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What Do All of These Energy Ratings Mean?

Sorting Out All of Those Numbers

Anyone, whether a home or business owner, has likely seen data related to energy rating listed on a product when shopping for a new cooling/heating system, or even a window unit. What do those numbers mean, and how do you compare one product to another? Understanding these numbers can save you a bundle on energy costs. We’ve provided some information below to help you make a smart, energy-wise choice.

Energy ratings

Energy ratings help you compare cooling and heating equipment to determine how much energy is necessary to keep you comfortable. Essentially, it is comparable to the miles-per-gallon you get in a car. Vehicles that use more gas require more money to get from one place to another. Efficiency numbers make it possible for you to know how much energy is consumed to enjoy the same performance you would get with similar products. When it comes to electric heat pumps or gas furnaces, you cannot compare ratings because these systems rely on different types of fuel. Whether your air conditioning and the heating system relies on electricity, gas, or both, understanding the numbers behind the ratings will give you a good idea of how much it will cost to run your system and enjoy a comfortable home or business.

Electric cooling and SEER (Seasonal Energy Efficient Ratio)

A SEER rating gives you a good idea of what you can expect to spend on energy costs, as this rating system measures the performance of the equipment over an entire season, such as summer months when most people need cooling.

How do you calculate SEER? It’s easy. Take the total cooling output the equipment will generate over the summer (BTUs, the measurement standard also known as British Thermal Units) and divide this number by your total energy expenditure (dollars spent) during this same period. You measure the cost to enjoy a cool home in comparison to the level of cooling power the system provides. Currently, the Lennox R XC25 is the most efficient cooling system available, providing a SEER rating of as much as 26. A minimum SEER of between 13 and 14 is mandated under federal law depending on the country where you reside. Air conditioners with a SEER of more than 14.5 may qualify for ENERGY STAR; when you see this qualification, you know it is a smart investment regarding energy-efficient cooling.

AFUE, or Annual Fuel Utilization Efficiency

AFUE numbers deal with systems that use fuels such as oil or natural gas to generate heat during colder months. This is a different method used to measure efficiency and is a comparison of the heat generated over the course of winter months with the amount of fuel burned.

Annual Fuel Utilization Efficiency numbers are fairly easy to understand. The higher the number, the more heat you will feel for a specific amount of oil or natural gas burned to produce that heat. Furnaces labeled 90% or higher for AFUE are highly efficient, as this means that 90% of the fuel is transformed into useable heat, and only 10% wasted. To go a step further in helping you understand AFUE rating, a furnace rated 80 will use 80% of the oil or natural gas to heat your home/business, wasting 20% of the fuel. The waste is typically caused due to inefficient burners, air leaks, or designs that are not as advanced as others. The Lennox SLP98V furnace currently has an AFUE of 98.7, which means less than 2% of the fuel is wasted – super efficient for winter months!

According to a January 2013 publication by the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) the XC25 air conditioner and XP25 heat pump are the most precise and efficient models available today, based on the SEER of similar heating and cooling products. For exact system efficiencies, you can consult with AHRI or a Lennox dealer such as Haley Mechanical.

HSPF, or Heating Season Performance Factor

Heat pumps don’t use fossil fuel and work as an air conditioner that’s capable of running in reverse to heat your home or business in winter months. Therefore, they have their comparative efficiency rating as AFUE does not apply in this case. How efficiently a heat pump warms your indoor air over the course of the entire winter is measured by HSPF. A heat pump with an HSPF of more than eight is considered high-efficiency; also, you may qualify for tax credits or utility rebates. How do you calculate HSPF? Divide the system’s heat output over the course of the season by the amount of electricity necessary to produce the heat.

Keep in mind that a heat pump will have an HSPF and SEER rating when shopping for this type of system because it relies on electricity to both cool and heat your premises. The Lennox XP25 heat pump mentioned earlier in this article currently offers an HSPF of as high as 10.20, and a SEER of up to 23.5.

Have questions about all these terms, numbers, and ratings? Give the SE Michigan heating & cooling professionals at Haley Mechanical a call today!

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