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Keep comfortable, and stay in control of energy costs.

When efficiency is your priority, it pays to know the numbers.

If you're in the market for a new heating and air-conditioning system, you're probably concerned about energy efficiency. After all, heating and cooling account for almost half of a home's annual energy use.* So the more money you spend up front for energy efficient equipment, the more money you'll save every month on your utility bills.

But how do you know what is and isn't considered energy efficient?  When you understand the terms, it's easier to understand, and easier to compare different equipment to make sure you're getting the most efficient bang for your buck.

Cooling Equipment

When comparing air conditioners or heat pumps (in air-conditioning mode), the most popular energy rating is the equipment's SEER, or Seasonal Energy Efficiency Ratio.  SEER is similar to Miles Per Gallon in an automobile, in that it's a measure of how much you get out of the air conditioner, versus how much you have to put into it.

SEER is a measure of an air conditioner's total cooling output over a typical cooling season, measured in British thermal units, compared to the amount of energy required to get that amount of cooling, measured in watt-hours.  Another way to think of SEER is, it is a measure of how much cool air an air conditioner can create over the course of a summer, versus the amount of electricity it will take to do so.

SEER regulations

Regional map of the United States

The government mandates a minimum SEER rating for all equipment manufactured after January 2015, a rating that varies based on the part of the country in which you live.

The Northern region minimum is 13 SEER for air conditioners and 14 SEER for heat pumps.

The Southern region minimum is 14 SEER for air conditioners and heat pumps.

The Southwest region minimum is 14 SEER for air conditioners and heat pumps.

High SEER means high efficiency

If you want an air conditioner or heat pump that cools with high efficiency, look for a SEER rating of 16 or higher. An air conditioner of at least 16 SEER will produce substantial savings during the summer compared to older equipment. For example, the Lennox® XC16 air conditioner can save hundreds of dollars a year in energy costs compared to air conditioners that are just a few years old.

For the highest-SEER air conditioner on the market, check out the Lennox XC25 variable-capacity air conditioner, the most precise and efficient air conditioner you can buy (in 2016).**

Because it can adjust its compressor up and down in tiny increments, like a dimmer switch, the XC25 can use just the right amount of electricity to maintain a set temperature. So it provides plenty of cooling with very little wasted energy.

Heating Equipment

When it comes to warming your home, the two most popular methods are electricity and gas. Electric heat usually comes in the form of a heat pump, which is basically an air conditioner that can operate in reverse to move heat into your home, instead of out of it. Gas heat usually takes the form of a furnace, which uses a flame to heat a heat exchanger, a hot metal chamber that warms air as it passes through, and then circulate the warmed air throughout your home.

Heat Pumps

Electric heat from a heat pump is measured using HSPF, or Heating Season Performance Factor.  HSPF is similar to SEER, but instead of comparing cooling to electricity use, it compares heating to electricity use.

In other words, HSPF is a measure of the amount of heat a heat pump will create over a typical fall and winter, compared to the amount of electricity it takes to get that heat.  Like SEER, it is similar to MPG in an automobile.

An HSPF of 8 or higher is considered high efficiency, and will produce substantial savings compared to older equipment. Right now, the most energy conscious heat pump on the market is the Lennox XP25, the most precise and efficient heat pump you can buy.**


Gas furnace efficiency ratings are determined in a different manner than air conditioners and heat pumps. Gas furnace efficiency is measured in AFUE, or Annual Fuel Utilization Efficiency. AFUE is a measure of how much usable heat is generated when natural gas is burned in the furnace.  The higher the AFUE, the more heat you'll get from your natural gas, and the less gas you'll have to use to stay warm.

For example, an AFUE of 90 means that the furnace converts 90% of the fuel it burns into useable heat. An AFUE of 90 is also considered the minimum for a furnace to be considered high efficiency.

The most energy efficient furnace on the market right now is the Lennox SLP98V, the quietest and most efficient furnace you can buy (in 2016).***

Oil Furnaces

Many homes in northern climates use heating oil as a source of warmth instead of natural gas. Fortunately, the efficiency standard for oil furnaces is AFUE, the same as it is for gas furnaces.

See The Savings

If you'd like to see how much high-efficiency Lennox heating and cooling equipment can save you, please visit the Lennox Energy Savings Calculator. You can also schedule a visit from your local Lennox Dealer, who can help you find the most energy-efficient solution for your home. And remember, every dollar you spend toward efficiency means less you'll have to spend during summer and winter's worst weather.

*SOURCE: Energy.gov

** Efficiency claim based on comparison of air conditioning and heat pump products' SEER as published in AHRI (January 2015). Actual system combination efficiency may vary; consult AHRI for exact system efficiencies. Precision claim based on the cooling capacity range of the XC/XP25-036 units as compared to equivalent-sized competitive variable-capacity compressor units.

*** Based on sound pressure levels during steady-state, high-fire and low-fire operation of Lennox SLP98UH070XV36B and leading competitive units as of July 2013 at mid-point temperature rise and minimum external static pressure when set up per Section 4.4.4 of AHRI 260-2012. Based on AFUE efficiency rating of Lennox SLP98UH090XV60C and leading competitive units listed in AHRI directory as of March 2015. Efficiency ratings established per test standard ANSI/ASHRAE 103-1993.

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