What is SEER & EER?

Introduction

The Department of Energy (DOE) is directed by the Energy Policy and Conservation Act to establishing minimum efficiency standards for various consumer products; including central air conditioners and central air conditioning heat pumps. SEER and EER is a rating system created to measure the efficiency of an air conditioner or heat pump.

Both ratings should be considered in choosing cooling products. The rating is a ratio of the cooling output divided by the power consumption and measures the cooling performance of the system. The Federal government developed an ENERGY STAR program for high efficiency central air conditioning systems that in order to qualify must have a SEER of at least 14.

SEER rating

SEER stands for Seasonal Energy Efficiency Rating and is basically a number describing where an air conditioning unit falls on the efficiency scale, in regards to power consumption. It is calculated using the ratio of output cooling (Btu/hr) to input electrical power (watts).

Unlike EER, which is evaluated using a specific operating condition, SEER represents the overall expected performance of a unit, in a given location, for a typical year’s weather. It is measured using the same indoor temperature, but with an outdoor temperature range from 65 to 104 degrees fahrenheit.

The easiest way to think of a SEER number is by comparing it to how many miles per gallon a specific car is capable of handling. You might consider buying a Prius instead of a Hummer if gas prices is an issue. The same goes for a/c units – you would buy a unit with a higher SEER rating if you want a lower energy bill.

Concerning residential air conditioners, as of January 23rd 2006, new units sold in the United States by law must have a SEER rating equal to or greater than 13. Before 2006 the minimum standard was 10 (NOTE: A unit with a SEER rating of 13 is 30% more efficient than a unit with a SEER rating of only 10).

Homeowners are not required to upgrade to a higher efficiency model, but with an average lifespan of about 15 to 20 years low efficiency units (at least the ones below SEER 13) will eventually go away completely.

EER

EER is the abbreviation for Energy Efficiency Ratio and unlike SEER it does not take into consideration the time of year, but rather the system’s energy efficiency at a specific operating point. Just as SEER it is the ratio of output cooling (Btu/hr) to input electrical power (watts).

Recommendations by Laponica Refrigeration

While a consumers wallet is the number one deciding factor in purchasing a new unit there are some things a consumer should know about higher SEER ratings and the benefits of purchasing them.

If money is hard to come by Laponica Refrigeration recommends you at least try to purchase a SEER 16 unit. The savings you gain at that level will help pay for the extra cost in a minimal amount of time.

A unit with a SEER rating of higher than 16 may not necessarily provide the savings necessary to account for the extra cost, but they do tend to provide extra comfort accessories such as a variable fan speed on your indoor unit.

A variable fan speed keeps a more stable temperature in your house. In a standard air conditioner unit your indoor temperature will vary by approximately 3 degrees between cut-in and cut-out of the unit. Let’s say it is hot outside and you set your thermostat to 75 degrees. Your unit will cut off once it reaches 75 degrees. A normal unit will not turn back on before it reaches 78 degrees. This keep your house +/- 3 degrees from what you set it at. With a variable fan speed this does not happen and you end up with a more stable temperature inside your house.

 

References: 

United States of America. Department of Energy.ENERGY-EFFICIENT AIR CONDITIONERS: NEW STANDARDS COMING IN 2006 . Web. <http://www1.eere.energy.gov/buildings/appliance_standards/residential/pdfs/ac_factsheet.pdf>.

. “Seasonal energy efficiency ratio.” Wikipedia The Free Encyclopedia. Wikipedia, 13 2012. Web. 26 Nov 2012. <http://en.wikipedia.org/wiki/Seasonal_energy_efficiency_ratio>.

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What is HVAC and what does it mean?

Short Answer:
HVAC stands for Heating Ventilation, and Air Conditioning; it represents the technology used in climate control of indoor environments, whether it be in a residential/office building, automobile, warehouse, etc. Based upon the principles of thermodynamics, fluid mechanics, and heat transfer HVAC falls under the sub-discipline of mechanical engineering.

