EER (energy efficiency ratio): This heat pump efficiency value represents the cooling efficiency of an air conditioner or heat pump. This value is a single rated condition which allows equipment from one manufacturer to be compared accurately to the equipment from another manufacturer. As seen in the diagram below the EER is a ratio that compares the amount of electrical energy used to produce a given amount of energy required for cooling.
SEER (seasonal energy efficiency ratio): The SEER is just like the EER with one important exception. The SEER value is a more realistic heat pump efficiency measurement. The EER is measured using one set of temperatures at an Air Conditioning, Heating and Refrigeration Institute (AHRI) and U.S. Department of Energy required 95 F outside air temperature. The SEER is measured using the total cooling energy required for an average cooling season, divided by the total electrical energy required during that season.
COP (coefficient of performance): The COP is a value that encompasses the purpose of the EER. There are two main differences. First, COP can be used for both heating and cooling efficiency measurements. Second, the COP is dimensionless. In other words, the heating or cooling energy units (Btu/hr, W, etc) are converted to match the electrical energy units (Btu/hr, W, etc) before dividing the two into a ratio.
HSPF (heating seasonal performance factor): The HSPF is the heating equivalent of the SEER. It is measured using the total heating energy required for an average heating season, divided by the total electrical energy required during that season. HSPF values are provided only for the heating portion of a heat pump.
For the purposes of this website, the two values that will receive the most focus for heat pump efficiency are SEER and HSPF. These values are most accurate in defining expected energy usage over a given season.
The approximate SEER can be calculated from the EER using the following formula:
SEER = EER/0.875
So what heat pump SEER/HSPF rating should you buy?
It depends on a few factors.
Below are two tables that can give you some guidance if you are wondering how what heat pump efficiency to purchase.
In the first table below, locate your Zone Climate number based on the state and region that you live.
If you live in Canada, your Zone Climate number is 1.
|Climate Zone by State and Region|
|Alabama - North||3|
|Alabama - South||5|
|Arizona - North||2|
|Arizona - South||4|
|Arkansas - North||3|
|Arkansas - South||4|
|California - North||1|
|California - North/Central||2|
|California - South/Central||3|
|California - South||4|
|Colorado - North||1|
|Colorado - South||2|
|Connecticut - East||1|
|Connecticut - West||2|
|Georgia - North||3|
|Georgia - South||4|
|Idaho - North||1|
|Idaho - South||2|
|Illinois - North||2|
|Illinois - South||3|
|Kansas - North||2|
|Kansas - South||3|
|Kentucky - North||2|
|Kentucky - South||3|
|Louisiana - North||4|
|Louisiana - South||5|
|Missouri - North||2|
|Missouri - South||3|
|Nebraska - NE and South||2|
|Nebraska - Northwest||1|
|Nevada - North||2|
|Nevada - South (except southern tip)||3|
|Nevada - southern tip||4|
|New Mexico - N||2|
|New Mexico - South||3|
|New York - North||1|
|New York - South||2|
|Oregon - East||2|
|Oregon - West||1|
|Pennsylvania - 2||2|
|South Dakota - Southeast||2|
|South Dakota - Southwest and North||1|
|Texas - North||3|
|Texas - Central||4|
|Texas - South||5|
Once you have located you Zone Climate number, go to the table below. In this table you are given the annual cost per square foot for heating and cooling your home.
Please note that these numbers are heat pump efficiency RULES OF THUMB. There are many, many factors that go into how much it costs to heat and cool a home:
However, below are average costs for an average home that could give you a little guidance as to what you can expect.
|Annual $ per Square Foot for Residential Heating and Cooling|
|Climate Zone||6 SEER/6 HSPF||8 SEER / 7 HSPF||10 SEER / 7 HSPF||13 SEER / 8 HSPF||14 SEER / 8 HSPF||16 SEER / 9 HSPF||18 SEER / 10 HSPF||20 SEER / 10 HSPF|
Let's take an example:
Imagine that you live in Tennessee and would like to know how much money it would cost to heat and cool your 2000 sq. ft home for the year. You are thinking about buying a heat pump but don't know what heat pump efficiency level you should purchase.
Going to the first table, Tennessee is in Zone Climate number 3.
Going to the second table, you retrieve the following $/sq. ft factors for Zone Climate 3:
These are the approximate amount that one with a 2000 sq. ft home could spend in Tennessee per year on their heating and cooling costs. The actual cost depends on the house construction and climate control habits of the occupants.
Compare this to your existing cost for heating and cooling in your home. If you currently have an old heat pump, for example 6 SEER/6 HSPF, compare the annual cost of using the above tables with your actual cost.
This will help you to see if your new heat pump efficiency calculation is higher or lower than what is realistic for your home.
Below is a table showing the SEER and HSPF of a number of residential and small commercial heat pumps on the market today.
Energy star is a U.S. government program which encourages manufacturers to market their equipment with a high energy efficiency.
The following are heat pump efficiency requirements for an Energy Star rating:
The Tier 1 energy star compliance applies only toward equipment manufactured between April 1, 2006 and January 1, 2009. In order for equipment to be energy star compliant after January 1, 2009, the heat pump or air conditioner must comply with the Tier 2 values.
Visit the U.S. Department of Energy for more heat pump efficiency information (as well as other heating and cooling energy data). It includes information on energy tax credits and building energy requirements.
Also for more information on energy star equipment visit www.energystar.gov.