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Estimate daily HVAC runtime based on system capacity, average electrical draw, thermostat setpoint difference, outdoor climate severity, and home insulation quality.

Estimate seasonal heating output and electricity use for a heat pump using HSPF, heating capacity, runtime, and electricity rate. HSPF is the total seasonal heating output in BTU divided by total electricity input in watt-hours.

Estimate HVAC electricity use in kilowatt-hours based on system power, daily runtime, seasonal usage, equipment efficiency, and climate demand.

Estimate HVAC duty cycle as the percentage of time a heating or cooling system runs during an observation period based on total runtime and cycle behavior.

Calculate refrigerant superheat by subtracting the saturated evaporator temperature from the measured suction line temperature. This helps verify proper refrigerant charge and evaporator performance in HVAC systems.

Calculate refrigerant subcooling by subtracting the measured liquid line temperature from the condensing saturation temperature. This helps evaluate whether a refrigeration or air conditioning system has the proper liquid refrigerant cooling below saturation.

Calculate either superheat or subcooling from measured refrigerant temperatures and pressures. Enter the saturated temperature corresponding to the measured pressure along with the actual line temperature to find the temperature difference.

Estimate the air conditioning temperature split by subtracting the supply air temperature from the return air temperature. This helps evaluate basic cooling performance across the evaporator coil under typical operating conditions.

Calculate the sensible heat ratio (SHR) for an HVAC process using sensible cooling load and latent cooling load. SHR indicates the fraction of total cooling devoted to sensible heat removal.

Calculate the specific enthalpy of moist air for HVAC applications using dry-bulb temperature, relative humidity, and altitude. The result estimates air enthalpy in BTU/lb of dry air based on standard psychrometric relationships.

Calculate the coefficient of performance (COP) for an HVAC system using heating or cooling output and electrical power input. COP is the ratio of useful thermal output to electrical energy consumed.

Estimate HVAC system efficiency using cooling output, electrical power use, seasonal runtime, climate factor, and system age. This calculator approximates effective seasonal efficiency as adjusted BTU output per watt-hour consumed.

Calculate the Energy Efficiency Ratio (EER) of an air conditioner or cooling system using cooling capacity and electrical power input. EER equals cooling output in BTU per hour divided by power input in watts.

Estimate annual cooling energy cost and yearly savings when upgrading to a higher SEER2-rated air conditioner or heat pump. SEER2 is the seasonal energy efficiency ratio under updated testing standards; higher values generally mean lower electricity use for the same cooling output.

Estimate an air conditioner’s SEER rating from cooling output and electricity use, and compare annual operating cost based on local usage and electricity price.

Estimate annual cooling cost savings when upgrading from an existing air conditioner to a higher-SEER system based on capacity, runtime, electricity rate, and system efficiency.

Estimate monthly HVAC operating cost based on system size, runtime, electricity rate, system efficiency, and climate demand.

Estimate the electricity cost to run an HVAC system based on unit power draw, daily runtime, number of days used, local electricity rate, and system efficiency factor.

Estimate HVAC energy consumption and operating cost based on system size, runtime, efficiency, electricity rate, and seasonal demand.

Estimate annual energy cost savings from upgrading or optimizing an HVAC system based on conditioned area, current annual HVAC energy cost, system efficiency improvement, climate impact, and annual operating hours.

Estimate the required fresh air ventilation rate in CFM based on floor area, ceiling height, target air changes per hour, number of occupants, and activity level.

Estimate the airflow a fan should provide in cubic feet per minute (CFM) based on room size, ceiling height, desired air changes per hour, and ventilation efficiency.

Calculate air changes per hour (ACH) using room dimensions and airflow. ACH estimates how many times the total air volume in a room is replaced each hour.

Estimate the airflow in CFM required for a supply or return register based on room size, ceiling height, ventilation quality, and room usage. This helps size a register for general residential airflow planning.

Estimate the recommended attic fan airflow in CFM based on attic floor area, attic height, roof pitch, climate heat load, and sun exposure. This calculator uses a baseline air-exchange approach with adjustment factors for attic conditions.

Estimate the recommended whole house fan airflow in CFM based on home floor area, ceiling height, desired air changes per hour, and a climate/ventilation factor.

Estimate the recommended range hood airflow in CFM based on cooktop width, stove type, cooking style, and duct run length. This calculator provides a practical sizing estimate for residential kitchen ventilation.

Estimate the recommended kitchen range hood airflow in CFM based on cooktop width, cooking surface type, cooking intensity, hood mounting style, and duct length.

Estimate the recommended bathroom exhaust fan capacity in CFM based on room dimensions, ceiling height, and how many times per hour you want the air exchanged.

Estimate the required exhaust fan airflow in CFM based on room dimensions, desired air changes per hour, and ventilation effectiveness.