Longer Answer:
The meaning behind HVAC isn’t as difficult as it may sound. The definition is in the acronyms: It’s a system designed to heat, ventilate and condition the air in an enclosed environment. Contrary to popular belief “air conditioning” does not refer to cooling, but rather more general as in changing / alternating the temperature either up or down. It is as if you are conditioning the air to fit your requirements (whether it be up or down is irrelevant). It’s a more modern idea that air conditioning (A/C) entails chilling the air.

The General Idea:

The photo above actually describes the a/c unit in a car, but for educational purposes it’s a little less clustered and explains the general idea.

Any air conditioning unit circulates air using pressure and a few rules of thermodynamics within an enclosed system. The cool air felt from an a/c doesn’t actually come from the freon itself, but rather from the effects of heat transfer. When heat moves it causes a low pressure behind it which feels cool. Ever noticed how one can sometimes feel a gust of cold air blow on you when opening a refrigerator  It’s not cold air from refrigerator  but rather a combination of warm air in the room and a persons own body heat rushing into the fridge. An environment will always want to be in equilibrium, which is why you feel that gust of air even though what you are actually feeling is heating moving away from you.

The following four steps explain the general idea:

  1. The compressor increases the pressure of freon turning it from a gas into a liquid and pushes it towards the evaporator.
  2. Moving towards the evaporator excess heat is ventilated by passing through a condenser and fan.
  3. Once the liquid reaches the evaporator pressure is quickly lowered causing the freon to turn into gas. Thermodynamics demands that heat in an environment to always be in equilibrium. When a liquid turns into gas it undergoes a process called phase conversion. During this process the liquid/gas absorbs heat from it’s surrounding environment making the surrounding air cooler. A fan by the evaporator blows this cold air into the room.
  4. From the evaporator coil the freon is pushed towards the compressor where it once again turned into a liquid and the process starts over.

Some Fun History Stuff:
The process of cooling the air has been around since the early civilizations. The most notable empires to have used some type of temperature regulation are the Roman and the Persian civilizations.

Rome: Only available to the extremely wealthy, the Romans circulated water from their system of aqueducts through pipes in the wall. The circulated water cooled the buildings walls and by that manner cooled the entire home.

Persia:

The Persians used wind ventilation design called a windcatcher or Malqaf in Arabic. A building would be designed with 1 to 8 openings to catch air flow from one or more directions and releasing it causing a draft. This system does not rely on any type of cooling device, but rather relies more on ventilation and air flow to cool the building. (Javaheri)

 

Article References:
“Wikipedia.” HVAC. N.p., 10 2012. Web. 16 Oct 2012. <http://en.wikipedia.org/wiki/HVAC>.

Glass, Nick. “CNN.” Ancient ‘air-conditiong’ cools building sustainably. CNN, 08 2012. Web. 16 Oct 2012. <http://www.cnn.com/2012/02/28/world/asia/ancient-air-conditioning-architecture/index.html>.

Howard, Sawyer. “Coolers Used by Ancient Romans.”eHow – Discover the expert in you.. eHow, n. d. Web. Web. 16 Oct. 2012. <http://www.ehow.com/info_8370402_coolers-used-ancient-romans.html>.

Javaheri, Elyana. “How Ancient Persian Architecture Captured Wind Energy Underground to Green Buildings.” thisbigcity. thisbigcity.net, 20 2012. Web. 16 Oct 2012. <http://thisbigcity.net/how-ancient-persian-architecture-captured-wind-energy-underground-to-green-buildings/>.

Media References:
Image 1: A-C. N.d. Mt. Healthy Auto RepairWeb. 16 Oct 2012. <http://www.mthealthyautorepair.com/A-C.html>.

Image 2: Fellanamedlime, . Malqaf.jpg. 2010. WikipediaWeb. 16 Oct 2012. <http://en.wikipedia.org/wiki/File:Malqaf.jpg>.