductwork Cost → Energy & EfficiencyEstimate possible HVAC energy savings from thermostat temperature adjustments.
Estimate Savings → Energy & EfficiencyCompare purchase cost and estimated energy savings to calculate a simple payback period.
Calculate ROI → Cost & DecisionsEstimate how long an HVAC upgrade may take to recover through projected savings.
Calculate Payback → Energy & EfficiencyCompare common HVAC efficiency values and see the relative difference between systems.
Compare Efficiency → Cost & DecisionsCompare estimated operating costs for an older AC system and a newer efficient system.
Compare Old vs New → HVAC SizingConvert an estimated cooling load into an approximate HVAC tonnage range.
Calculate Tonnage → HVAC SizingEstimate the cooling or heating BTUs needed for an individual room.
Calculate Room BTUs → HVAC SizingEstimate an initial whole-home heating or cooling capacity requirement.
Calculate Home BTUs → Airflow & ComfortEstimate airflow in cubic feet per minute from basic HVAC sizing inputs.
Calculate CFM → Airflow & ComfortEstimate a starting duct size using airflow and basic duct-design assumptions.
Estimate Duct Size → Airflow & ComfortCalculate ACH using room volume and airflow information.
Calculate ACH → Airflow & ComfortEstimate filter face-area requirements from airflow and design assumptions.
Estimate Filter Size → Airflow & ComfortEstimate dehumidification capacity using space size and moisture conditions.
Estimate Dehumidifier Size → Airflow & ComfortEstimate whole-home humidifier capacity using home size and indoor conditions.
Estimate Humidifier Size →A calculator is most useful when it connects the number back to the HVAC problem, cost or service decision behind it.
Begin with a repair issue, cost question, efficiency concern or sizing need.
Enter the information you know and generate an informational estimate.
Use the result to understand the range, comparison or sizing implication.
Move into the relevant HVAC service, guide, cost page or local HVAC information.
Use the supporting HVAC sections to understand problems, pricing, services and system decisions.
Research common repair, replacement, installation and equipment cost topics.
Explore HVAC Costs →Start from symptoms such as warm air, leaks, noises, weak airflow or short cycling.
Explore HVAC Problems →Learn about efficiency, equipment life, maintenance and system comparisons.
Read HVAC Guides →Move from research into repair, replacement, maintenance or system-specific information.
Explore HVAC Services →Understand the factors that can affect an AC repair-versus-replacement decision.
Read the Guide →Learn what SEER2 ratings mean before using the efficiency and savings calculators.
Read SEER2 Guide →HVAC calculator outputs on this site are informational estimates only. Actual equipment sizing, repair pricing, installation cost, operating expense and system performance can vary based on the property, equipment, climate, contractor, utility rate and on-site conditions. Calculator results should not be treated as a contractor quote, engineering design or substitute for an on-site evaluation.
If a calculator points you toward repair, replacement, installation or another HVAC service, send the basic service and location information.