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Content Type:Q&A

Revised March 2013

Question:

Is there a tool that can calculate the difference in energy use between a heat pump with a Seasonal Energy Efficiency Ratio (SEER) of 12, compared to one with a SEER of 13?

Answer:

There are heat pump options with SEER of 20+ that you may also want to explore too.

But, for calculating the estimated energy saved for two equipment efficiency options, here are three good on-line tools:

  1. The Western Area Power Administration offers a Cooling System Calculator. First choose your area on the map, then click "Accept". On the next page, input the number of cooling hours, fuel cost, the type of systems you are comparing, the duct system type(s), and the SEER. Then click "See Results" for the comparison.


  2. ENERGY STAR provides another good tool that also includes heating mode of the heat pump. This Air Source Heat Pump Calculator allows for a comparative analysis between two units, and accounts for weather conditions in your area of interest. The Assess Your Home tool allows you to compare your home energy use to other homes across the nation.


  3. For a more detailed calculation of energy use, the U.S. Department of Energy offers the Home Energy Saver calculator, which is very easy to use. The Home Energy Saver (HES) uses a very sophisticated computer program, DOE-2, to calculate energy consumption for a typical house configuration. The program allows you to change the assumed values and to specify energy costs, house area, insulation levels, appliance efficiency, and virtually every other variable that affects building energy use – including heat pump efficiency in heating mode (measured by heating seasonal performance factor—HSPF) and cooling mode (measured by seasonal energy efficiency ratio—SEER). The calculation shows the annual energy use broken out by heating, cooling, water heating, major appliances, lighting, and minor appliances.

    You can also save your data inputs for later use. For example, I inputted data for a typical house with a heat pump of an efficiency of 11.31 (HSPF) and a SEER of 13 – and it was saved as session number 421955. If you go to the HES and input the session number, you will get the example house I did for Rapid City. If you click on "Describe Your House" on the left, you can change any of the parameters, such as the efficiency of the cooling system and see what difference it makes in energy use.

    When I ran the model with a cooling system SEER of 12, I got energy costs of $37/year. With the cooling system at an SEER of 13, cooling energy costs dropped to $35/year – so the SEER 13 unit saves about $2.00 per year according to the calculator, given the assumptions I made. This number will vary depending on the amount of cooling required in the house you are modeling.

    If you want to link to the HES calculator from your utility’s web page, you may do so; written permission is not required.

    The Lawrence Berkeley National Laboratory document The Home Energy Saver: Documentation of Calculation Methodology, Input Data, and Infrastructure provides additional technical information about the Home Energy Saver.



Topic: Heating/Cooling/Ventilation--Cooling Systems
Topic: Heating/Cooling/Ventilation--Heat Pumps - General
Topic: Heating/Cooling/Ventilation--Heat Pumps - Air Source
Sector: Residential
Sector: Commercial
Content Type: Q&A
Keywords: heat pumps, HES, air conditioning, AC
ID:  4018