Your Letter Perfect Guide to Energy Efficiency
Admit it: You’ve seen those yellow EnergyGuide labels. They’ve been around for decades. Since 1992, the Department of Energy has set minimum energy efficiency standards, and rated the energy efficiency of most appliances, including air conditioners, heaters and furnaces.
But while you can hardly avoid those bright yellow stickers, understanding all those letters and numbers on them is not so easy. So here’s a quick guide to your EnergyGuide information.
SEER: Seasonal Energy Efficiency Ratio. Air conditioners are rated by SEER, a single number that is derived by dividing the unit’s typical cooling output (measured in BTUs) during the cooling season by the number of kilowatts needed to produce it. In other words, SEER measures how much energy is used to keep your house comfortable, and the higher the SEER number, the more efficient the unit is. Today, the minimum SEER required for new units is 13, but may go much higher. You can expect to save about 10% in energy costs for each digit the SEER goes up. That is, if you replace an old unit with a SEER of 10 with a unit with a SEER of 13, then you can expect up to 30% savings in energy costs.
HSPF: Heating Seasonal Performance Factor. HSPF is derived with the same formula as the SEER—that is typical heating output in BTUs divided by the kilowatts needed to produce it. The minimum HSPF is now 7.7.
While the SEER may be the better recognized rating, if you’re purchasing a new heat pump you’ll want to consider both those numbers to get the balance you need.
AFUE: Annual Fuel Utilization Efficiency. This rating doesn’t measure how much energy is needed to produce heat but rather how much of that heat escapes through the furnace flue, and thus the AFUE is expressed as a percentage. An 80% AFUE means 80% of the heat your furnace generates is delivered to your home, while 20% escapes through the flue. Beginning in September 2015, the minimum AFUE will range, depending on furnace type, between 80 and 83%.
Of course, there are factors besides these numbers that affect energy efficiency. Properly sized and installed units make a difference. (Units that are too large will negatively affect humidity and lessen efficiency; improperly installed ductwork will allow heat and cooling loss.)
So when shopping for a new heating and/or cooling unit, check the labels and get the whole picture. It’s the letter perfect answer for serious (and SEERious) savings!