Topics from the Power Line: Web tools available to calculate energy savings

Editor's note: The Energy Services Bulletin features real answers to real questions posed to our staff at the Energy Services Power Line. We hope you find it useful.

Question:

Do you have information on calculating the energy savings for air conditioners with various SEER (seasonal energy-efficiency rate) values and capacities? We need to calculate the energy savings from our utility's energy-efficiency rebate program.

Answer:

First, it is important to understand that if you are currently providing a rebate for air conditioners with a SEER of 13, there will be no savings. Units with 13 SEER are the minimum efficiency units that can be legally manufactured in the United States.

Here are two different Web-based calculators you can use to estimate the savings from going to higher SEER units:

• The Air Conditioning Cost Calculator, developed by Energy Experts at Washington State University, estimates air conditioner energy use based on the SEER and the number of cooling hours per year. It also allows you to estimate the savings from sealing leaks in ductwork located outside the insulated shell of the building. On average, these ducts lose 20 percent of the heating and cooling energy that the homeowner pays for, and duct sealing can be very cost effective.
  
  

• The Home Energy Saver (HES) provides a comprehensive picture of residential energy use beyond just cooling. Lawrence Berkeley National Laboratory developed the calculator for the U.S. Department of Energy to help homeowners make decisions about improving the energy efficiency of their homes.
  
  The calculations are performed by DOE2.1 – a program that has been under continuous development for more than 30 years. DOE2.1 is generally recognized as the most accurate and flexible program available for calculating energy use.
  
  The user provides some simple data on the home's location, insulation values and heating and cooling system efficiencies. HES then estimates the home's energy use based on the assumption of an older 1,800-sq.ft. house.

After the initial calculation, you can view the home's parameters, or change them by clicking on the link below the six boxes that give the energy consumption. If you choose to change them, you are given the option of changing insulation levels, heating system efficiency, fuel costs, etc.

Your customers may find the HES useful for other energy consumption calculations, too. Consumers as well as utilities can use the Web site for estimating the savings due to multiple energy-efficiency improvements in a residence.

Resources

Air Conditioning Cost Calculator

Energy Experts

Home Energy Saver

Lawrence Berkeley National Laboratory

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