Economizer Savings Calculator

Estimate energy and cost savings from an HVAC economizer by comparing mechanical cooling hours to free-cooling hours.

System Cooling Capacity

tons

Annual Cooling Hours

hours

Electric Rate

$/kWh

Economizer Hours

hours

ASHRAE 90.1 §6.5.1: economizer required >54,000 BTU/hr; hours: dry/cool climates 1,500–3,000 hr/yr; SE 500–800 hr

Compressor Power Draw

Tab to move between fields

Annual Savings with Economizer

$1,440.00

≈ 11 pairs of sneakers

Simple Payback Period

2.8 years

Annual Cooling Cost (No Economizer)$3,600.00

Annual kWh Saved12,000 kWh

How to Use This Calculator

Enter System Cooling Capacity, Annual Cooling Hours, and Electric Rate.
Set Economizer Hours and Compressor Power Draw.
Review Annual Savings with Economizer ($) and Simple Payback Period (years).
Use Annual Cooling Cost (No Economizer) ($) and Annual kWh Saved to inform your decision.

How the result changes with Electric Rate

Electric Rate	Annual Savings with Economizer	Simple Payback Period
0.11	$1,308.00	3.1 years
0.36	$4,272.00	0.9 years
0.65	$7,836.00	0.5 years
0.9	$10,812.00	0.4 years

System Cooling Capacity: Total cooling capacity of the HVAC system in refrigeration tons.
Annual Cooling Hours: Total hours per year that mechanical cooling is needed without an economizer.
Electric Rate: Average electricity cost per kilowatt-hour.
Economizer Hours: Estimated hours when outdoor conditions allow free cooling via economizer per ASHRAE 90.1 §6.5.1 requirements. ASHRAE 90.1 requires economizers for systems >54,000 BTU/hr in most US climate zones. Hours vary: cool-dry climates 1,500–3,000 hr; humid SE 500–800 hr.
Compressor Power Draw: Total electrical power draw of the compressor(s) during normal cooling operation.

Identify Input Parameters
4 parameters
System Cooling Capacity = 20, Annual Cooling Hours = 2000, Electric Rate = 0.12, Economizer Hours = 800 = 5 input(s) provided
Calculate Annual Savings with Economizer
Annual Savings with Economizer
1440 = $1,440
Calculate Simple Payback Period
Simple Payback Period
2.8 = 2.8
Calculate Annual Cooling Cost
Annual Cooling Cost
3600 = $3,600
Calculate Annual kWh Saved
12000 = 12000