U.S. Department of Energy - Energy Efficiency and Renewable Energy

Federal Energy Management Program – Energy-Efficient Products

Energy Cost Calculator for Commercial Unitary Air Conditioner (Rooftops)


This FEMP energy cost calculator compares the energy costs for your selection with the energy cost for the FEMP recommended rooftop units for various energy costs, efficiency levels, size variations, and hours of operation.
INPUT SECTION
Input the following data (if any parameter is missing, calculator will set it to the default value). Defaults
Condenser Type    Air Source
Capacity    tons 10 tons
Energy Efficiency Ratio    EER 10.3 EER
Annual Hours of Operation    hours 1500 hours
Energy Cost $ per kWh $0.06 per kWh
Quantity of Air-Conditioners to be Purchased    unit(s) 1 unit
OUTPUT SECTION
Performance
per Air-Conditioner		 Your
Choice		 Base
Model		 FEMP Recommended
Level		 Best
Available
Energy Efficiency Ratio   EER         
Annual Energy Use    kWh         
Annual Energy Cost $ $ $ $
Lifetime Energy Cost $ $ $ $
Lifetime Energy Cost Savings $ $ $ $
Performance
for Air-Conditioner(s)		 Your
Choice		 Base
Model		 FEMP Recommended
Level		 Best
Available
Energy Efficiency Ratio    EER         
Total Annual Energy Use for Air-Conditioner(s)    kWh         
Annual Energy Cost $ $ $ $
Lifetime Energy Cost $ $ $ $
Lifetime Energy Cost Savings $ $ $ $

Your selection of a(n) ton rooftop unit will have a $ energy cost savings per air-conditioner (over its estimated 15 year life expectancy compared to the base model).

Assumptions
  • "Base model" has an efficiency that just meets the national minimum standard for that capacity.
  • Lifetime Energy Cost is the sum of the discounted value of annual energy costs based on assumed air conditioner life of 15 years. Future electricity price trends and a discount rate of 4.1% are based on Federal guidelines.
  • $0.06/kWh is the Federal average electricity price in the U.S.
Disclaimer
This cost calculator is a screening tool that estimates a product's lifetime energy cost savings at various efficiency levels. Maintenance and installation costs do not vary significantly among the same product having different efficiencies; so, these costs are not included in this calculator tool. For a detailed life-cycle cost analysis, FEMP has developed a tool called Building Life-Cycle Cost (BLCC). This downloadable tool allows the user to vary interest rates, installation costs, maintenance costs, salvage values, and life expectancy for a product or an entire energy project.